# DSWM13 Switch



## west99999 (May 12, 2007)

Anybody got any info on the new SWM13 switch that is coming out soon?


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## gov (Jan 11, 2013)

Halloween reference of some kind ??

:eek2:


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## west99999 (May 12, 2007)

No it is a real SWM switch. I just don't have much info on it and wanted to see if anyone else did.


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## peds48 (Jan 11, 2008)

It is for DRE and D2

Click for large view - Uploaded with Skitch


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## gov (Jan 11, 2013)

Interesting.

Funny to see a '13' thing on Halloween, in an electronic device no less. Engineers being big on 2, 4, 8, 16 etc., LOL.


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## HoTat2 (Nov 16, 2005)

Wonder how they did it to make room for 5 more SWiM carriers?

Reduced the SWiM carrier spacing below the current ~102 MHz?

Went to higher carrier frequencies than 1790 MHz?

Some of both? 

Yes, interesting ...


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## slice1900 (Feb 14, 2013)

It is interesting they're calling it a "Digital SWM". That implies it is somehow different from a regular SWM, beyond having 13 channels. Currently a legacy LNB frequency shifts satellite signals from 10-20 GHz range to lower frequencies that regular coaxial cable can carry, and stacks them onto 4 cables to make them easier to deal with. The SWM is sort of a second stage LNB, in that it does more frequency shifting and stacks individual transponders onto a single cable, making it even easier to deal with. But it still working only with analog RF, which needs to be decoded by a tuner for the original digital data to be recovered.

I've posted a few times that I thought Directv would eventually take the tuners out of the receivers and put them in the SWM. If you tune them in the SWM and deliver decoded digital data - which wouldn't even need to travel via coax - then everything is a client of the SWM. Even DVRs.

Maybe that's what they've done here, and you have 13 (14, if you include the guide channel) tuners in the SWM and there are no SWM channels, as such, but instead 13 DECA channels that are accessed by attached receivers and DVRs via RVU. Hotels would love that, if they had RVU capable TVs they wouldn't even _need_ receivers!

That's my hunch at least, we'll see if I'm right or wildly off the mark


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## slice1900 (Feb 14, 2013)

The "why 13" would be that they probably have implemented 16 tuners on a single chip (or maybe 8 on two chips, I don't know how big they are) Tuning is a parallel task, which would be implemented with sort of a semi-custom DSP (digital signal processor) Such highly parallel functions are often designed with 'spares' to account for defects in the chip fabrication process.

Those who are familiar with the specs of higher end GPUs will be familar with this, the not quite high end models from ATI and Nvidia are the same chip as the high end models with a few defective areas (cores, clusters, whatever marketing chooses to call them) disabled, because otherwise they'd be tossing out a lot of almost good chips to get a small number of fully functional ones, and high end GPUs would cost 10x as much as they do.

So if you need 14 (13 + guide channel) tuners to work, you design for 16. Two can be bad in manufacturing, or go bad later, and get disabled and you still have fully functional hardware.

13 would seem to be a very good number for a later SWM LNB residential version of this, to avoid needing SWM16 upgrades and running a bunch of extra coax when customers add a Genie to their account.


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## slice1900 (Feb 14, 2013)

One more thought, this might be what Directv was talking about in late May when they made that comment about coming up with better solutions for customers receiving OTA broadcasts. Tuning satellite and tuning OTA ATSC broadcasts isn't the same, but they have enough in common that adding ATSC demodulation capability to a satellite demodulator isn't going to double the complexity, or even increase it by 50%. Perhaps much less than that.

The really low down hard RF stuff would be on a separate chip from the DSP anyway, because analog RF and high speed digital logic don't 'play well' together. Likely there would be separate chips for satellite and ATSC for that part of the process, since I don't think they'd share much there (but I could be wrong, I know the digital side but not the analog side) They'd share the DSP on the back end, it would merely run a different program to deal with the rest of the job for ATSC demodulation versus satellite demodulation. It just depends how much of the process is the kind of ugly analog stuff that a DSP wouldn't want to share silicon with.

I'm pretty sure that ATSC licensing is done per product, not per tuner, so it wouldn't cost Directv all that much more to make the DSWM13 capable of tuning 13 ATSC channels at once versus just one or two. 13 is probably overkill, but they could do enough that hardly anyone would ever run into issues with lacking ATSC tuning capacity. One model of the DSWM13 could include the ATSC analog side chip(s) and have an OTA in port to allow it to tune ATSC channels. You'd receive those via DECA/RVU just as you can today using a Genie client where the Genie has an AM21. Hopefully it'll be capable of scanning for channels 

The one hitch to a DSWM LNB with OTA capability would be people with indoor antennas - how to get the signal back to the DSWM's tuner? The only way I can see would be if the DECA channels the DSWM used were higher in frequency than the current range, to allow carrying the 50-700 MHz ATSC from the user's antenna to the DSWM.


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## Drucifer (Feb 12, 2009)

Hopefully it is cooler.


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## slice1900 (Feb 14, 2013)

I googled for "digital SWM" and found a couple patents regarding it (as well as some guy's resume, but the link is dead)

US8509722 Frequency drift estimation for low cost outdoor unit frequency conversions and system diagnostics
US8238813 Computationally efficient design for broadcast satellite single wire and/or direct demod interface

Here's the overview from each:



> Overview
> 
> Recent advances in high speed Analog to Digital (A/D) converters open up the possibility of direct A/D conversion of baseband or near baseband 500 MHz wide Satellite downlink signals. This allows for all-digital demultiplexing (demuxing) of one or more 500 MHz complexes or transponders and subsequent all-digital multiplexing (muxing) of a selected subset of these transponder channels onto a single wire interface for home distribution. With such a digital implementation, selected transponder baseband I/Q signals may be selected for direct demodulation, for subsequent home or multi-dwelling distribution over any suitable physical/network layer protocols.
> 
> ...


I only did a quick scan of these patents, there's a lot of technical stuff in there that's way beyond my meager RF knowledge. Interesting that it is dealing with entire 500 MHz blocks at a time! I suppose in the far future this would allow Directv to use their 500 MHz frequency bands as a single block, without any spacing between transponders as currently implemented. I think I read somewhere that Directv is using 250 MHz wide transponders for some uplinks, so the technology is there. Taking advantage of that currently wasted guard band space between transponders would be many years away however, as everything would have to be replaced by Digital SWM for that to happen. However, maybe this would be done for new bands that might need new equipment anyway, such as the RDBS bands on D14 and D15.

It sounds like what I was describing, but this says they're doing it entirely digitally! I wouldn't have thought that could be close to cost effective, but maybe that's why it is targeted at DRE first, these things may make a SWM32 look like a bargain by comparison.

I'm sure someone who knows way more about RF than I do, such as VOS, would get a lot more out of an in-depth reading of these patents than I would. It does include an interesting overview of how SWM currently works, as well as how digital SWM is done differently.

I also found an asset purchase agreement where Entropic Communications (who invented the technology behind SWM) purchased Digital SWM ASIC IP from PLX last year.

http://www.sec.gov/Archives/edgar/data/850579/000085057912000087/plx_exhibit2-1.htm


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## inkahauts (Nov 13, 2006)

I think they tightened up the channels and fit more in. I don't think its anything beyond that by I guess time will tell. And I suspect if it goes
Well we could see them in lnbs at some point.


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## slice1900 (Feb 14, 2013)

Unless those patents aren't what the DSWM13 is, they did WAY more than tightening up the channels.


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## harsh (Jun 15, 2003)

Looking at the DRE certification training ad slick from a couple of years ago, it recommends coursework/experience in Linux.

Thinking back, it seems like the theoretical practical limit of SWM was 11 channels.


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## JosephB (Nov 14, 2005)

What are the implications for existing equipment in the field? 

If it's simply tightening up the current SWM channels or cramming more in there, what's the possibility that existing tuners can be modified by software (either changing their baseband or the software higher up the stack in the receiver) to be compatible? 

If it is a wholesale re-do of SWM, including moving to digital processing of the signals, I wonder how flexible the current tuners are to use this as well?


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## longrider (Apr 21, 2007)

I do not see existing equipment in the field being an issue. It was sated earlier that it was for DRE and D2 Advantage which are hotel and MFH technologies. Just like the old HR20i for MFH3, coming up with a new receiver for those markets would not be an issue.


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## JosephB (Nov 14, 2005)

longrider said:


> I do not see existing equipment in the field being an issue. It was sated earlier that it was for DRE and D2 Advantage which are hotel and MFH technologies. Just like the old HR20i for MFH3, coming up with a new receiver for those markets would not be an issue.


Ok, I got it, I didn't pick up that those are MDU only. That brings up another question, though, I thought one reason/advantage for doing SWM in MDUs is that you can use the same equipment? Does this mean MDU users will slide back into the problems where a really old receiver is their only option?


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## slice1900 (Feb 14, 2013)

The output of the DSWM is pure digital MPEG data, same as what a Genie's tuner decodes from the transponder embedded within the SWM channel which it sends to a client via DECA. So in theory any DECA capable receiver should work. There's no requirement for coax, in fact in hotels I suspect it is probably going to use TCP/IP over cat5 more often than coax and use wired C41 clients (or RVU capable TVs)

Based on a DECA "mesh test" maxing out at 250 Mb/sec and a full HD channel bandwidth of around 19 Mb, that divides out to 13 channels fitting within the current DECA point to point bandwidth capability (plus whatever is left over for the guide data stream) Maybe that's just a coincidence, since DECA as currently defined has only 3 50 MHz wide channels, but... More likely it increases the frequency range for DECA. 10 or 11 more 50 MHz DECA channels requires 500 or 550 MHz, and there's plenty of room in the sub 900 MHz range DECA inhabits. The implementation chosen between those two depends on the flexibility of the receiver's DECA hardware.

The patents indicate they have been working on this Digital SWM technology for some time, and likely waiting for the technology to mature to the point where the cost was reasonable. I'd say at the very worst it would be limited to the most recent SWM only equipment, or maybe they had enough forethought to build in capability long enough ago that all still supported receivers are included. Given that Directv knew they were going in this direction for a while, they'd be able make whatever accommodation to their hardware and software implementation of DECA to provide for DSWM and make as much of their current installed base DSWM ready as possible.

BTW, I found a few references in Linkedin to Digital SWM, which indicates that the ASIC was implemented in 45nm CMOS. That's one (and soon to be two) generations behind the state of the art, so there's ample room to drive improvements in cost/performance when they migrate this from DRE to residential since it is a fully digital design with no analog component implemented in Gallium arsenide to hold it back. The DSWM will be able to follow Moore's Law on down to higher performance and/or cooler and/or cheaper hardware every two years like other CE products. Just look at how much faster this year's iPhone is than the original six years ago.


The beautiful thing about this for hotels is that there is no reason that the DSWM's ASIC can't be programmed to do more than decode Directv. Decoding ATSC, QAM or even NTSC should be possible with the same hardware, so it'll be nice for adding in local OTA channels or modulated internal channels. Given that it handles a 500 MHz block at once, this thing should be capable of tuning the entire ATSC spectrum simultaneously...that's pretty cool! Since there's no additional hardware needed, it won't cost anything to provide this functionality, aside from the patent licenses needed for ATSC and QAM, and of course the developer effort. That's not likely to be a high priority for Directv, but I'll bet it is on someone's 'to do' or 'nice to have' list.


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## slice1900 (Feb 14, 2013)

I found more info on this, which would tend to make me think it isn't necessarily using DECA - at least it would also have the option to use ordinary SWM. The ASIC was described in an ISSCC paper earlier this year, and the intro (which is all I saw, the rest is behind a paywall) states the ASWM [i.e. the SWM8/16/LNB of today] will "select and output signals from multiple LNB's to a fixed frequency slot for each set-top box on a single cable". That's the "frequency shift a transponder into a SWM channel" model we have now. In the DSWM "selected and reordered channels are digitally upconverted and are stacked into L-band through a 9b 5.46GS/s DAC" and "offers a full flexibility of channel selection, and supports many more satellites through a single L-band cable".

So as I previously outlined, the DSWM is digitizing the individual channels it wants, but this indicates it is then capable of digitally frequency shifting and converting them back to analog. ["DAC" means "digital to analog converter"] I had almost suggested this as a possibility in my last post, but I'm already writing such long posts I'm probably causing most people's eyes to glaze over already  Analog L band - that would mean the DSWM could be utilized by any SWM capable receiver, even the venerable H20.

However, unlike current SWM, since it is working at the level of individual Directv channels, it could theoretically fit at least 40 _unique_ HD channels in SWM this way (based on 5 HD channels per transponder) Maybe well over 100, depending on how receivers handle the SWM guard band. It would do this by placing channels intended for multiple receivers into shared SWM channels. Just like SWM does now, when two receivers happen to tune channels available from the same transponder, but it could cause as many receivers to share a single SWM channel as there is room for the channels they want. Not sure where the apparent limit of 13 in the current DSWM-13 would come from, unless it is simply limited by power/heat budget at this time. If so, that will improve with time.

One other thing stood out with these two quotes, first about DSWM: "supports many more satellites through a single L-band cable" and the second regarding the limitations of ASWM: "Although the ASWM solution solves the problem of multiple cables, it does not provide enough flexibility and capability to increase the number of inputs". That makes me wonder if they're planning ahead for adding even more capacity. Perhaps soon enough supporting RDBS on D14 and D15 would require two more coaxial cables, as has been discussed as a possibility in the D14 speculation thread. If you can support 40 unique channels in a DSWM (or even half that many) you don't have to worry about annoying residential (or small commercial) customers with six cables. Only larger MDUs would have to deal with that, everyone else would have a DSWM LNB and a single coax.


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## inkahauts (Nov 13, 2006)

I didnt see any way they'd ever mess with the deca freq with the swim channels because then that'd screw up their Whole Home Service. 

Well I have to wonder. Are they looking at the future? Maybe they will try as move deca to a offerer freq range up a bit higher and let over the air be diplexed in again? Also expand deca range to cover moca2 specs? So more nodes possible? Could that be the reason they are limiting it to 13 channels. Or maybe the equipment can't deal with more than 13 channels of swim. Don't know. 

That would be perfect if they could run 40 channels of swim though which would equate to 40 channels on a lnbswim. Would Make everything easier for everyone. But even 20 channels would be plenty for most consumers.


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## veryoldschool (Dec 10, 2006)

My few cents:

The current SWiM doesn't share when two receivers are tuned to the same transponder.
The external SWiMs also have six inputs, so there is "some room" for more SATs.

MoCA 2.0 wouldn't be a major change should DirecTV want to change. It uses 100 MHz BW and the splitters already are spec'd for 475-625 MHz.
It is backward compatible too and ups the node limit to 32.

As for the DSWM, if the current thoughts hold true, it's an evolution of the current SWiM, "but" will have more of a receiver so it can decode "a channel" from the transponder. This will then be encoded [modulated] onto an RF signal and become "a SWiM channel".
Software in the receiver should be able to "fine tune" to these new frequencies, but "I doubt" we'll see 40 channels, if they're starting at 13, since this requires 13 tuners and encoders/modulators.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> My few cents:
> 
> *... As for the DSWM, if the current thoughts hold true, it's an evolution of the current SWiM, "but" will have more of a receiver so it can decode "a channel" from the transponder. This will then be encoded [modulated] onto an RF signal and become "a SWiM channel".*
> *Software in the receiver should be able to "fine tune" to these new frequencies, but "I doubt" we'll see 40 channels, if they're starting at 13, since this requires 13 tuners and encoders/modulators.*


That's my thinking as well VOS;

While still racking my brain trying to fully understand exactly "how" it's done with things like "DSWM Channelizers," or "Coarse-fine" Granularity Channelizers" suggested in the patents posted by slice1900.

It appears what the DSWM does is take SWiM technology to the next evolutionary level from de-multiplexing and frequency translating an individual transponder from the triple 500 MHz block legacy stack to that of de-multiplexing and demodulating down to an individual channel carried on a transponder. This demodulated channel as an I/Q baseband signal in turn modulates one of the now 13 SWiM carriers for transmission over coax/splitters to the IRDs.

Since it is only a single channel within a transponder being sent to the IRDs instead of the entire transponder multiplex, this is obviously a much more narrow-band signal of course, allowing for a much closer spacing of the SWiM carriers than the present ~102 MHz, creating room for additional SWiM carrier channels (5 more in this case) likely within the same 974-1790 MHz (end carrier center frequencies) spectrum.


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> That's my thinking as well VOS;
> 
> Since it is only a single channel within a transponder being sent to the IRDs instead of the entire transponder multiplex, this is obviously a much more narrow-band signal of course, allowing for a much closer spacing of the SWiM carriers than the present ~102 MHz, creating room for additional SWiM carrier channels (5 more in this case) likely within the same 974-1790 MHz (end carrier center frequencies) spectrum.


I think why we won't be seeing 40 channels is due to the [legacy] receiver's bandwidth.


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## inkahauts (Nov 13, 2006)

I was thinking costs more than anything which is why id sooner expect that as only a commercial or hotel or mdu system like the swim32 and only have a swim13 for residential. 

To bad they didn't go to 15 if they could though. 

I bet costs dropping over time will help too.


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## veryoldschool (Dec 10, 2006)

inkahauts said:


> I was thinking costs more than anything which is why id sooner expect that as only a commercial or hotel or mdu system like the swim32 and only have a swim13 for residential.
> 
> To bad they didn't go to 15 if they could though.
> 
> I bet costs dropping over time will help too.


Who knows....

Remember there was a SWM5 before a SWM8.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> My few cents:
> 
> The current SWiM doesn't share when two receivers are tuned to the same transponder.
> The external SWiMs also have six inputs, so there is "some room" for more SATs.


I've been told current SWM shares channels by others on dbstalk, but I've never tested that, so I have no reason to doubt your statement. At any rate, there's nothing stopping the DSWM from assigning multiple receivers the same SWM channel, so long as the DSWM made the Directv channel each wants available on that SWM channel. If the SWM channel assignment to the receiver is fixed, then the DSWM would have to create its own SWM channels to do so. And it will (but not the DSWM13, see below)

I recently noticed Sonora had a new model of amplifier, which has 6 inputs/6 outputs like the model it is replacing, which I confess at the time made me wonder if Directv might have plans to use more inputs for RDBS, given that Sonora would undoubtedly be aware of Directv's future plans. Of course, Sonora might have left it there "just in case".



veryoldschool said:


> As for the DSWM, if the current thoughts hold true, it's an evolution of the current SWiM, "but" will have more of a receiver so it can decode "a channel" from the transponder. This will then be encoded [modulated] onto an RF signal and become "a SWiM channel".
> Software in the receiver should be able to "fine tune" to these new frequencies, but "I doubt" we'll see 40 channels, if they're starting at 13, since this requires 13 tuners and encoders/modulators.


Well, unfortunately I have to eat my words about what I said before. I finally had time to sit down and read both patents in detail, instead of giving them a more cursory examination (i.e. skipping ahead to the end figuring that's where the good parts are) There are no tuners or modulators (even digital equivalents) in the DSWM13. The patents actually describe three (or four, depending on how you count them) embodients of a Digital SWM, which is why I should have read them in their entirety before commenting 

The first is very likely what the DSWM13 is. While it is "digital" in terms of using ADCs to digitize the entire RF bandwidth being transmitted by Directv, it isn't performing any higher order digital operations. It fits 13(14) channels where 8(9) used to go, using an entire transponder at a time. Basically it uses smaller guard bands as has been previously suggested. This device is figure 4 & 5 from the patents. What I've seen elsewhere suggests it is also cheaper than current SWM due to the elimination of SAW filters.

Figures 4 & 6 is the second embodiment, which utilizes some higher order digital functions but still operates at the transponder level. Of note, it describes the choice of a 32 point FFT, _despite a maximum _[for SWM]_ of 26 channels_, because powers of two simplify the FFT implementation. So we might reasonably expect a DSWM26 in the future utilizing the technology in Figure 6.

Figures 4 & 7 is the third embodiment, which is what I've been describing, but we may not see for a while. It operates not on transponders but on individual channels, computing I/Q data for each channel of interest. These can either be pasted together on the fly and converted back into analog SWM channels (with at least 100 HD channels possible from the 26 SWM channels) or can be sent via IP.

The patent actually lists several possibilities for this third embodiment, adding further processing of the I/Q data, to the point where it is fully demodulated. So we may have to wait until the 4th generation DSWM to get one that can work directly with RVU devices as I was suggesting. Though depending on how long it takes to get there, there may well be a competing protocol which Directv would use in preference to RVU.


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## inkahauts (Nov 13, 2006)

Who knows....

Remember there was a SWM5 before a SWM8.


Ha! I still have my swim5!!!


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## inkahauts (Nov 13, 2006)

slice1900 said:


> I've been told current SWM shares channels by others on dbstalk, but I've never tested that, so I have no reason to doubt your statement. At any rate, there's nothing stopping the DSWM from assigning multiple receivers the same SWM channel, so long as the DSWM made the Directv channel each wants available on that SWM channel. If the SWM channel assignment to the receiver is fixed, then the DSWM would have to create its own SWM channels to do so. And it will (but not the DSWM13, see below)
> 
> I recently noticed Sonora had a new model of amplifier, which has 6 inputs/6 outputs like the model it is replacing, which I confess at the time made me wonder if Directv might have plans to use more inputs for RDBS, given that Sonora would undoubtedly be aware of Directv's future plans. Of course, Sonora might have left it there "just in case".
> 
> ...


Ah well this makes a lot more sense IMHO in terms if a road map for the future.

I can see an entirely new system when they go to a per channel swim system. As you say out all the tuners in the swim have a box anywhere that's your DVR an not even connect it to your tv and then small clients at all tvs.

And 100? Now we are talking easy time for commercial situations.

I wouldn't be surprised if they waited for implement of this type of tech before they began shutting down mpeg2 sd.

I do enjoy fun speculation without knowing what they are really planning and for when.


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## P Smith (Jul 25, 2002)

by cursory reading, there will not be demodulation/modulation of channels; IMHO it will come to shifting and making bandwidth close to transponder's bandwidtn;
demod process is still be done by receiver's chip


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## slice1900 (Feb 14, 2013)

inkahauts said:


> Ah well this makes a lot more sense IMHO in terms if a road map for the future. I can see an entirely new system when they go to a per channel swim system. As you say out all the tuners in the swim have a box anywhere that's your DVR an not even connect it to your tv and then small clients at all tvs. And 100? Now we are talking easy time for commercial situations. I wouldn't be surprised if they waited for implement of this type of tech before they began shutting down mpeg2 sd. I do enjoy fun speculation without knowing what they are really planning and for when.


Why do you think they'd wait to do this for when they began shutting down MPEG2/SD? How would that make this any easier to implement? I would think they'd want to implement it as soon as it was ready and the cost/power was where they feel it needs to be.

Given that they apparently still install SD dishes for new SD only customers even now, it will be many years before they can even think about shutting down MPEG2/SD. Since the DSWM is cheaper to build than ASWM (or will be once they make it in volume) maybe it'll change the cost enough that they start installing a DSWM LNB even for new SD only installs. That's really the first step for MPEG2 retirement.

The per channel third embodiment sending I/Q data would let them remove tuners from all the receivers, but as you say you'd still need some sort of device somewhere to store recordings, but more importantly to provide the UI to the clients/RVU TVs.

Whether they would ever implement the final step in the third embodiment and do the demodulation of I/Q data in the DSWM is an interesting question. So long as they need some sort of "server" it doesn't really matter if the demodulation happens in the DSWM or in this device. Theoretically the TV could also do it, it has the hardware to demodulate ATSC and QAM, it is just a matter of programming it to handle Directv's modulation scheme. The thing is, without a server the TV would have to also have the Directv UI programmed into it for this to be useful, and unless the capability to do stuff like that was added in a future version of RVU or a similar protocol, I don't see that happening (outside of maybe a few special models created for the hotel industry)


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## slice1900 (Feb 14, 2013)

BTW, not really related to the DSWM, but interesting nonetheless. When looking for other DSWM related patents I found various other patents Directv has filed. Most were not interesting to me, but may be to others - various features for DVRs and what not. One caught my eye. Check out patent 20130174192, "Method and system for detecting unauthorized use of a set top box using weather profiles". Yes, it is exactly what it sounds like.

http://www.google.com/patents/US20130174192

Quite clever, I must say, they'd catch everyone using receivers in a second home without paying if they ever implemented this! Not to mention everyone using Directv in Canada or Mexico using a US service address.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I recently noticed Sonora had a new model of amplifier, which has 6 inputs/6 outputs...
> 
> Well, unfortunately I have to eat my words about what I said before....
> .... While it is "digital" in terms of using ADCs to digitize the entire RF bandwidth being transmitted by Directv, it isn't performing any higher order digital operations.


The two flex ports have been around since the WB68. They were/are for the 95 & 72.5 SATs, but 72.5 isn't used anymore.

When speculating there will be paths that don't turn out [dead ends].
I think you're over reaching with "digitizing the entire RF bandwidth being transmitted by DirecTV".
We're dealing with a single wire [coax] and must stay in the frequency domain for more than one "signal".

I'm going to agree with P Smith that there is better filtering allowing the spacing of the SWiM channels to be closer.
He's posted screen shots of the current SWiM output and the spacing "can be improved" for more channels.


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## P Smith (Jul 25, 2002)

while it could be hard to send just I/Q signals of particular _transponder_ not a _channel_ (!) (last time it's a trend to shorten the physical path by combining a tuner with demod in one chip - see Broadcom latest chips), I would point out to an encryption of frames [see DTV patents about ACM] for AC3 aka MPEG-4 DTV transponders what would required to control demods for each tpn ... I would say not that easy as you could discuss here


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## veryoldschool (Dec 10, 2006)

I'm going to do a little "2+2" here.
I may get 3 or 5 :lol:

The current Entropic chip handles 3 channels.
Three chips and we have the 8 SWiM + guide.

A SWiM13 doesn't "add up" since with the guide it's 14.

"So":
Entropic's new chip handles 2 channels with digital filters.


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## HoTat2 (Nov 16, 2005)

OK;

So to summarize, look for the DSWM13 to likely use digital filtering and conversion to produce tighter spacing of the SWiM carrier channels to create more room for an additional 5 more?

Possibly to around 60-70 MHz spacing instead of 102 MHz?

That is, somewhere in the area of 9/14 x 102 MHz. 

But asides this, it will maintain the same traditional scheme of converting an entire transponder multiplex to a SWiM channel?


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## P Smith (Jul 25, 2002)

when we'll have I'll post spectrograms and will do the measures (if it will fall in my hands)


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> OK;
> 
> So to summarize, look for the DSWM13 to likely use digital filtering and conversion to produce tighter spacing of the SWiM carrier channels to create more room for an additional 5 more?
> 
> But asides this, it will maintain the same traditional scheme of converting an entire transponder multiplex to a SWiM channel?


That seems about right.
The hardest thing for a tech will be the change of tuner limits. :lol:

Right now DirecTV requires all eight channels for a Genie install with an MDU.
It "looks like" they'll allow two on this SWiM.


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## texasbrit (Aug 9, 2006)

veryoldschool said:


> My few cents:
> 
> The current SWiM doesn't share when two receivers are tuned to the same transponder.
> The external SWiMs also have six inputs, so there is "some room" for more SATs.


Unless it has changed along the way, the SWM does share when two receivers are on the same transponder. I checked this some time back, after the SWM8 was released.. If you set the receivers to the same transponder, you could add more than eight tuners to an SWM8 multiswitch. I think I tried 11 on one occasion. Then as you changed the receivers to different channels, you had no problem until you had eight different transponders selected. You could also see this in the way the SWM channels were used.
Maybe the SWM LNB is different, I don't know.


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## veryoldschool (Dec 10, 2006)

texasbrit said:


> Unless it has changed along the way, the SWM does share when two receivers are on the same transponder. I checked this some time back, after the SWM8 was released.. If you set the receivers to the same transponder, you could add more than eight tuners to an SWM8 multiswitch. I think I tried 11 on one occasion. Then as you changed the receivers to different channels, you had no problem until you had eight different transponders selected. You could also see this in the way the SWM channels were used.
> Maybe the SWM LNB is different, I don't know.


This doesn't match the old SWM screen.
Each tuner would get assigned a channel and it never "released" it.
You may have gotten more than eight tuners to "work" by having more than one on the same TV channel, but the SWiM itself doesn't share, or show any sign of giving up a channel when two tuners are on the same TV channel.

Error code *49* | Primary Tuner Connection Problem - No SWM channels are available. The receiver is unable to register tuners for Live TV or Recordings because there are too many receivers connected to the coax network


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## gov (Jan 11, 2013)

Mentioned the SWM13 to a local D* installer, and he said his first thought was 8+5 is 13, so maybe the 8 part is just a SWM8 pure and simple, and the extra 5 have to go to a Genie, which has a different, compatible way of handling it's 5 extra. He was speculating a SWM13 would not support 6 HR2Xs (12 tuners), but it might support 2 Genies (10 tuners) and an HR2X and an H2X (13 all together).

But he added, he had heard nothing from management, and was just guessing.

He also said management never tells them nuthin', but I suppose we already knew that.

:sure:


Sparky school for me was early 80s, so I be clueless how it works, and thankfully so. 

:righton:


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## veryoldschool (Dec 10, 2006)

gov said:


> Mentioned the SWM13 to a local D* installer, and he said...
> 
> But he added, he had heard nothing from management, and was just guessing.


I think this might be an "uneducated" guess. :lol:


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## JosephB (Nov 14, 2005)

Yeah, it seems if this is meant for hotels and whatnot, the 5 "bonus" tuners for the Genie wouldn't really make sense. In the end, how much more sense does this make than just using SWM-8 and SWM-16 modules? If you include the cost to develop this technology, along with the fact that there are DSPs and other more advanced technologies in this than a normal SWM, what do you get? I suppose you could modestly reduce the number of modules if you were loading racks with SWM-8s in a hotel or dorm or hospital type situation.

But, in an MDU it seems like this would be a bad choice. Generally one would think in a condo or apartment you're generally going to see fewer tuners per unit than single family homes, and with it being 13 tuners you now have an uneven balance if you were to split the single DSWM between two units. Plus, you have the need to isolate the MoCA networks between two units. 

I'm just confused why it was worth their time and money to build this when SWM8 and SWM16s are only in the range of $100, and that is the consumer cost at Solid Signal--DirecTV's cost has to be less than that.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> When speculating there will be paths that don't turn out [dead ends].
> I think you're over reaching with "digitizing the entire RF bandwidth being transmitted by DirecTV".
> We're dealing with a single wire [coax] and must stay in the frequency domain for more than one "signal".


I'm quite certain it does exactly that. I'm not sure I understand your comment about how we're dealing with single wire coax. The output of the DSWM is single wire, but the input is the same legacy input that current SWM has. It is the input it is digitizing, outputting 13 SWM channels spaced more closely than current SWM to use the same or very similar frequency range. The drawings on the patents and the description itself is very clear that it does the following:

We can assume the legacy portion of an LNB is unchanged, or at least any changes are not referenced in these patents. The only change mentioned in the patents is the possible addition of feedback from the DSWM to tweak the DRO (dielectric resonant oscillator, or what we call a LO) frequency to correct for LO frequency drift.

The input to the DSWM is 8 "LNBs". Figure 3b in the patent shows what these contain: 99 odd, 99 even, 101 odd, 101 even, 103 odd, 103 even, 119 odd, 110/119 even. That doesn't mean it would actually expect 8 cables, figure 3b represents a DSWM LNB, getting 8 traces from the legacy side to the DSWM side. When an external DSWM is connected to a legacy LNB it would still take four cables but do this splitting out internally. These 8 pathways are frequency shifted using DROs so the bottom is at near baseband (starting between 10 and 100 MHz) This is shown in the center of figure 3b in the patent - the circles with X's marked 328 are the DROs.

From there, the Ka pathways are split so hi and lo can be handled separately, increasing the count to 12 pathways, as shown on the left side of figure 4. All 12 pathways are passed through anti aliasing filters, high pass AA filters for Ka hi, low pass for the rest. Next ADCs perform 9 bit sampling frequencies up to 1.35 GHz, converting the full 500 MHz spectrum of all 12 pathways to digital data. It isn't specified in the drawings/patent, but it is assumed someone skilled in the art will know all 12 ADCs are part of a single DSP.

These outputs are inputs to the channelizers shown in figure 5, which as the first and most simple embodiment of the patent most likely represents the DSWM13. This stage creates the SWM channels by picking and choosing transponders from the 12 digitized 500 MHz bands. Thus the value of 'L' on the right side of figure 5 would be equal to 14 for the DSWM13 (13 SWM channels plus the guide channel)

For space reasons, on the left hand side of figure 5 only 2 of the 12 outputs from figure 4 are shown as inputs, but all 12 are actually used. There are 'k' pathways to the "select and reorder" stage for each of the 12 inputs, each pathway representing one transponder. Thus the number for 'k' will be different for the different paths, since not every 500 MHz band has the full complement of transponders active. The patent states that normally, k=16 for Ku and k=12 for Ka lo, which makes sense as the number of possible/typical odd or even transponders on Ku and Ka lo, respectively. It states that normally k=3 for Ka hi, which makes no sense, but I ascribe that to there being few Ka hi transponders being active when the patent was written. Clearly k=12 for Ka hi now for 103, and eventually for 99 when it D14 is in service.

The rest of the channelizer design is not documented, but given that it takes digital input from every 500 MHz band, and thus can select one or more individual transponders from any 500 MHz, then outputs stacked SWM channels on the other end I guess it is supposed to be pretty self explanatory for anyone who has understood everything up until this point  The "select and reorder" stage picks the required transponders containing the desired Directv channel(s), then frequency shifts them to be stacked in the SWM output. It isn't shown exactly where the conversion back to analog occurs, but probably after the circled plus so only one DAC is required to convert the whole SWM output.

I realize that to people not used to a DSP the idea of taking 12 500 MHz bands, each containing up to 12 or 16 transponders, and performing operations on 100+ transponders simultaneously is hard to wrap your head around, but that's exactly what this is doing. Just wait until the third embodiment, when it is doing these operations on all 1000+ Directv channels simultaneously!


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## veryoldschool (Dec 10, 2006)

JosephB said:


> I'm just confused why it was worth their time and money to build this when SWM8 and SWM16s are only in the range of $100, and that is the consumer cost at Solid Signal--DirecTV's cost has to be less than that.


The SWM8 was first used for MDUs.
The design moved to LNBs as cost savings over an LNB + WB68

While I have no inside info.... this new DSWM might follow the same path by becoming an LNB and be cheaper than a LNB + SWM-16


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## slice1900 (Feb 14, 2013)

JosephB said:


> Yeah, it seems if this is meant for hotels and whatnot, the 5 "bonus" tuners for the Genie wouldn't really make sense. In the end, how much more sense does this make than just using SWM-8 and SWM-16 modules? If you include the cost to develop this technology, along with the fact that there are DSPs and other more advanced technologies in this than a normal SWM, what do you get? I suppose you could modestly reduce the number of modules if you were loading racks with SWM-8s in a hotel or dorm or hospital type situation.
> 
> But, in an MDU it seems like this would be a bad choice. Generally one would think in a condo or apartment you're generally going to see fewer tuners per unit than single family homes, and with it being 13 tuners you now have an uneven balance if you were to split the single DSWM between two units. Plus, you have the need to isolate the MoCA networks between two units.
> 
> I'm just confused why it was worth their time and money to build this when SWM8 and SWM16s are only in the range of $100, and that is the consumer cost at Solid Signal--DirecTV's cost has to be less than that.


There was a paper on the ASIC used in the DSWM presented at ISSCC (a conference for people presenting about state of the art circuit design...Intel will present about their new CPUs there, for instance)

The paper stated there were two problems with the current SWM. One, that it didn't provide enough flexibility to increase the number of inputs (reference to the RDBS bands of D14 and D15, perhaps, or maybe some plans beyond that Directv hasn't shared yet) Two, that the SAW filters required in the design "significantly increase cost". In the patents figure 2 represents the current SWM, and 9 SAW filters are shown, one per channel. They are piezoelectric devices, not something you can shrink onto a circuit board, and I guess they must be pretty costly by comparison to integrated circuits.

I agree that 13 channels isn't really a big deal over 8 for MDUs, but it is still an improvement. The second generation should have 26, and the third even more, along with improvements that would provide IP output and drop the requirement for coax from DSWM to TV entirely if desired. The DSWM will be an evolution over time with regular improvements coming if they follow the path the patent lays out. So even if the DSWM13 isn't a huge improvement over the SWM8, it is just a step towards further improvements. The current SWM would always need one SAW filter per channel, limiting the cost improvement per channel that would be possible.

Certainly there would be no reason why anyone would want to rip out working SWM8s to replace with DSWM13s, but maybe when capacity is added DSWM13s would be added instead.

The cost/benefit of the DSWM13 might be hard to see at first - I'd guess they'll cost a lot more than a SWM8. That's probably why Directv is limiting it to certain markets for now, but perhaps they'll expand the market for it once they have the production cost driven down, or maybe they'll wait for the version with more channels (up to 26 would be possible in the second generation) before it sees wide deployment.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> The SWM8 was first used for MDUs.
> The design moved to LNBs as cost savings over an LNB + WB68
> 
> While I have no inside info.... this new DSWM might follow the same path by becoming an LNB and be cheaper than a LNB + SWM-16


If the SAW filters are as expensive as the paper seems to imply, it might eventually become the standard LNB deployed in new installs, similar to the SWM LNB today.

I don't suppose anyone would know what SAW filters cost when purchased in quantities of a million?


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## JosephB (Nov 14, 2005)

Down the line when it gets to the point that it's purely IP based, even from the LNB (or switch in the case of an MDU), what kind of bandwidth requirements and wiring requirements do you foresee? I'm guessing to guarantee QoS, the number of tuners supported would be determined by (speed of link)/(maximum theoretical channel bitrate)? Is there any idea at this point what that would be? IE: how many tuners would they be willing to install on a dedicated (no other traffic) 100Mb wired network?


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I'm quite certain it does exactly that.
> 
> I realize that to people not used to a DSP the idea of taking 12 500 MHz bands, each containing up to 12 or 16 transponders, and performing operations on 100+ transponders simultaneously is hard to wrap your head around, but that's exactly what this is doing. Just wait until the third embodiment, when it is doing these operations on all 1000+ Directv channels simultaneously!


I've read, thought, reread thought "a bunch more", over and over what you posted.

I think you've just described the digital filtering.

"In simple terms":
Analog in, frequency shift, ADC, digital filtering, DAC, frequency shift, analog out.


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> I'm quite certain it does exactly that. I'm not sure I understand your comment about how we're dealing with single wire coax. The output of the DSWM is single wire, but the input is the same legacy input that current SWM has. It is the input it is digitizing, outputting 13 SWM channels spaced more closely than current SWM to use the same or very similar frequency range. The drawings on the patents and the description itself is very clear that it does the following:
> 
> We can assume the legacy portion of an LNB is unchanged, or at least any changes are not referenced in these patents. The only change mentioned in the patents is the possible addition of feedback from the DSWM to tweak the DRO (dielectric resonant oscillator, or what we call a LO) frequency to correct for LO frequency drift.
> 
> ...


Wow ...

Thanks a much for this well written explanation. You've really helped my aging brain to understand this a lot better. Wish the patent description had been clearer on this for the main DSWiM parts as it was in quickly explaining the current ASWiM design which I grasped easily.

And yes I think the "k = 3" figure for the Ka-hi band is listed because D12 and of course D14 didn't exist when the patent was written and only SW1 & 2 operated in the Ka-hi band then with never greater of six (spotbeam) transponders in use.

3 LHCP and 3 RHCP , thus a "k" figure of only 3.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I agree that 13 channels isn't really a big deal over 8 for MDUs, but it is still an improvement. The second generation should have 26, and the third even more, along with improvements that would provide IP output and drop the requirement for coax from DSWM to TV entirely if desired.


The second generation would take a new receiver design, than what we have now.


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## slice1900 (Feb 14, 2013)

JosephB said:


> Down the line when it gets to the point that it's purely IP based, even from the LNB (or switch in the case of an MDU), what kind of bandwidth requirements and wiring requirements do you foresee? I'm guessing to guarantee QoS, the number of tuners supported would be determined by (speed of link)/(maximum theoretical channel bitrate)? Is there any idea at this point what that would be? IE: how many tuners would they be willing to install on a dedicated (no other traffic) 100Mb wired network?


Well, that all depends on the usable bit rate of a transponder. That in turn depends on what modulation scheme it uses and the amount of error correction ratio. Both of those could be adjusted over time, but let's make a WAG of somewhere between 1 and 2 Mbits per MHz. Maybe someone knows the real answer here?

If you have 12 500 MHz bands (they aren't all full, and not all transponders are fully utilized, but let's say they are) then that's 6000 MHz, or between 6 and 12 Gbps for everything, though of course even in the largest MDU not even close to all channels would ever be watched at the same time (unless the residents got together and tried a "flush all toilets at the same time" type of experiment on Directv ) Thus the output of all watched channels could easily be carried on a single cat6a cable running 10Gb ethernet.

Whether that 10Gb ethernet connection is available on a DSWM LNB or only on a DSWM switch, the MDU should need only the one. The DSWM would send the content via multicast so it would only require one copy of each watched channel, whether only one person is watching it or 100. Between that, and QoS, it is not a difficult problem network wise. These are both fairly mature technologies. The network cabling is no different than what a large MDU that provides ethernet to everyone would already have, or at least would certainly have by the time this was available.

In a home, you'd really need to have gigabit ethernet (which runs fine over ordinary cat5) as 100Mb would probably not hold enough channels for much more than a Genie's worth of tuners. Gigabit ethernet is super cheap now, and it will be impossible to find anything slower by the time you could get an IP DSWM LNB for the home. You'd be able to use wireless if you want, as that is already capable of speeds far in excess of 100 Mb, and even faster will be available in the future.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> The second generation would take a new receiver design, than what we have now.


Why? When discussing the second embodiment, the patent indicated that SWM has a maximum of 26 channels. If you do the math the current bandwidth used by the 8+1 channels would allow exactly 34 MHz each for 26+1 channels, not sure if that's where it came from but at any rate I wouldn't assume new receivers would be required.

Additionally, just because 26 channels is claimed as the limit doesn't mean they'd actually provide 26 channels if 26 was not compatible with current receivers but some smaller number still much larger than 13 was.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> Wow ...
> 
> Thanks a much for this well written explanation. You've really helped my aging brain to understand this a lot better. Wish the patent description had been clearer on this for the main DSWiM parts as it was in quickly explaining the current ASWiM design which I grasped easily.
> 
> ...


Cool, thanks! I figured the k=3 thing was something like that, I was racking my brain at first trying to understand that until I remembered that Ka hi was added after Ka lo 

In a real implementation I don't see why they would ever limit the k values, the only penalty for operating on non-existent transponders is a tiny bit of additional power/heat load as more area of the DSP is active. There seems to be little point in doing so and then later having to deliver a firmware update to them with new programming to increase the k value for bands that had transponders added to them.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Why? When discussing the second embodiment, the patent indicated that SWM has a maximum of 26 channels. If you do the math the current bandwidth used by the 8+1 channels would allow exactly 34 MHz each for 26+1 channels, not sure if that's where it came from but at any rate I wouldn't assume new receivers would be required.
> 
> Additionally, just because 26 channels is claimed as the limit doesn't mean they'd actually provide 26 channels if 26 was not compatible with current receivers but some smaller number still much larger than 13 was.


"I think" you're looking at what it "could do", but not how it will fit into the current line of TPs, since some are 50-60 MHz.
"If they were all 32 MHz", then...


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I've read, thought, reread thought "a bunch more", over and over what you posted.
> 
> I think you've just described the digital filtering.
> 
> ...


But that's all a SWM is, and the DSWM is just a digital version of a SWM, made to be cheaper by avoiding SAW filters and improved along the way to output 13 channels instead of 8. I know I confused things with my first few posts, just ignore those and only read the ones from yesterday evening on, after I'd actually read through the entire patent instead of skipping to the end for the good stuff - that IS where the good stuff was, but there are multiple embodiments and the DSWM13 will be only the first.

The first embodiment is a building block towards the path to a fully digital solution, but like you say it just does what the SWM8 does, only the transponder selection occurs in the digital domain instead of analog. The second embodiment builds on it by adding higher order functions (Hilbert transforms, Polyphase filters and Fourier transforms) for some of the processing. I believe that the output from that would be I/Q data for full transponders, which would allow placing SWM channels right up against each other with little or no guard band, thereby increasing the channel count to at or near the claimed 26 channel maximum. The third embodiment builds on that to allow operating "on fine pieces of spectrum" (which I take to mean individual Directv channels) The third embodiment shows several options, which ranges from SWM output (detailed in the patent as being two outputs, as on a SWM16) to IP output of I/Q data, to IP output of demodulated I/Q data (i.e., MPEG2/MPEG4)

The lack of clarity about exactly what the third embodiment will output may result from not quite being sure what product they wanted to arrive at when the patent was written. The first and second seem pretty clear, so I expect they were both well under development at the time this patent was written.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> "I think" you're looking at what it "could do", but not how it will fit into the current line of TPs, since some are 50-60 MHz.
> "If they were all 32 MHz", then...


I wasn't aware Directv had any different sized transponders for customer programming. I know they use some 250 MHz wide transponders for internal use.

I thought they were all 24 MHz or so wide for Ku and 36 MHz or so for Ka, with some guard bands around them. Which transponders are you referring to that are 50 to 60 MHz wide?


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> I wasn't aware Directv had any different sized transponders for customer programming. I know they use some 250 MHz wide transponders for internal use.
> 
> I thought they were all 24 MHz or so wide for Ku and 36 MHz or so for Ka, with some guard bands around them. Which transponders are you referring to that are 50 to 60 MHz wide?


From what I understand;

The Spaceway transponders in their "bent pipe" or "non-processor" mode are technically 62.5 MHz wide, but only the 36 MHz wide central portion of it is used (very inefficient). .

D10, 11, and 12 tps. (and soon the upcoming D14) are 36 MHz wide.

Ku band tps. are 24 MHz wide.

And the tps.for the World Direct international service from G3C at 95W are 27 MHz wide.


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## TheRatPatrol (Oct 1, 2003)

So is this new SWiM13 a new LNB that'll go on the dish and only have one cable coming out of it, like the current SWiM 8's? Or will it be more along the lines of the current SWiM 16's?


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## P Smith (Jul 25, 2002)

veryoldschool said:


> "I think" you're looking at what it "could do", but not how it will fit into the current line of TPs, since *some are 50-60 MHz*.
> "If they were all 32 MHz", then...


VOS, we did try to find such, but ... got only 36 MHz max, do you remember ?


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## slice1900 (Feb 14, 2013)

TheRatPatrol said:


> So is this new SWiM13 a new LNB that'll go on the dish and only have one cable coming out of it, like the current SWiM 8's? Or will it be more along the lines of the current SWiM 16's?


We can assume the DSWM13 Directv has announced isn't integrated into a LNB, since it is targeted at the MDU market. There will certainly be a DSWM LNB at some point, but when it will come and whether it will have 13 tuners or have more than 13 is unknown. I'd expect the announced DSWM13 to have a form factor and power requirement identical or nearly identical to the SWM8, since many products for the MDU market are designed specifically to hold multiple SWM8s.

There really isn't any reason for anyone to get too excited about DSWM yet, at least not to the point they think "I want one". It doesn't offer any benefits to the consumer over the current SWM anyone is yet aware of, aside from a few extra tuners. It won't have any effect on signal quality - the SNR is mostly set in stone in the LNB before it reaches the SWM/DSWM.

Speculation mode: ON
If I had to guess, I'd say we won't see a DSWM LNB until sometime next year, because I now feel fairly certain Directv will need a new LNB to receive everything on its upcoming D14 and D15 satellites. I'm starting to believe there's an outside chance we might see a whole new dish (for new installs only, the new LNB would work fine on the Slimline) Directv waiting a bit before integrating DSWM would have two benefits aside from waiting for the new LNB to be ready. One, the digital components in the DSWM get cheaper over time, and two, they might want to wait for the second generation version which will offer as many as 26 tuners. That would allow just about all residential installs to be done with a single wire.


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## HoTat2 (Nov 16, 2005)

TheRatPatrol said:


> So is this new SWiM13 a new LNB that'll go on the dish and only have one cable coming out of it, like the current SWiM 8's? Or will it be more along the lines of the current SWiM 16's?


If its to be used initially for MDU installs in D2 Advantage (formally MFH-2), or DRE systems targeted mainly for hotels, it has to be the stand alone module type first with a DSWiM-LNBF likely following sometime later for residential installs.

This will then largely replace the need for a SWiM-16 in many cases for residences which still require the age-old need of a cumbersome four coax line runs to its input that I'm sure DIRECTV would like to get almost totally away from that holdover characteristic of the legacy era.


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## peds48 (Jan 11, 2008)

slice1900 said:


> Speculation mode: ON
> If I had to guess, I'd say we won't see a DSWM LNB until sometime next year,


Well, that only gives you 8 weeks to be wrong and 52 to be right. the odds are on your side!


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## slice1900 (Feb 14, 2013)

peds48 said:


> Well, that only gives you 8 weeks to be wrong and 52 to be right. the odds are on your side!


OK, I'll amend that speculation, and say we will never see a DSWM LNB using the current stack plan, but a new LNB design using a new stack plan that will take into account all the new stuff like RDBS from 99/103 and Ka from 101. That's going out on a bit more of a limb...


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## damondlt (Feb 27, 2006)

I don't see the point of a swm 13.

Swm 16 is barely larger then a swm 8 now.
So unless directv is dropping swm 8's for 13's it seems pointless to me.


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## Diana C (Mar 30, 2007)

damondlt said:


> I don't see the point of a swm 13.
> 
> Swm 16 is barely larger then a swm 8 now.
> So unless directv is dropping swm 8's for 13's it seems pointless to me.


Just like the SWM-5 was a proving ground for SWM technology, the SWM-13 will be a proving ground for dSWM technology. You could very well see a SWM-13 being replaced with a larger version pretty quickly.

The ultimate version of this technology can be thought of as the tuner section of one or more Genies integrated into a "switch" sized device. The "receivers" will be little more than RVU clients, one or more of them with some storage attached. The SWM-13 is simply the first step down that path.


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## HoTat2 (Nov 16, 2005)

As was suggested earlier, unless DIRECTV feels the DSWiM-13 cost less to manufacture (no SAW filters, etc.) plus offers more SWiM channels to boot, over old standard of typically allocating 1 SWiM-8 per unit for MDU and the DRE installs. I would agree of not seeing the point to it.

The advantage of a future DSWiM13-LNB is more obvious though.


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## JosephB (Nov 14, 2005)

Diana C said:


> Just like the SWM-5 was a proving ground for SWM technology, the SWM-13 will be a proving ground for dSWM technology. You could very well see a SWM-13 being replaced with a larger version pretty quickly.
> 
> The ultimate version of this technology can be thought of as the tuner section of one or more Genies integrated into a "switch" sized device. The "receivers" will be little more than RVU clients, one or more of them with some storage attached. The SWM-13 is simply the first step down that path.


This would be *so great* if they'd use the technology to open up the TiVo development beyond a token contractually required box.


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## Diana C (Mar 30, 2007)

JosephB said:


> This would be *so great* if they'd use the technology to open up the TiVo development beyond a token contractually required box.


I wouldn't hold my breath for that! DirecTV has a financial disincentive to fully support TiVo - why split a DVR fee with TiVo when they can collect it all for themselves?


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## peds48 (Jan 11, 2008)

Diana C said:


> I wouldn't hold my breath for that! DirecTV has a financial disincentive to fully support TiVo - why split a DVR fee with TiVo when they can collect it all for themselves?


They don't necessarily "split" the DVR fee. matter fact, DirecTV collects both, their fee plus TiVO's


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## JosephB (Nov 14, 2005)

Right, getting a TiVo results in additional fees. I'm perfectly OK with that.


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## damondlt (Feb 27, 2006)

Diana C said:


> Just like the SWM-5 was a proving ground for SWM technology, the SWM-13 will be a proving ground for dSWM technology. You could very well see a SWM-13 being replaced with a larger version pretty quickly.
> 
> The ultimate version of this technology can be thought of as the tuner section *of one or more Genies integrated into a "switch" sized device*


I can plug in 3 genies into a swim 16, So again still don't see any point in a 13 Unless they are completely dropping the swm 8 and making a swm 13 LNB

For MDU, even a 13 is IMO sub par. 
I own a 3 apartment dwelling with Directv service and again would not cut the mustard.
It seems more suitable for a single family home, which would be more logical then just installing swm 8's in a Genie home.


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## damondlt (Feb 27, 2006)

HoTat2 said:


> As was suggested earlier, unless DIRECTV feels the DSWiM-13 cost less to manufacture (no SAW filters, etc.) plus offers more SWiM channels to boot, over old standard of typically allocating 1 SWiM-8 per unit for MDU and the DRE installs. I would agree of not seeing the point to it.
> 
> The advantage of a future DSWiM13-LNB is more obvious though.


I agree.


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## carl6 (Nov 16, 2005)

damondlt said:


> I can plug in 3 genies into a swim 16,


Not without some type of problem. The most you can get off either leg of an SWM 16 is 8 tuners. Only TWO Genies can be supported on an SWM16, which would leave 3 open tuner slots on each side of the 16, not enough for another Genie in either case.


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## damondlt (Feb 27, 2006)

carl6 said:


> Not without some type of problem. The most you can get off either leg of an SWM 16 is 8 tuners. Only TWO Genies can be supported on an SWM16, which would leave 3 open tuner slots on each side of the 16, not enough for another Genie in either case.


Sorry your right . :righton:
Swm 16
2 Genies, 2 HD DVRs and 2 HD receivers with whole home.

Swm 13 well if its one leg, the sure 2 genies one HD DVR and 1 HD receiver.

Sounds good, But again why bother, I find it hard to believe a SWM13 with the claimed specs. is going to be cheaper.

Build a swm 13 LNB and then maybe Directv will have something.

http://www.amazon.com/DirecTv-Channel-Multi-Switch-Inserter-PI29R1-03/dp/B003Z8TEF6/ref=sr_1_4?ie=UTF8&qid=1383833716&sr=8-4&keywords=directv+swm

A swm 13 better be about $30 with power inserter.


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## Ken Stomski (Nov 17, 2011)

At a Directv convention in April they hinted at having an unmanaged DRE system for hotels that had daisy chained wiring, verses each room having a home run to a closet which is what DRE requires now. How it works I have no idea but I will be finding out on the 19th. As it stands night now if you have daisy chained wiring the only thing I can install is a headend. I'm kinda excited!


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## veryoldschool (Dec 10, 2006)

Ken Stomski said:


> At a Directv convention in April they hinted at having an unmanaged DRE system for hotels that had daisy chained wiring, verses each room having a home run to a closet which is what DRE requires now. How it works I have no idea but I will be finding out on the 19th. As it stands night now if you have daisy chained wiring the only thing I can install is a headend. I'm kinda excited!


It would be interesting to hear what the plans are.
If you could replace the current splitter configuration with "SWiM approved" taps [directional couplers] daisy chaining shouldn't be a problem.


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## Ken Stomski (Nov 17, 2011)

veryoldschool said:


> It would be interesting to hear what the plans are.
> If you could replace the current splitter configuration with "SWiM approved" taps [directional couplers] daisy chaining shouldn't be a problem.


problem is, there are many hotels around here where the adjoining rooms share a drop with splitters buried in the wall behind furniture, and makes that option an upgrading nightmare. i believe this device is meant to be a work-around for this situation, to keep upgrading costs reasonable for hoteliers. I am getting schooled at 1pm next tuesday by P-10's engineers on this device. in related news, directv is allowing us to use zeevee to distribute HD via headend to non pro-idium televisions in non hotel-type places of lodging like nursing homes. That training starts at 9AM on the same day LOL.


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## slice1900 (Feb 14, 2013)

damondlt said:


> Sorry your right . :righton:
> Swm 16
> 2 Genies, 2 HD DVRs and 2 HD receivers with whole home.
> 
> ...


It won't be cheaper right away, because the production volumes for the ASIC will be small at first. Once they make a DSWM LNB, and it becomes the standard residential install, the production runs will be much larger and that should drive down the cost quickly. Some very complex chips can be made very cheaply if you make enough of them. For instance, its been estimated the A7 chip in the latest iPhone & iPad costs Apple about $15/each, and it is far more complex and made on a more advanced process than the ASIC used in the DSWM. If Directv orders production runs of a million at a time, as they would do, it'll cost only a few dollars - less than the 9 SAW filters that are no longer needed (based on what little info I was able to find about the range of pricing for high frequency SAW filters ordered in quantities of 10,000)

As I suggested earlier, I don't think we'll ever see a model that uses the current stack plan since it would make no sense to create a product that would be replaced so quickly. Instead the first DSWM LNB will add the ability to receive RDBS from 99/103 and Ka from 101, and maybe some future proofing beyond that. I doubt there will be a model that receives 110/119, so we'll have a "4 LNB" - or possibly "6 LNB" if they future proof for potential Ku band at 99 and 103. The longer it takes to appear the better the chances it will be introduced using the second generation DSWM, which would support as many as 26 tuners. That'll take care of all but 0.01% of residential installs.

The DSWM13 seems like it would be a good fit for MDUs in certain cases, because of the limitations of how they're installed with one wire run to an apartment. If someone had a couple DVRs and wanted to add a Genie, they'd have to disable tuners somewhere to make it fit, because the MDU isn't going to run a second coax just so one guy can have both legs of a SWM16. The DSWM13 would also make it more practical to share a single unit between two apartments (as is often done with SWM8s) even if both have Genies. Five more tuners may not seem like a big deal for residential, but I can see where it would be welcomed by MDUs to fix problems created by the Genie, even if it initially costs a lot more than a SWM8.


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## veryoldschool (Dec 10, 2006)

Ken Stomski said:


> problem is,


"I think you'll find"
They will be using taps and the SWiM will have a higher output level.
If a drop feeds two units, then the drop will be off a tap and the two units with a splitter.


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## damondlt (Feb 27, 2006)

> As I suggested earlier, I don't think we'll ever see a model that uses the current stack plan since it would make no sense to create a product that would be replaced so quickly. Instead the first DSWM LNB will add the ability to receive RDBS from 99/103 and Ka from 101, and maybe some future proofing beyond that. I doubt there will be a model that receives 110/119, so we'll have a "4 LNB" - or possibly "6 LNB" if they future proof for potential Ku band at 99 and 103. The longer it takes to appear the better the chances it will be introduced using the second generation DSWM, which would support as many as 26 tuners. That'll take care of all but 0.01% of residential installs.


If 13 and 26 will be the norms from here on out I say go for it.

A swim 13 would not work in my house, Because when Directv allows me to add another GENIE, that will put me at 15 tuners.
Swim 16 will do my future setup with no need for any additional equipment, unless there are some underlying issues with 2 genie on the same grid.
Don't see why there would be though.

Each output on the swm 16 Would have
1 Genie 1 HD DVR and one leg would also have 1 HD receiver, with still one more open tuner.


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## Diana C (Mar 30, 2007)

Even the first generation SWM 13 would make a lot of sense for MDUs where they are using multiple SWM 8s now. Even at the same per switch cost, the increased capacity would allow half as many SWM 13s. If the hardware cost comes down, the savings are even greater.


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## Diana C (Mar 30, 2007)

peds48 said:


> They don't necessarily "split" the DVR fee. matter fact, DirecTV collects both, their fee plus TiVO's


The deal that produced the THR22 was a lose-lose for everyone. TiVo makes so little money on the deal that they don't dedicate resources, the incremental cost to DirecTV doesn't get covered by increased revenue (so they basically ignore it), and the customers get a crippled device running 5 year old software.


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## peds48 (Jan 11, 2008)

Diana C said:


> The deal that produced the THR22 was a lose-lose for everyone. TiVo makes so little money on the deal that they don't dedicate resources, the incremental cost to DirecTV doesn't get covered by increased revenue (so they basically ignore it), and the customers get a crippled device running 5 year old software.


Why would this increase DirecTV cost? is not like they had to make a new receiver. they are using the HR22 for TiVOs


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## harsh (Jun 15, 2003)

peds48 said:


> Why would this increase DirecTV cost?



Marketing (as required by the contract)
Customer Support (for relatively few customers, but it still must exist)
warehousing and distribution
general ill will due to the outdated hardware and software
legacy hardware is more expensive to produce (moreso in limited quantities)


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## veryoldschool (Dec 10, 2006)

[mod hat on]
Not sure why Tivo has invaded this thread.
If needed Tivo posts can/will be split into another thread.
[mod hat off]

I think we're getting a fair idea of this new digital SWiM.
With digital filtering the channel spacing looks like it will be cut in half.

"I wonder why" only 13 channels?
Why not 16?

[Have no clue]
Could it be the 2.3 MHz FSK can't handle more? :shrug:


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## peds48 (Jan 11, 2008)

harsh said:


> Marketing (as required by the contract) Already in place
> Customer Support (for relatively few customers, but it still must exist) Already in place
> warehousing and distribution Already in place
> general ill will due to the outdated hardware and software Already in place
> legacy hardware is more expensive to produce (moreso in limited quantities) Already in place, no new hardware is being made


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## damondlt (Feb 27, 2006)

veryoldschool said:


> [
> 
> "I wonder why" only 13 channels?
> Why not 16?
> ...


Thanks . That is the best answer yet.

That's makes me wonder more if the above is true, I can't see and easy or cheap SWiM 26.


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## P Smith (Jul 25, 2002)

veryoldschool said:


> ...
> Could it be the 2.3 MHz FSK can't handle more? :shrug:


it come to 230 Kbps bitrate in worst case scenario of coding or up to 2 Mbps ... you think it's not enough to control switching by short cmds ?


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## veryoldschool (Dec 10, 2006)

P Smith said:


> it come to 230 Kbps bitrate in worst case scenario of coding or up to 2 Mbps ... you think it's not enough to control switching by short cmds ?


This is one of those "I just don't know".

DECA has a node limit, so I wonder if the original FSK was structured with one too? :shrug:

It seems reasonable that "on the hour" all the receivers could be sending commands at the same time.


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## P Smith (Jul 25, 2002)

it would be interesting to log all the cmds with time-stamps; perhaps best spot for that is a controller inside of SWM switch ...


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> [mod hat on]
> Not sure why Tivo has invaded this thread.
> If needed Tivo posts can/will be split into another thread.
> [mod hat off]
> ...


Clearly that's not the case, or the patent wouldn't suggest the second embodiment (second generation) of the device squeeze the transponders together more closely to add more channels beyond the 13 in the first embodiment, nor would it clearly state that this device would use a 32 point FFT "despite a maximum of 26 channels". Using FFT and other digital "tricks" it will be possible to stack transponders right on top of one another with no guard band, and while it isn't explicitly stated that's certainly what they seem to be implying they're doing. 26 channels * 36 MHz = 936 MHz _fits_ and 972 MHz does not. Even if they don't follow the "roadmap" laid out in this patent, clearly the authors know exactly what the limitations are and wouldn't suggest something like that if FSK was going to put a much lower bound on the number of channels.

The FSK isn't even limited to 26 channels, as the third embodiment that uses "finer pieces of spectrum" (which I take to mean individual channels) will support "many more [SWM] channels". Depending on whether it used a fixed layout based on the largest possible channel or used the space the channel actually consumed, you might have "only" 50 channels (using spacing for some big fat 4K channel) or hundreds of channels (if all were tuned to SD programming)

I've never really known where the 974 MHz start of SWM came from (why not 950?) or even what that number is. Is it the start of the guard band, start of the transponder, channel center, or what? I've always been suspicious that Ku (i.e. guide channel) transponders are 24 MHz wide, and 950 + 24 = 974, but... I don't suppose anyone has ever posted photos of what SWM looks like in a frequency analyzer? The patents for the original SWM I found suggested that transponder placement wouldn't be exact. Perhaps 974 MHz is center frequency, thus a 36 MHz Ka transponder would start at 956 MHz, but they wanted to leave a little room for error to make sure it could never end up being below the tuner's bottom at 950.

So let's assume for the moment 974 is center frequency and play with the numbers a bit and see where they take us. If you add 936 MHz to it and account for center frequency, you have a maximum SWM frequency of 1892 MHz. So that made me think - the H23 used a wideband tuner capable of tuning from 250 - 2150 MHz so no BBC was required, but that was dropped in the H24 because it proved too expensive. I wonder if there are some savings from reducing the top end of a tuner, and maybe the SWM only H25 and Genie have a tuner that's only capable of hitting 1900 MHz rather than 2150 MHz as a cost cutting measure (kind of important in the Genie when it has five tuners) Can anyone comment on that? Is there some merit to this argument or is cutting a mere 250 MHz off the high end going to make almost no difference in the cost of a tuner?

One other interesting thing I found in those old patents is the suggestion that SWM could vary the gain between channels depending on the receiver's needs, I assume by the receivers reporting signal strength for their channel. This was presumably never implemented, but it would be very useful in a DSWM with many channels, since you'd be splitting the signal dozens of ways.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Clearly that's not the case....
> 
> I've never really known.....
> 
> So let's assume....


I don't know that the FSK is a reason, but I have seen "something" [which I can't share] that suggests some limitation.

Once again, you're chasing/following patents and I'm looking at things more from what is and how things can change/improve while still working with what is out there now.

"Great ideas" sometimes don't always make it through testing.

Time will tell, and "so far" there seems to be a fairly good idea of what this new DSWM13 will be.

What the next model will be is a bit far away.


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## P Smith (Jul 25, 2002)

regarding using FFT, stacking transponders w/out guard gap ... sounds good but it wouldn't be practical for an implementation as existing receiver's tuner(s) still based on old solution what is _REQUIRE_ the gaps


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## slice1900 (Feb 14, 2013)

P Smith said:


> regarding using FFT, stacking transponders w/out guard gap ... sounds good but it wouldn't be practical for an implementation as existing receiver's tuner(s) still based on old solution what is _REQUIRE_ the gaps


When tuning legacy bands receivers sure don't require much of a gap. There is only 5 MHz spacing between Ku transponders and 4 MHz spacing between Ka transponders. I don't know if that is done more for the benefit of the sender or receiver, but there is certainly no requirement for anything remotely like the kind of guard bands SWM uses now, or the DSWM13 is using. We can speculate what design or component constraint caused current SWM to use 102.06 MHz wide channels for 24/36 MHz wide transponders, but we all know the answer boils down to "Directv wanted to minimize cost".

I don't know if this can be generalized to the type of high frequency L band tuners satellite receivers use, but lower frequency tuners are capable of tuning NTSC, ATSC and CATV QAM in the range of 50 - 750 MHz, despite those having no guard bands at all. They work just fine. Clearly tuners do not inherently require a guard band, at least not tuners operating below 1 GHz.


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## P Smith (Jul 25, 2002)

I think you are not right; filtering w/out gap would reduce SNR ratio to unacceptable level by getting signals of adjusted station(s);

OTA station has the gap - just fire any spectrum analyzer, it would be easy recognized by naked eye (I did while tuning different models of OTA antennas in different freq and directions )


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> When tuning legacy bands receivers sure don't require much of a gap. There is only 5 MHz spacing between Ku transponders and 4 MHz spacing between Ka transponders..
> 
> I don't know if this can be....


I suggest you spend more time with filters.
The skirts are why "gaps" are needed.
The digital filters are better than the SAWs, but the tuner chip in the receivers isn't digital or SAW.
NTSC used 2 MHz.



P Smith said:


> I think you are not right; filtering w/out gap would reduce SNR ratio to unacceptable level by getting signals of adjusted station(s);
> 
> OTA station has the gap - just fire any spectrum analyzer, it would be easy recognized by naked eye (I did while tuning different models of OTA antennas in different freq and directions )


You once posted a screen shot of the SA looking at the SWiM channels.
If you could find it, it will show why 101 MHz spacing was used with the SAW filters as they weren't "sharp enough" to block part of the adjacent TP energy and there were "humps" between the channels.


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## P Smith (Jul 25, 2002)

veryoldschool said:


> I suggest you spend more time with filters.
> The skirts are why "gaps" are needed.
> The digital filters are better than the SAWs, but the tuner chip in the receivers isn't digital or SAW.
> NTSC used 2 MHz.
> ...


here is http://www.dbstalk.com/topic/154920-swm-16-in-the-works/page-7#entry3126887


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## gov (Jan 11, 2013)

Probably a dumb question, but here goes:

How many HD channels can a cable TV outfit cram into 500 MHz ?

Boocoo!


Why are the numbers so much smaller in the SWM world ?


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## veryoldschool (Dec 10, 2006)

P Smith said:


> here is http://www.dbstalk.com/topic/154920-swm-16-in-the-works/page-7#entry3126887


Here's a bit of photoshop to show the old and new channel layout along with the limitation of the SAWs


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## veryoldschool (Dec 10, 2006)

gov said:


> Probably a dumb question, but here goes:
> 
> How many HD channels can a cable TV outfit cram into 500 MHz ?
> 
> ...


I just checked comcrap and came up with about 100.
They reduce the resolution to cram more in the bandwidth.

DirecTV's bandwidth equals "about" 3x cable, and why the LNBs either need to switch or be "preselected" [SWiM] to be on one coax.


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## RAD (Aug 5, 2002)

Don't forget that cable can also use Switched Video Service. No need to send out every HD channel to everyone at the same time, only send out the channel to the person that wants to view it to squeeze more channels into limited bandwidth.


Sent from my iPad using DBSTalk


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I suggest you spend more time with filters.
> The skirts are why "gaps" are needed.
> The digital filters are better than the SAWs, but the tuner chip in the receivers isn't digital or SAW.
> NTSC used 2 MHz.
> ...


NTSC uses much more than 2 MHz. It does appear however that it uses a 250 KHz guard band.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> NTSC uses much more than 2 MHz. It does appear however that it uses a 250 KHz guard band.


Actually it needed much more:
"Analog stations must be separated by at least one unused channel except for non-adjacent channel pairs 4 and 5, 6 and 7, and 13 and 14."

ATSC can have adjacent, but still needs a small gap/guard









You can see in the photo of the SA that the transponder "skirts" are wider so their "gap" will need to be more than an ATSC channel.
Since SATMUX is used on the TP, selecting "a channel" at the receiver takes more bandwidth.


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## slice1900 (Feb 14, 2013)

gov said:


> Probably a dumb question, but here goes:
> 
> How many HD channels can a cable TV outfit cram into 500 MHz ?
> 
> ...


SWM puts the whole transponder containing the single channel you want in a SWM channel, then wraps it in a huge guard band. It very wasteful, and could be done better, but it was clearly designed more with cost in mind than doing the best that could possibly be done. Directv has to pay for this to be done for every customer, while the cable company only has one headend per city. So they can clearly afford to pay a lot more for the headend to be efficient with its use of bandwidth than Directv can for SWM to be efficient with its bandwidth. The DSWM patent suggests a path where the DSWM13 is just the start, made possible in a cost effective manner similar to how it has greatly improved the capabilities of cell phones over the past decade.

Rather than comparing with SWM, which isn't the same thing at all, it would be better to compare how many HD channels cable can fit in 500 MHz versus how many satellite can fit in a single 500 MHz band containing 12 Ka transponders (432 MHz usable) Even there, satellite obviously requires a lot more error correction coding, and uses different modulation schemes that aren't as dense as QAM-256.

On the other hand, a satellite receiver can pick up a signal of -60 dbm or lower with a SNR of only 7 or 8 db. A cable receiver requires far more signal power, and loses picture when SNR drops as low as 20 db! If cable used simpler modulation schemes it wouldn't need such a high SNR, but it wouldn't be able to squeeze in as many channels.


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## JosephB (Nov 14, 2005)

gov said:


> Probably a dumb question, but here goes:
> 
> How many HD channels can a cable TV outfit cram into 500 MHz ?
> 
> ...


Cable is a lot more complicated than that, though. First, there's SDV which anecdotally I've seen some places have half of their HD lineup or more be SDV. Plus, most cable plants are like 750-800mhz, not 500mhz. Some systems (like Cox) are moving all the way to 1Ghz in their systems.

Also, some cable systems (again, mostly Cox) are doing MPEG-4, but most do MPEG-2. Then, you have to pile on top of all of that the bandwidth they dedicate to internet and telephone services.

According to Wikipedia: "38.47 Mbit/s using 256-QAM on a 6 MHz channel....Each 6-MHz channel is typically used to carry 7-12 digital SDTV channels (256-QAM, MPEG2 MP/ML streams of 3-5 Mbit/s)"

Most cable systems are 256-QAM, and that is also the modulation and channel usage for DOCSIS (a single channel DOCSIS modem gets 38mbit/sec, usually provisioned to the customer at 30mbit/sec)


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Actually it needed much more:
> "Analog stations must be separated by at least one unused channel except for non-adjacent channel pairs 4 and 5, 6 and 7, and 13 and 14."
> 
> ATSC can have adjacent, but still needs a small gap/guard
> ...


Ah yes, I forgot how few channels we had when I was a little kid until we got cable! So NTSC had almost no guard band, but relying on the FCC to not approve adjacent channels gave it effectively a 6 MHz guard band.

From this plot, it appears ATSC is using a bit over 0.6 MHz guard band. Directv uses a 4 MHz guard bands on the Ka transponders, which are 36 MHz wide. So the larger guard band Directv uses is due to the larger "skirts"? Are those skirts an artifact of transmitter inefficiency, imperfect filters, or something else? If it were possible to miminize the skirts like ATSC does, would the tuner be able to use ATSC sized guard bands instead or is there some other reason a satellite tuner would still need larger guard bands than that?


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## slice1900 (Feb 14, 2013)

JosephB said:


> Cable is a lot more complicated than that, though. First, there's SDV which anecdotally I've seen some places have half of their HD lineup or more be SDV. Plus, most cable plants are like 750-800mhz, not 500mhz. Some systems (like Cox) are moving all the way to 1Ghz in their systems.
> 
> Also, some cable systems (again, mostly Cox) are doing MPEG-4, but most do MPEG-2. Then, you have to pile on top of all of that the bandwidth they dedicate to internet and telephone services.
> 
> ...


Not every cable system uses SDV. Mine doesn't.

QAM256 provides twice the bitrate of ATSC's 8VSB, so you can get two ATSC quality channels per QAM256 channel, or three pretty good ones. If a cable company devoted 500 MHz to HD channels only that would be about 250 "pretty good quality" HD channels, or 165 ATSC quality channels. That's a pretty reasonable amount of bandwidth to devote to HD for those that have eliminated analog entirely, though I don't think many have (mine still has 27 analog channels left (1-22 & 95-99)


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Ah yes, I forgot....
> 
> From this plot, it appears ATSC is using a bit over 0.6 MHz guard band. Directv uses a 4 MHz guard bands on the Ka transponders, which are 36 MHz wide. So the larger guard band Directv uses is due to the larger "skirts"? Are those skirts an artifact of transmitter inefficiency, imperfect filters, or something else? If it were possible to miminize the skirts like ATSC does, would the tuner be able to use ATSC sized guard bands instead or is there some other reason a satellite tuner would still need larger guard bands than that?


I think you're starting to ask the right questions.
The tighter you want everything to work, the more it's going to cost.
I measured an LNB that was just over 3 MHz off frequency.
There were a few batches of SWiMs that when they got "real cold" would have the receiver drift to the adjacent channel and then back.

The new DSWM channel spacing "could have" about 23 channels, but it's limited to 13 + guide.
I don't no the reason, as I've said before, but I do wonder about the FSK signal as its design/spec is about 10 years old, to work with what was called at the time FTM, and only needed to work with 8 tuners.


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## slice1900 (Feb 14, 2013)

OK, so given that some type of guard band is required, and probably can't be avoided, the 26 channel limit can't be due to having to fit within the current SWM frequencies, because 26 channels won't fit with any sort of guard band. Assuming the H25 and Genie have tuners capable of the full 950 - 2150 MHz that the tuners in the other receivers do, there would be no reason not to use the full range, or at least a higher range. Possibly some very marginal in-wall cabling or splitters could render the highest channel frequencies inoperative despite current SWM working due to its lower top frequency - but the highest channels would very rarely be used in a 26 channel SWM outside of commercial/MDU markets where the installation quality and components are (hopefully) better controlled.

If we use the 4 MHz guard band Ka satellites do, 26 channels start at 950 MHz and go to 1990 MHz. 27 channels would go to 2030 MHz (it isn't clear whether the "maximum of 26 channels" statement includes the guide channel or not) To use the full range we could use a 10 MHz guard band with 26 channels, or 8 MHz with 27.

The comment about the 26 channel limit is interesting, but without knowing more we can't make any real conclusions about where it comes from, but it is either some sort of hard limit in a transponder at a time scheme or the initial design of this second embodiment was already underway when the patent was written and 26 channels was the most that would fit given the size of the guard band they used.

It is clear however that 26 channels is not the limit of the SWM protocol, FSK or the receivers, but only a limit when using what the patent calls "the coarse granularity design" (i.e. transponder at a time) since the patent claimed the third embodiment using "finer pieces of spectrum" will "provide more channels using the same physical bandwidth".


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I think you're starting to ask the right questions.
> The tighter you want everything to work, the more it's going to cost.
> I measured an LNB that was just over 3 MHz off frequency.
> There were a few batches of SWiMs that when they got "real cold" would have the receiver drift to the adjacent channel and then back.
> ...


Interestingly, there was a second DSWM patent that includes frequency drift correction that feeds back to the DRO to correct for the temperature or age related frequency drift. If implemented, you wouldn't see those cold batch problems again.

Is LNB failure typically the result of frequency drift problems, or are there other failures? They seem to typically be intermittent failures, sometimes random and sometimes correlated with temperature. If frequency drift is a common cause of LNB replacement, this would be a good way for Directv to save a lot of repair calls.

Just to make it clear, when I'm talking about the 26 channel limit, I'm talking about what the patent said for the _second_ embodiment of the DSWM design. The first embodiment describes a simple design that uses no higher order digital operations, and this is likely what the DSWM13 is. There's no reason they can't do a 13 channel version now, and a (up to) 26 channel version later.

You can usually tell when patents describe something that's already been done or is in the process of being done, and when they're describing stuff that's still on the drawing board, or haven't even made it that far. The first and second embodiment read like something they've already built, and the third embodiment reads like something that's still on the drawing board, since it is not as precise and presents multiple options. It reads a lot like the patents for the original SWM I was able to dig up, which present multiple options such as ones that included full tuners in the SWM.

I expect to see the second embodiment fairly soon on the heels of the DSWM13. It needs a more powerful ASIC to implement all the higher order math, which time takes care of thanks to Moore's Law.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Interestingly, there was a second DSWM patent that includes frequency drift correction that feeds back to the DRO.
> 
> Just to make it clear, when I'm talking about the 26 channel limit, I'm talking about what the patent said for the _second_ embodiment of the DSWM design.
> 
> I expect to see the second embodiment fairly soon on the heels of the DSWM13. It needs a more powerful ASIC to implement all the higher order math, which time takes care of thanks to Moore's Law.


I'm not sure what your "fairly soon" is, but the second embodiment might need Moore's Law for the digital filtering to be more than 9 bit, so the filter can match the transponder bandwidth closer, and still be at a "reasonable cost".

Early on I think you might have gotten a "bit carried away" with your ideas of the third embodiment.

Since the first embodiment uses less frequency range than the current SWiM, I'm waiting to find out why it isn't a DSWM15 or 16, as cost shouldn't be a reason.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I'm not sure what your "fairly soon" is, but the second embodiment might need Moore's Law for the digital filtering to be more than 9 bit, so the filter can match the transponder bandwidth closer, and still be at a "reasonable cost".
> 
> Early on I think you might have gotten a "bit carried away" with your ideas of the third embodiment.
> 
> Since the first embodiment uses less frequency range than the current SWiM, I'm waiting to find out why it isn't a DSWM15 or 16, as cost shouldn't be a reason.


This reasoning behind the 9 bit sampling is directly addressed in the patent text, which is claimed to be sufficient based on some math involving signal quantization ratio I don't pretend to understand. It is even suggested the use of fewer than 9 bits may be possible. I've copied it below, perhaps you can make more sense out of it than I did.

Do we know the DSWM13 uses a smaller frequency range? What range/channel centers is it using? If someone posted something that shows the channel layout it is using, I certainly missed it...or is this non-public info that you saw but can't repost? The number of channels in the first and second embodiment is shown as 'L', implying it is a quantity that can vary, but which is stated to be limited to 26 channels unless "finer pieces of spectrum" are used as opposed to entire transponders.

I don't know why they would use a smaller frequency range in the DSWM13 than in current SWM, if that's indeed the case, when they could have fit in more channels. Maybe the reason will become apparent when the second generation DSWM makes its appearance, if they do introduce a DSWM26 maybe 13 was just chosen because its half? :shrug: The answer to "why 13" is as much a mystery at this point as "why is 26 claimed to be the limit". All I can say is that I think it was smart not giving it 16 channels, since that would potentially create a lot of confusion!



> Consider any one of the 500 MHz LNB signals 406-428. Since each signal is a composite of many signals, each signal is approximately Gaussian distributed. Given this approximation, the attack point on the ADC can be set so that the full scale deflection is 3.3 times the Root Mean Square (RMS) value of the composite signal. This corresponds to setting the probability at a 3.3 sigma event. This will result in a probability of overflow of 10-3. Under these conditions, the Signal to Quantization noise Ratio (SQR) is (6.02b+0.42) dB where b=ENOB-1. For an A/D with and ENOB of 9 bits this results in an SQR of the composite signal of 45.58 dB [I think he meant 48.58 here]. The SQR of a single transponder, in a twelve transponders mix with five high power transponders and seven low power transponders, where a high power transponder is 10 dB higher than a low power transponder. A given low power transponder then accounts for 1/57th of the composite power, or -17.56 dB from the composite power. The transponder's Noise Equivalent Bandwidth at the receiver is 36 MHz. Quantization noise is essentially white noise over the Nyquist bandwidth. If the Nyquist bandwidth is set to 500 MHz for the composite bandwidth, then the noise BW affecting the transponder is 36/500, which is -11.43 dB down from the total quantization noise. Therefore the SQR affecting the demodulator is 48.58-17.56+11.43=42.45 dB. Since the 8PSK waveform typically has an Signal to Noise Ratio (SNR) requirement of approximately 11 dB, an ENOB of 9 bits is typically satisfactory in terms of design. However, an accounting of the NPR of the finite word processing and additional details of the noise bandwidth and system settings may allow the ENOB to be relaxed from a 9 bit setting and still be within the scope of the present invention.


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## inkahauts (Nov 13, 2006)

Someone asked ages ago why i think the process of putting to bed mpeg2 wont start till we see dswm, and its because if the third idea in the patents require new tech in the receivers and can be done, I think they'd wait for that to hit before bothering. Plus it sounds like this tech may be cheaper than the old stuff soon enough.

I still think it may have to do with pricing and testing just as the swim 5 did as many here have speculated. I think and hope the dswim13 will come and go as fast as the swim5 did. It will be very nice to have at least a dswim13 lnb though. That I have a feeling would drastically lower costs over all for Directv.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> This reasoning behind the 9 bit sampling is directly addressed in the patent text, which is claimed to be sufficient based on some math involving signal quantization ratio I don't pretend to understand.


"Don't feel like the Lone Ranger" :lol:
Before this thread, I only knew there were digital filters and nothing about them.
Right after my post about the 9 bit, I thought a bit and it might be increasing the sample rate instead.
"I'd guess" to make a better filter, you either need more bits, or to sample more, but either way, it's more "number crunching" [aka processing power].

I'm not going to try to pares what I can or can't say, other than:
The new channel spacing is half the current spacing.
Therefore without two times the channels, less frequency range [bandwidth] is beings used.


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## harsh (Jun 15, 2003)

peds48 said:


> > Marketing (as required by the contract) Already in place
> > Customer Support (for relatively few customers, but it still must exist) Already in place
> > warehousing and distribution Already in place
> > general ill will due to the outdated hardware and software Already in place
> > legacy hardware is more expensive to produce (moreso in limited quantities) Already in place, no new hardware is being made


With the possible exception of the THR22 hardware (assuming that all they'll ever need have already been manufactured), all of these are ongoing costs so your "already in place" argument doesn't really apply.

I think there's a non-negligible chance that TiVo-based users might rightly be concerned that their hardware might suffer interoperability issues (at least initially) with a new product such as the DSWM13.


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## veryoldschool (Dec 10, 2006)

harsh said:


> With the possible exception of the THR22 hardware (assuming that all they'll ever need have already been manufactured), all of these are ongoing costs so your "already in place" argument doesn't really apply.
> 
> I think there's a non-negligible chance that TiVo-based users might rightly be concerned that their hardware might suffer interoperability issues (at least initially) with a new product such as the DSWM13.


OK last time for Tivo in this thread!

I doubt THR22 would have problems with the DSWM13, since it works with the current SWiM.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> "Don't feel like the Lone Ranger" :lol:
> Before this thread, I only knew there were digital filters and nothing about them.
> Right after my post about the 9 bit, I thought a bit and it might be increasing the sample rate instead.
> "I'd guess" to make a better filter, you either need more bits, or to sample more, but either way, it's more "number crunching" [aka processing power].
> ...


OK, I'm probably overthinking this because I know exactly what you're suggesting, I just don't know exactly what you were told or what you know 

There are two ways to interpret "half the current spacing". Half the spacing between transponder centers, or half the spacing _between transponders_. The patent explains current SWM grabs a 40 MHz wide transponder (I guess it takes a bit more than the actual 36 MHz max in case the frequency is shifted a bit) and we know it is then placed in channels separated by 102.06 MHz, for a total of 918.54 MHz current SWM bandwidth.

Using the first interpretation of "half the spacing", instead of 102.06 MHz between transponder centers you have 51.03 MHz between centers, and use only 714.42 MHz SWM bandwidth, as you imply.

Using the second, instead of 62.06 MHz of unused space between transponders you have 31.03 MHz unused space, and 994.42 MHz SWM bandwidth is used - slightly more than current SWM.

Assuming I'm overthinking and its using only ~50 MHz per SWM channel, it does beg the question of why they wouldn't have added more channels. Maybe this is the SWM5 of the DSWM line as inkahauts suggests, destined for a short life and intended more as a proving ground before its big brother comes next year. There are also some chip fabrication reasons why it might be using fewer channels than it was originally designed for. If the ASIC was not yielding well, some capacity that was designed in might be unused. That is, if you have 30% of your chips that worked for a designed in capability of let's say 18 channels but 80% of them work if you only require 13 channels, you'd make them all 13 channel models. It often takes several respins to work out the yield and other issues. Particularly since Directv's team may not have experience working on an ASIC like this.

Possibly the ASIC used in the DSWM13 actually implements second embodiment from the patent, but only uses limited functionality when installed in the DSWM13 as they finish the software and tweak/fix the hardware. Now that I think about it, that may be the most cost effective way for them to manage this project. The "better" chips that come off the line are used internally for testing the second generation DSWM, and the rest are put into the DSWM13 so they can be put to some useful purpose. If so, the channel spacing used in the DSWM13 would be used in its replacement, which implies they wouldn't quite make 26 channels - 51.03 MHz spacing would only allow for a DSWM22, though yield may drop that further.


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## TheRatPatrol (Oct 1, 2003)

Could D* come out with a LNB mounted SWiM 16 if they did away with the 72/95 inputs and the legacy outputs, with just two cables come out of the LNB?


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## slice1900 (Feb 14, 2013)

They could, but if they were going to do they would have done it ages ago. How would it really be any different than mounting the SWM16 at a legacy dish and running its two outputs inside? I'm sure some installs are done that way to avoid having all 4 cables running inside.


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## TheRatPatrol (Oct 1, 2003)

slice1900 said:


> They could, but if they were going to do they would have done it ages ago. How would it really be any different than mounting the SWM16 at a legacy dish and running its two outputs inside? I'm sure some installs are done that way to avoid having all 4 cables running inside.


True. Was just thinking it would be two less cables to run and one less thing to install. It would make for quicker installs.


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## JosephB (Nov 14, 2005)

TheRatPatrol said:


> True. Was just thinking it would be two less cables to run and one less thing to install. It would make for quicker installs.


The situations where it would be "easier" to have it in the LNB are probably outnumbered by the situations where they need the flexibility of having the switch external (such as powering multiple SWM 16s off one dish, etc)


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## peds48 (Jan 11, 2008)

slice1900 said:


> They could, but if they were going to do they would have done it ages ago. How would it really be any different than mounting the SWM16 at a legacy dish and running its two outputs inside? I'm sure some installs are done that way to avoid having all 4 cables running inside.


Well, this is really frown upon

And is also not up to code because the coax(s) are supposed to be grounded before the switch. so unless the switch is within 20 feet of the ground source, this won't pass muster


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## slice1900 (Feb 14, 2013)

Why in the world would the "code" care about grounding coax before versus after a SWM16? You ground coax before it enters the structure, the NEC doesn't have any language that prevents this happening after a switch (or, similarly, after an OTA antenna's preamp)

How would grounding the SWM16's outputs be any different than grounding a SWM LNB's output? Perhaps Directv requires installers ground coax before a SWM16, but if so it has nothing to do with the code and makes no sense at all.


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## peds48 (Jan 11, 2008)

"code" says it has to be grounded before the power inserter


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## slice1900 (Feb 14, 2013)

The PI is still inside the house, isn't it? Or do you mean the place where the PI connects to? In which case a SWM LNB, or for that matter even a regular LNB would be in violation.

And please show me where in the NEC it says anything that could be interpreted to state what you claim.


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## JosephB (Nov 14, 2005)

slice1900 said:


> The PI is still inside the house, isn't it? Or do you mean the place where the PI connects to? In which case a SWM LNB, or for that matter even a regular LNB would be in violation.
> 
> And please show me where in the NEC it says anything that could be interpreted to state what you claim.


I would assume that he's implying that the PI is supposed to be within 20 feet of the switch.


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## veryoldschool (Dec 10, 2006)

I'm going to throw out some guesses:

The DSWM13 is going to be short lived much like the SWM5 was.

We'll see a DSWM13 LNB.

We'll see a DSWM with around 20 or more for MDUs.

The SWM-32 could be replaced with a DSWM with around 90.

Output power will increase to support 400' runs.


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## slice1900 (Feb 14, 2013)

I agree with you, except I think the DSWM LNB will use the second generation version with 20-26 tuners, not the first generation with 13.

It'll be interesting to see if they release a third generation DSWM with stacked output, or if they go directly to IP. Having many more tuners per coax in an MDU implies that not only do they need to support a lot more length (to cover to the distance to many more apartments per SWM than used to be possible) but also to split it at least 128 ways. Since they'll be sharing the stacked cable between many apartments, maybe they would develop splitters with integrated BSFs in each port for splitting between apartments.

The first generation SWM patents had among their claims the idea of controlling the gain of each channel separately depending on what the receiver designated that channel required. Obviously that wasn't implemented, but maybe it would be implemented in this generation. I think something like this would almost be a requirement if you want to split 128 ways and support hundreds of cable feet from the DSWM. Only problem is that the third generation DSWM shares SWM channels between receivers, though there ways around that problem.


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## veryoldschool (Dec 10, 2006)

Splitting 128 ways "I doubt" we'll see.
Using taps [directional couplers] would allow better [more efficient] power distribution.


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## slice1900 (Feb 14, 2013)

That's a good point, since the 3rd gen DSWM would only be used to its fully capability in MDUs, it would be advantageous to distribute its output in a similar manner to how trunklines are distributed. I guess the feasibility of doing so in an existing MDU would depend on how it had been designed. Sonora's designs seem to assume all SWM lines being distributed from a single point on each floor (unless perhaps the floor is bigger than SWM's distance limit and maybe you need a horizontal branch trunk?) This layout would make for no difference between tapping versus splitting, but not all MDUs are necessarily designed that way. Even in such cases, a single 20 db amp would solve the problem of less optimal signal distribution so I suppose it doesn't really matter.

I keep coming back to the idea that doing it via IP would make the most sense for greenfield MDU deployments since there is no signal loss to worry about and far less infrastructure to build out. No trunk lines, no amps, no taps, no splitters, no nothing. It would cost less even if you built out an entirely separate network for it. You'd need new receivers unless more recent ones were designed to receive I/Q via IP, but even if not it would cost almost nothing to build that capability into future receivers. The Genie already bridges between the tuner and network, perhaps that was the result of the communication that would be required between the two and it is already capable of this?


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> .... I keep coming back to the idea that doing it via IP would make the most sense for greenfield MDU deployments since there is no signal loss to worry about and far less infrastructure to build out. No trunk lines, no amps, no taps, no splitters, no nothing. It would cost less even if you built out an entirely separate network for it. You'd need new receivers unless more recent ones were designed to receive I/Q via IP, but even if not it would cost almost nothing to build that capability into future receivers. The Genie already bridges between the tuner and network, perhaps that was the result of the communication that would be required between the two and it is already capable of this?


I would agree with this except for the fact that I'm sure a lot of this same reasoning here helped motivate the development of the IP based MFH-3 which has now been discontinued and during its lifetime frequently maligned as an "IP mess," "disaster," or some other such verbiage.

The third embodiment appears much the same idea as MFH-3 as far as IP distribution part is concerned, but with a decentralized and distributed head end to the DSWiM units.

Would such a decentralization of the head end to individual DSWiMs serving the floors of an MDU solve the problems that led to MFH-3's demise?


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## slice1900 (Feb 14, 2013)

I only know a limited amount about MFH3, and it would surely be interesting to hear the viewpoint of an installer who has worked with it. I'm sure that would be much more valuable than my speculation. To some degree, it may have been so different that some of those who came from the coax/RF world and didn't have much experience with IP networks might have seen it as a bit of a threat to their job security, and didn't want it to succeed. But maybe calling it an "IP mess" was justified, perhaps it was just a poorly designed product, or wasn't very reliable. I have no idea.

My guess is the biggest problem with the concept of the MFH3 was that the single headend was such a low volume product they weren't able to reduce the cost and increase its potential market. It was a chicken and egg problem. Because it was so expensive, only very large MDUs could consider it (amortizing the cost over many subscribers) Because it had such a small potential market, the volume could never support the cost of redesigns of the product to take advantage of technology improvements that would normally drive down the cost of a product over time.

I'm not sure exactly what format the data from the headend to the receiver was, but it was obviously at a point "somewhere" in the tuning process between a raw signal and HDMI output. The H20 didn't have ethernet, so that had to be added, and changes made to allow passing data from the ethernet port to the tuner (to finish whatever remained of the process of turning the signal into HDMI output) Since they couldn't be used as normal receivers, they didn't add bits to the existing tuner, but replace it entirely, making the receivers also a relatively low volume product.

It shouldn't have been all that difficult a proposition to update receivers beyond the H20i & HR20i. They already had ethernet, they just needed a bridge between the network and tuner, though that depends on what exactly was being passed over the wire. At any rate, by the time they had the opportunity to add it to the design of a future receiver so all receivers would be compatible with the MFH3, they probably realized it the head end was never going to drop in cost due to the very low volumes and they were already planning on letting MFH3 die.

Perhaps they were starting to move in the direction of the DSWM by this point, and knew that would be a better and far less expensive way to provide similar capability. Even if one single DSWM can't serve a large building by itself like a MFH3 headend could, you can use however many DSWMs you need - all located in the same place - connect them all to a switch, and feed it into the building network, or possibly a dedicated network. Need more capacity, add one more DSWM for another 100 (or whatever) tuners. The only place you need to deal with RF is distributing the LNBs to all the DSWMs, past that point you're freed from the limitations of RF.


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## peds48 (Jan 11, 2008)

slice1900 said:


> I'm not sure exactly what format the data from the headend to the receiver was, but it was obviously at a point "somewhere" in the tuning process between a raw signal and HDMI output. The H20 didn't have ethernet, so that had to be added, and changes made to allow passing data from the ethernet port to the tuner (to finish whatever remained of the process of turning the signal into HDMI output) Since they couldn't be used as normal receivers, they didn't add bits to the existing tuner, but replace it entirely, making the receivers also a relatively low volume product.


IIRC, there was never an H20i, just an HR20i, and a D11i


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Perhaps they were starting to move in the direction of the DSWM by this point, and knew that would be a better and far less expensive way to provide similar capability. Even if one single DSWM can't serve a large building by itself like a MFH3 headend could, you can use however many DSWMs you need - all located in the same place - connect them all to a switch, and feed it into the building network, or possibly a dedicated network. Need more capacity, add one more DSWM for another 100 (or whatever) tuners. The only place you need to deal with RF is distributing the LNBs to all the DSWMs, past that point you're freed from the limitations of RF.


Something most of your line of reasoning seems to miss is DirecTV tries to keep legacy support as much as they can.
The move to SWiM & connected home, did cause the loss of older receivers.
The MFH3 systems weren't compatible with anything else.
When you're in the business of feeding your product through "RF", you're well versed at how to deal with "limitations".
DirecTV has put a lot of effort into a "one coax solution" and I expect they'll continue, and shy away from their venture into an IP based system.
I know it's hard for "network folks" to realize it isn't the best solution for everything.


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## veryoldschool (Dec 10, 2006)

peds48 said:


> IIRC, there was never an H20i, just an HR20i, and a D11i


By those models, it looks like MFH3 was a backup in case SWiM didn't work out.
Once SWiM proved its worth, that was the end of any MFH3 development.


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## slice1900 (Feb 14, 2013)

peds48 said:


> IIRC, there was never an H20i, just an HR20i, and a D11i


There was an H20i, I've seen them on Ebay.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Something most of your line of reasoning seems to miss is DirecTV tries to keep legacy support as much as they can.
> The move to SWiM & connected home, did cause the loss of older receivers.
> The MFH3 systems weren't compatible with anything else.
> When you're in the business of feeding your product through "RF", you're well versed at how to deal with "limitations".
> ...


They also want to move toward simpler/cheaper installs, and there's no way RF distribution can compete with IP for price in an MDU. RF requires too much hardware, and even the cabling itself is more expensive. In the home the price difference would be a wash, and they wouldn't want to deal with a homeowner's possibly broken network (i.e. same reason installers must use DECA for a supported whole home install, even though ethernet is better than DECA across the board)

I could see them requiring a separate network for a supported MDU install, so the MDU can keep full control over the infrastructure it uses, but it would still be cheaper than installing it using the Sonora/MFH2 model.

Obviously IP would only make sense for a brand new MDU install, if you've already got all that equipment in there, you'd never want to rip it out and replace with an IP solution, you'd just expand as necessary using similar technology to what's already there.

I think for an IP solution to be workable they'd have to enable all receivers after a certain point to support it, not some special 'i' models like before. Like I said, I think there's a chance Genie, as the most recent receiver, might already have this capability, or is at least closer to what would be needed as evidenced by the DECA bridge. They could build an H26 and HR26 and ship them for an IP MDU, similar to how they will only deliver D12s if a SWM account adds an SD receiver.

Residential accounts would still be using any SWM compatible receiver, so they wouldn't be rendering anything obsolete, just restricting what can be used where, which is already true in the distinction of what you're shipped depending on whether you have SWM or not.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> They also want to move toward simpler/cheaper installs, and there's no way RF distribution can compete with IP for price in an MDU.


 
Maybe it's a question of scale, but to go MFH3/IP you have to move everything to the head end.
This might makes sense if you're serving 500 units.
MFH2 is much more flexible for scale.
I wouldn't use Sonora for pricing.
Moving to something like a DSWM version of the SWM-32 with "say" 90 channels, would reduce/simplify what's needed "in the closet" to supply the units.
Have you ever lived somewhere that didn't have coax, but did cat5?

I don't think it makes sense to have receivers that would be "RF & IP". For cost, it would be either or.


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## JosephB (Nov 14, 2005)

veryoldschool said:


> I don't think it makes sense to have receivers that would be "RF & IP". For cost, it would be either or.


I don't know that this makes sense. All the boxes are capable of IP for VOD, etc. It doesn't seem too extraordinarily difficult or expensive to develop box to be able to direct streams from the ethernet port to the decoding hardware instead of the RF tuner.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Maybe it's a question of scale, but to go MFH3/IP you have to move everything to the head end.
> This might makes sense if you're serving 500 units.
> MFH2 is much more flexible for scale.
> I wouldn't use Sonora for pricing.
> ...


You make it sound like moving everything to the head end is a bad thing. I think that is a good thing, because all the RF infrastructure is in that one spot (plus the dish, which is hopefully just a floor or two up if you had your choice of where to put the head end)

MFH3 wasn't a problem because everything was in the head end, it was a problem because the head end cost a fortune, and you'd have to buy it up front before you could serve your first customer. Using IP DSWMs would also allow moving everything to the head end, but wouldn't cost a fortune. Unlike an MFH3, capacity could be added as needed by adding DSWMs, instead of paying for all the capacity necessary for the entire building up front.

I agree that there aren't likely to be any buildings built for some time that don't have coax run to multiple rooms in each unit, just as there wouldn't likely be any built that don't have cat5e/6a run in a similar manner (probably to the same wall plates) My argument is that given the ability to use either option in a new building that has both, it would make more sense to use DSWMs with IP output in a single head end, rather than distribute the trunk lines and use a DSWM with SWM output on every floor MFH2 style.

We already have receivers that are capable of both IP and RF, so I don't think there is any extra cost required at this point. MRV/RVU receives a stream from a DVR over whatever path it is configured to use for IP - whether it be DECA, ethernet, or now wireless. That's not I/Q data, of course, for that we'd need a path into the tuner at the point where it turns I/Q data into MPEG data, just like RVU was provided a path at the point where it turns MPEG data into HDMI data. The progression of technology in Directv's receivers has been for more flexibility, as the Genie's ability to bridge IP and DECA shows - in order to do that, it had to provide a path into and out of the part of the tuner that decodes DECA. As I said, I wouldn't be surprised if the Genie has the hardware (if not the software) designed as necessary to receive I/Q data over IP and turn it into a picture. If it doesn't, it merely requires adding another "path" similar to what has already been done.


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## inkahauts (Nov 13, 2006)

I'm going to throw out some guesses:

The DSWM13 is going to be short lived much like the SWM5 was.

We'll see a DSWM13 LNB.

We'll see a DSWM with around 20 or more for MDUs.

The SWM-32 could be replaced with a DSWM with around 90.

Output power will increase to support 400' runs.


I like your guesses.

My only question is what about those houses now that have a swim 14 to 32 tuners. I guess use the mdu 20 tuner version so they have less stuff over all to manufacture at that point?


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## inkahauts (Nov 13, 2006)

Maybe I'm confused but I've still not seen one thing that explains to me why IP is at all better than a rf Dswim system in a house or a mdu. It'd have to stay isolated and since most places run one cat and one coax they'd have to install a second cat line everywhere or use deca. Plus there's usually not cat in a central place in a building. Just a central closet for each individual unit where the coax comes in from cable and or sat. To which then I say whats the point? And are you saying you don't need switches to split cat to every unit just like you'd need splitters sticking with good old rf? 

And a new development isn't going to want to run cat and coax from a building closet to a unit. And your not going to get anyone. To build from the ground up for just dtv. That will never happen either.


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## veryoldschool (Dec 10, 2006)

JosephB said:


> I don't know that this makes sense. All the boxes are capable of IP for VOD, etc. It doesn't seem too extraordinarily difficult or expensive to develop box to be able to direct streams from the ethernet port to the decoding hardware instead of the RF tuner.


If it's a IP system, why pay for the SAT tuner chip?
If they already can handle IP, why are the MHF3 folks "Stuck with" the HR-20i only?


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## veryoldschool (Dec 10, 2006)

inkahauts said:


> I like your guesses.
> 
> My only question is what about those houses now that have a swim 14 to 32 tuners. I guess use the mdu 20 tuner version so they have less stuff over all to manufacture at that point?


Figuring the DSWM13 LNB covers "most homes" and when it doesn't the DSWM xx "stand alone" is used like the SWiM-16 is today.

Twin DSWM xx would cover the "few" 32 tuner homes.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> You make it sound like moving everything to the head end is a bad thing. I think that is a good thing, because all the RF infrastructure is in that one spot (plus the dish, which is hopefully just a floor or two up if you had your choice of where to put the head end)


The cost for the massive tuner banks is the "bad thing".

You haven't "sold me" that the 3rd version of the DSWM isn't going to need some sort of tuner and decoder to get to streaming over IP.
After all, no matter how small you make the filter, it still needs to be demodulated.

I think your missing what RVU is. It's already been decoded, by either coming off the hard drive or on it's way to the drive.


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## inkahauts (Nov 13, 2006)

I'll go for that.

And if it's IP based then wouldn't they have to move all the tuners to the Dswim? Not just be able to split the signal by tuner but decoding and encrypting too? 

I whish we had more details on how exactly the ip system worked. What did it split and what did it send where? I was under the impression it simply turned a swim channel into an ip based channel of a transponder for distribution only. The idea of a fully ip based system now would need to be very different to be worthwhile IMHO than that concept if that's how it worked.


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## JosephB (Nov 14, 2005)

veryoldschool said:


> If it's a IP system, why pay for the SAT tuner chip?
> If they already can handle IP, why are the MHF3 folks "Stuck with" the HR-20i only?


Why pay for the SAT tuner chip? To reduce the number of SKUs they have to support. If they can redirect the bits coming in from the ethernet port to the decoding/decryption hardware without any additional hardware--ie: do it all in software--then why not? Then you can just use whatever boxes the installer has on the truck, you have in the warehouse, or that you have in development. Of course we have no real knowledge of the architecture of the hardware or software in a modern SWM and MPEG-4 capable receiver, but it's not a stretch to imagine they could enable that functionality in software.

And, as far as MFH3 capability, it all depends on what the IP stream of MFH3 vs. DSWM looks like. It may be that the MFH3 does something to the stream, changes the format, demuxes it, something, that means they have to cut ties with it and start all over with the DSWM.


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## veryoldschool (Dec 10, 2006)

JosephB said:


> Why pay for the SAT tuner chip? To reduce the number of SKUs they have to support. If they can redirect the bits coming in from the ethernet port to the decoding/decryption hardware without any additional hardware--ie: do it all in software--then why not? Then you can just use whatever boxes the installer has on the truck, you have in the warehouse, or that you have in development. *Of course we have no real knowledge of* the architecture of the hardware or software in a modern SWM and MPEG-4 capable receiver, but it's not a stretch to imagine they could enable that functionality in software.
> 
> And, as far as MFH3 capability, it all depends on what the IP stream of MFH3 vs. DSWM looks like. It may be that the MFH3 does something to the stream, changes the format, demuxes it, something, that means they have to cut ties with it and start all over with the DSWM.


"And I don't either", so I'll go with: if it was that easy, they would have already done it.
They could push the new software as part of the installation and the customers would have HR24s [or maybe a Genie] instead of an HR20i.
There was a rumor of a HR24i, but nothing came of it.

The DSWM is using digital filtering so each channel is narrower and they can double the number of channels. Its output is still analog RF.

Slice has looked at patents "and dreamed" what they might do, but not every patent sees the light of day.
By the time "a box" is converting the SAT feed to IP, it no longer is a SWM as we know them, be it analog or digital.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> Maybe I'm confused but I've still not seen one thing that explains to me why IP is at all better than a rf Dswim system in a house or a mdu. It'd have to stay isolated and since most places run one cat and one coax they'd have to install a second cat line everywhere or use deca. Plus there's usually not cat in a central place in a building. Just a central closet for each individual unit where the coax comes in from cable and or sat. To which then I say whats the point? And are you saying you don't need switches to split cat to every unit just like you'd need splitters sticking with good old rf?
> 
> And a new development isn't going to want to run cat and coax from a building closet to a unit. And your not going to get anyone. To build from the ground up for just dtv. That will never happen either.


There is a limited amount of the DSWM's network that needs to be isolated on a separate network, or subject to QoS.

There's no reason you can't use the existing wall ports in the units. You do not need to have dedicated "Directv only" jacks or dedicated edge switches, as you seem to be implying. Ethernet switches isolate traffic port to port, and support line speed bidirectionally from many ports simultaneously. It is almost impossible to overwhelm even the bargain switches you buy at Walmart - it would take a concerted effort with full bandwidth traffic at a majority of the ports, implying cooperation in this amongst multiple units (and protecting against people deliberately being jerks is almost impossible, you might as well also worry about what happens if someone injects high powered RF noise into the coax in their unit, or for that matter connects the center conductor to a 110v outlet)

At most you need one simple rule before commencing troubleshooting - receivers must be plugged directly into the wall port, not into a switch connected to that wall port. Once the feed from the DSWMs (whether via private network or enforced by QoS) reaches the edge switch, it is shared with all the other traffic, and that will not present any problem for real world use.

Not to mention, by the time an IP based DSWM was actually a reality, there will be almost no difference in the per port cost of 10Gb ethernet ports, so a new buildout at that time will provide 10Gb to every wall port. A Genie's 5 tuners would consume at best a mere 1% of that.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> If it's a IP system, why pay for the SAT tuner chip?
> If they already can handle IP, why are the MHF3 folks "Stuck with" the HR-20i only?


That is in fact what is discussed in the DSWM patents, and even in the original SWM patents. They've been wanting to eliminate the tuners for a long time, but they would need some transition time where receivers could be capable of living in both worlds. Similar to how they built receivers capable of both legacy and SWM operation for several years before they left legacy operation behind and produced SWM only receivers.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> The cost for the massive tuner banks is the "bad thing".
> 
> You haven't "sold me" that the 3rd version of the DSWM isn't going to need some sort of tuner and decoder to get to streaming over IP.
> After all, no matter how small you make the filter, it still needs to be demodulated.
> ...


I wasn't suggesting that what the IP DSWM would output is the same thing RVU is. The DSWM would output I/Q, so the tuning job is only partly done.

I was merely comparing to the two in that both have IP data that is being handed over into what used to be a wholly RF task. You used to have the input from the RF port and the output HDMI (or whatever) video. RVU tosses IP data in near the end of that process. An IP DSWM would toss IP data in a bit earlier in that process. The tuner has one point where it begins to process the I/Q data passed down to it from an earlier stage of the tuner. It would merely need a second pathway at that point to have I/Q data passed to it via the IP interface. It would not be a complicated change at all.

Though as you say in a previous post, there would be savings to be had by eliminating that earlier part of the tuner that would no longer be necessary in receivers that only work with an IP DSWM. And like SWM only receivers, those would probably appear eventually.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> I'll go for that.
> 
> And if it's IP based then wouldn't they have to move all the tuners to the Dswim? Not just be able to split the signal by tuner but decoding and encrypting too?
> 
> I whish we had more details on how exactly the ip system worked. What did it split and what did it send where? I was under the impression it simply turned a swim channel into an ip based channel of a transponder for distribution only. The idea of a fully ip based system now would need to be very different to be worthwhile IMHO than that concept if that's how it worked.


Well, the DSWM outputting IP I'm talking about is a very specific creature that is mentioned in the DSWM patent as the third embodiment of the invention. Several possible forms it might take are shown - which tells me that unlike the first two embodiments, it didn't really exist even on the drawing board at the time the patent was written (and as VOS says, may never exist)

The third gen DSWM the patent discusses outputs I/Q in its IP incarnation (the SWM incarnation pastes together the individual channels into invented "transponders" and converts back to analog to distribute SWM channels via RF) The channel is separated from the transponder, but is only sort of half tuned. This is what would be passed around via IP, it would need to be demodulated, decrypted, and then the MPEG stream decoded before it could be displayed. So the receiver wouldn't be entirely out of work, but a good chunk of the tuner's job would be taken away from it.

In principle, there's no reason the DSWM couldn't demodulate the I/Q and pass out encrypted MPEG, and they could always implement it that way at some point. All the original SWM patents actually specify as one option a SWM that contains a full tuner per channel, allowing it to output channelized encrypted MPEG. I suppose cost, as well as heat/power kept that idea from being realized back then and we got one of the other options, the SWM we know today.


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## P Smith (Jul 25, 2002)

> The DSWM would output I/Q


It wouldn't happen as I already gave a reason
again, it's very sensitive _short_ lines and guarded from EMI inside of a tuner's can; the current trend is make one chip with a tuner and demod chip, hence no I/Q bus exposed


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## HoTat2 (Nov 16, 2005)

P Smith said:


> It wouldn't happen as I already gave a reason
> again, it's very sensitive _short_ lines and guarded from EMI inside of a tuner's can; the current trend is make one chip with a tuner and demod chip, hence no I/Q bus exposed


Possibly true;

But then again, I don't really understand what the advantages of taking the satellite stream all the way down to the baseband I/Q signals in the DSWiM are to begin with as suggested in the third embodiment.

To me it seems ultimately performing frequency and time de-multiplexing of the transponder stat-mux stream in a DSWiM unit to produce just the single data packet stream of an individual program channel carried on a transponder should be a sufficient goal for the final third embodiment.

To try and go further than that is probably too ambitions and unnecessarily complicating the design of the DSWiM negating whatever potential gains there would be of going down to the BB I/Q signals.

The packet stream of a single programming channel would be a very narrow-band transmission and more efficient as opposed to sending the entire transponder multiplex to an IRD only to have it dispose of almost all the data packets except the ones pertaining to the channel it seeks.

This will permit the use of many more SWiM channel carriers for RF distribution or provide low data rate ethernet streams for wire or even wireless IP distribution schemes to the IRDs.


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## slice1900 (Feb 14, 2013)

P Smith said:


> It wouldn't happen as I already gave a reason
> again, it's very sensitive _short_ lines and guarded from EMI inside of a tuner's can; the current trend is make one chip with a tuner and demod chip, hence no I/Q bus exposed


The DSWM would be converting from IF to I/Q wholly in the digital domain. 'Sensitive short lines' and EMI are not relevant.


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## P Smith (Jul 25, 2002)

those lines are not exactly digital (take a look at constellation of 8PSK signal), I/Q is all about precise phase shift between I and Q, adding to that new DVB-S2 xxAPSK modulation will require fine levels too, not just a phase
nay, there is something different in DSWIM ...

also about packets - you can't apply to I/Q; that TS or part of it (set of particular PIDs) is coming out of DEMOD chip, what is feeding by these I/Q lines (often by pair with differential signals to eliminate EMI to the signals)


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> The DSWM would be converting from IF to I/Q wholly in the digital domain.


This is where you change from the frequency domain to a time domain, right?
You're no longer using a Single Wire aka SWM without time sharing.
RF does "one thing well": streaming.


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## AntAltMike (Nov 21, 2004)

I'm late coming to this thread, as I just yesterday got my notice of the DRE Loop- through training seminars, and I haven't had time to wade through all 150+ posts here, but I'll comment for now on a few of the earlier ones.

The impetus behind increasing the number of tuners that can be supported by a single SWM line is that most older hotels use vertical "loop" wiring, which starts at the top of a column of rooms and on each floor, has a valve that is either a "tap" or a "directional coupler" that bleeds a small amount of signal off for use at that wallplate and passes the remainder along to service the wallplates on floors below. While this wiring is nearly always shielded RG-6, and while the taps or couplers can be inexpensively replaced with ones that are rated for L-band frequencies, there are still two obstacles to using that wiring for SWM-based, DRE installations. One is that as far as I know, up until now, DirecTV had not been approving loop wiring distribution for DRE systems, 2) I have never seen a directional coupler that was explicitly rated to carry the 2.3 MHz return signals that SWM uses, and 3) many, if not most, vertical wiring in hotels has more than 8 taps on it. In my primary market, Washington, DC, where we have more uniform building height restrictions than do most large cities, maybe 80% of the downtown hotels are ten stories tall, so a SWM riser wire that starts at room 1001 runs out of assignable transponders at room 301. Increasing the number of tuners supportable on one single coax to 13 will bring scores of hotels in my market into play for DRE system upgrades.

Until recently, DirecTV and DISH have had little competition from franchised cable for hotel guest room business, but that is changing rapidly. The cable company can deliver digital standard definition pictures with no headend cost to cable card equipped or Pro Idiom equipped TVs and that blows away analog standard definition and there is no hardware per-channel cost to increasing the size of those programming packages, so DirecTV is either going to have to make its DRE system more practical for loop wired buildings or risk losing those accounts to cable. That makes it worth their while to push this SWM13 out the door pronto, even if it is not in its final form, but it just doesn't seem all that valuable to the residential viewer, as any residential needs can readily be met by running one SWM line for each eight tuners. Putting more than 8 on one coax is a convenience, but also a luxury for residential applications


I have also read a few of the posts regarding "IP" based distribution, but since I have only read about one quarter of this thread, what I am about to say might already have been said and of so, I'm sure that someone will so inform me. 


1) In hospitality guest rooms, the guest needs to be able to control his selection of programming with his television's remote control. Can that be done with an IP based system?

2) It has been the policy of DirecTV and DISH that the signal must be securely encrypted to the set. Do these so-called IP based alternatives meet this requirement?

3) What kind of cabling will be needed to support IP-based distribution? To send HDMI over Cat 5 wiring with the common adaptors I have seen and used fully utilized two Cat 5 wires. Is there some more efficient wiring usage that can carry this television data load and still be simultaneously used for other purposes?


Two other matters I saw near the beginning of this thread:

1) Regarding ATSC licensing, I think that it is the 8VSB modulation that is still under patent, but I would expect any distribution system that tries to utilize a modern TV's digital tuner would use QAM.

2) Back in Post #26, slice1900 said that he thought that the SWM13 design didn't use SAW (surface acoustic wave) filters, but also that it seemed to be doing what the SWM 8 did, which was to pluck and frequency-shift the IF transponders. I don't see how that can be done without SAW filters. 
A decade ago, 1RU modulators with SAW filters cost twice as much as modulators without them, but since then, the price of modulators that use them has plummeted, to where I think all commercial television channel modulators now use SAW filters and I buy the whole mini-mods new, retail, in single quantities for $70 each. I'd be surprised if the SAW filter in those units cost someone more than a couple of dollars, if that, but regardless of that guess, if a SWM 16 has 16 of them in it and if a SWM13 has 13, I just don't see the cost of them being all that important because anyone in the commercial distribution business can readily afford a SAW filtered SWM port per TV drop now.


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## P Smith (Jul 25, 2002)

instead of SAW new DSWIM will use FFT and CPU power to cut/shift chunks of spectrum


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> This is where you change from the frequency domain to a time domain, right?
> You're no longer using a Single Wire aka SWM without time sharing.
> RF does "one thing well": streaming.


The translation between frequency domain and time domain would be accomplished via a Fourier transform, which the DSWM patent shows as one of the stages. It also shows polyphase filters and Hilbert transforms being employed. I don't claim to understand exactly how this all works, even though I sort of understand the mathematics I don't know anywhere near enough about RF to begin to comprehend the process. The patent doesn't go into much detail, since this process is not the subject of the patent. It is treated as a 'solved problem'.

As I've mentioned before, the third embodiment, unlike the first two, does not read like something that was even on the drawing board at the time the patent was written. Hence the three options shown for what it does with the I/Q it produces (SWM output in two 500 MHz wide channels, demodulated IP output that I believe would be RVU compatible, and some middle option that the text suggests is I/Q over IP, but the drawing shows something a bit different)

I don't really understand your comment about 'time sharing' and SWM, can you elaborate?


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## inkahauts (Nov 13, 2006)

Slice. Here's what I still don't get on ip based in a condo. You are talking about taking a ip system into an central closet in each unit and plugging it into their router and using their system for distribution. That means every unit will have to require its own router and network switches as needed through the building. You really think DIRECTV would ever even consider using peoples own routers and such to rely on for distribution? Forget the fact I don't understand how you think your going to keep everyone isolated in the first place from each other but we all know that while switches may work fine you are bringing in routers to the mix with this plan and that's asking for trouble. And I am sure it'd cost more for DIRECTV to build and use a specific router for everyone's home. And just like they did with deca they don't want to be in charge of trouble shooting a customers home network. They would have to if they are using it for their stuff, or for their distribution. Customer has a massive ip conflict issue with stuff other than dtv that's messing with the router. Kills dtv. That won't go over well at all. And That's a massive amount of training for an installer.

Hotels might be easier with two distinct networks and limited on what it does. But Why build two ways of doing something if you can build one way that works everywhere and with anything? IP doesn't meet those goals from what I can see. And I don't see it being cheaper. Of anything more expensive in the long run when everything is taken into consideration. 

Sometimes new tech isn't better than old tech for certain things. 

I can see then wanting a Dswim that will tune a channel instead of a transponder which would be much more Channels per Dswim unit and probably lnbs able to do 30 tuners or more for home market which could reduce costs big time, and say 50+ channels for hotels condos etc. But, still in the rf world not ip. I just haven't seen where it's a benefit in all you have said.


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## slice1900 (Feb 14, 2013)

AntAltMike said:


> 1) In hospitality guest rooms, the guest needs to be able to control his selection of programming with his television's remote control. Can that be done with an IP based system?
> 
> 2) It has been the policy of DirecTV and DISH that the signal must be securely encrypted to the set. Do these so-called IP based alternatives meet this requirement?
> 
> ...


1) I'm not sure what you're asking here. In a SWM system the remote has to tell a receiver located somewhere to change its channel, which notifies the SWM8 (or whatever) it is attached to via the 2.3 MHz back channel. If the DSWM output IP but still used a receiver, it would work the same way except the back channel happens via IP. If there is no receiver involved (i.e. RVU over IP to a RVU compatible TV) then the remote would tell the TV, which would make the request for a new channel via IP.

2) There is no mention of encryption in the patents. Directv would probably use the same scheme they use where the access cards have to perform the decryption. Or if RVU type streams were being passed, it would be done in the same way it is done today for RVU compatible devices.

3) IP distribution wouldn't send HDMI, it would send MPEG streams or I/Q that when demodulated result in MPEG, so the bit rate per channel would be in the 10-20 Mb/sec range for HD channels, allowing for plenty of channels even over inexpensive gigabit ethernet, which can be run on ordinary cat5 cable.

The reason I mentioned ATSC and licensing costs in the past is that there is no particular reason why a DSWM couldn't be built which included an OTA port, and could distribute OTA channels over SWM channels. If the DSWM did the demodulation and fed the channels via RVU, the only ATSC/8VSB licensing costs would be for the DSWM, not for all the attached devices. The patent does not mention this _at all_, so I don't want anyone to think this is anything other than my crazy idea!

Regarding the SAW filters, the DSWM does A/D conversion from baseband IF (that is, it takes the satellite IF frequencies, which have been shifted down to baseband frequencies to make for easier Nyquist sampling) It performs operations on digital data, eliminating the need for SAW filters. The intro to a paper about the DSWM's ASIC presented at a conference earlier this year specifically mentions cost saving from eliminating SAW filters being one of the primary goals behind the DSWM's design.

The SWM8 has 9 SAWs, the SWM16 18 (gotta remember that guide channel ) The DSWM13 has no SAW filters.

BTW, thanks the explanation about why the DSWM13 is valuable for hotels. I saw what someone posted about that before where it mentioned "pass through capability" but I wasn't sure what that meant. Now it makes perfect sense!


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## slice1900 (Feb 14, 2013)

inkahauts said:


> Slice. Here's what I still don't get on ip based in a condo. You are talking about taking a ip system into an central closet in each unit and plugging it into their router and using their system for distribution. That means every unit will have to require its own router and network switches as needed through the building. You really think DIRECTV would ever even consider using peoples own routers and such to rely on for distribution? Forget the fact I don't understand how you think your going to keep everyone isolated in the first place from each other but we all know that while switches may work fine you are bringing in routers to the mix with this plan and that's asking for trouble. And I am sure it'd cost more for DIRECTV to build and use a specific router for everyone's home. And just like they did with deca they don't want to be in charge of trouble shooting a customers home network. They would have to if they are using it for their stuff, or for their distribution. Customer has a massive ip conflict issue with stuff other than dtv that's messing with the router. Kills dtv. That won't go over well at all. And That's a massive amount of training for an installer.
> 
> Hotels might be easier with two distinct networks and limited on what it does. But Why build two ways of doing something if you can build one way that works everywhere and with anything? IP doesn't meet those goals from what I can see. And I don't see it being cheaper. Of anything more expensive in the long run when everything is taken into consideration.
> 
> ...


Regardless of how the receivers get their IPs (i.e. whether the DSWM assigns them via DHCP or they are assigned in some other manner and the DSWM is told what the IP addresses of the receivers are) you'd use a separate "Directv" VLAN anywhere the network is shared. IP conflicts could avoided by having the arp table in the DSWM only speak to the MAC/IP combo it has already learned, or this can be enforced in some managed switches.

There isn't any requirement for a router, just because you want to use a DSWM on the building network. The building itself doesn't have to have a router (except where it connects to the internet) though most buildings of any size will - and once you a certain size you must, as there is a limit as to how large a flat switched network can become. Certainly there is no requirement for a router per unit, I have no idea where you're getting that idea. The units may have a wireless router plugged in somewhere (though you hope the building provides wireless so every unit doesn't have a wireless router all stepping on each other) but the receivers would not be able to plug into that, they'd have to plug directly into a wall port, which would be configured on the switch at installation time to be on the Directv VLAN.

If you unplugged the receiver and plugged something else in, it wouldn't work (if arp security is enabled) and certainly couldn't reach the internet, so a port would be either configured to be useful for Directv, or useful for accessing the internet/rest of the building network, not both. You could plug in a small switch if you wanted multiple receivers served from the same location, though depending on how things are configured you might need to get the MDU to do something on their end, rather than being able to simply decide to do it on your own.

In buildings with a core router, the DSWM(s) would connect to one port of that router, which would have QoS configured to insure Directv got sufficient bandwidth. Alternatively, if you wanted to use a private network and bypass the core router, the DSWM(s) could be connected to a switch which is connected to every edge switch, with the ingress port of each configured for the Directv VLAN. You get full bandwidth port to port from there to anywhere else. The only way you see problems if you don't have QoS on that switch is if somehow the bandwidth of the entire switch fabric is exceeded. Even if you were cheap and used unmanaged switches at the edge which don't support QoS, exceeding the capacity of the switch fabric one of those mostly theoretical problems, which can only happen if someone really goes out of their way to make it happen.

It all comes down to how this is marketed. If people in the traditional MDU market are installing it, they're going to want to use coax because it is job security. If you have have an IP install, basically you need someone who knows Directv stuff to install the dish and DSWM, but if they made a friendly GUI front end for managing it, your network guy can do it. There's little role for a Multiband (or whatever that MDU company everyone hates is called) at that point.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I don't really understand your comment about 'time sharing' and SWM, can you elaborate?


RF can have more than one "stream" one the wire, due to being in the frequency domain.
Fiber shares this with different wavelengths of lasers.
"IP" or cat5 only has one path in either direction. To have more than one stream, they need to time share as there is only "one frequency".

BTW

I've heard "my guesses" could be off by "a lot".
The DSWM may only end up in a very limited application and may not go any farther.

It nice to think of "what could be", but only time will tell "what will be".


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> It all comes down to how this is marketed. If people in the traditional MDU market are installing it, they're going to want to use coax because it is job security. If you have have an IP install, basically you need someone who knows Directv stuff to install the dish and DSWM, but if they made a friendly GUI front end for managing it, your network guy can do it. There's little role for a Multiband (or whatever that MDU company everyone hates is called) at that point.


If you check into the DirecTV MHF3, you'll see that is exactly what they promote.
The system is monitored by a 3rd party "for a fee".


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## inkahauts (Nov 13, 2006)

Regardless of how the receivers get their IPs (i.e. whether the DSWM assigns them via DHCP or they are assigned in some other manner and the DSWM is told what the IP addresses of the receivers are) you'd use a separate "Directv" VLAN anywhere the network is shared. IP conflicts could avoided by having the arp table in the DSWM only speak to the MAC/IP combo it has already learned, or this can be enforced in some managed switches.

There isn't any requirement for a router, just because you want to use a DSWM on the building network. The building itself doesn't have to have a router (except where it connects to the internet) though most buildings of any size will - and once you a certain size you must, as there is a limit as to how large a flat switched network can become. Certainly there is no requirement for a router per unit, I have no idea where you're getting that idea. The units may have a wireless router plugged in somewhere (though you hope the building provides wireless so every unit doesn't have a wireless router all stepping on each other) but the receivers would not be able to plug into that, they'd have to plug directly into a wall port, which would be configured on the switch at installation time to be on the Directv VLAN.

If you unplugged the receiver and plugged something else in, it wouldn't work (if arp security is enabled) and certainly couldn't reach the internet, so a port would be either configured to be useful for Directv, or useful for accessing the internet/rest of the building network, not both. You could plug in a small switch if you wanted multiple receivers served from the same location, though depending on how things are configured you might need to get the MDU to do something on their end, rather than being able to simply decide to do it on your own.

In buildings with a core router, the DSWM(s) would connect to one port of that router, which would have QoS configured to insure Directv got sufficient bandwidth. Alternatively, if you wanted to use a private network and bypass the core router, the DSWM(s) could be connected to a switch which is connected to every edge switch, with the ingress port of each configured for the Directv VLAN. You get full bandwidth port to port from there to anywhere else. The only way you see problems if you don't have QoS on that switch is if somehow the bandwidth of the entire switch fabric is exceeded. Even if you were cheap and used unmanaged switches at the edge which don't support QoS, exceeding the capacity of the switch fabric one of those mostly theoretical problems, which can only happen if someone really goes out of their way to make it happen.

It all comes down to how this is marketed. If people in the traditional MDU market are installing it, they're going to want to use coax because it is job security. If you have have an IP install, basically you need someone who knows Directv stuff to install the dish and DSWM, but if they made a friendly GUI front end for managing it, your network guy can do it. There's little role for a Multiband (or whatever that MDU company everyone hates is called) at that point.


In a condo.....

Homeowner has a router or his inter access...

Cat cable to behind the tvs is plugged into said router do DVD player etc. 

You will be sharing that with the DIRECTV ip cat based system. 

Yes? 

You are not running a second cat line. Therefore the dtv cat lines must go through that persons router....

Yes?

Most if not all people will have Internet and a router. Heck DIRECTV wants everyone connect to the Internet. 

Yes?


Trying to spell it out in simplest form because I think your going over my specific concern.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> RF can have more than one "stream" one the wire, due to being in the frequency domain.
> Fiber shares this with different wavelengths of lasers.
> "IP" or cat5 only has one path in either direction. To have more than one stream, they need to time share as there is only "one frequency".
> 
> ...


OK, I understand what you're getting at. IP is all or nothing in this regard. Either the link has sufficient bandwidth to carry the data, or it doesn't. When you stream over the internet it "streams ahead" so you can tolerate brief interruptions. An IP DSWM would work in a similar manner, so there wouldn't be any hard real time requirements. Perhaps if you had a SWM attached and IP attached receiver operating in parallel you might see the IP receiver operating ever so slightly behind due to this.

It would be disappointing if the DSWM has only limited application and doesn't go any further. But it wouldn't be completely shocking, considering that the original SWM patents included ideas such as including tuners and modulators inside the SWM, which were obviously never implemented. As you've said, just because there are patents, doesn't mean the device will become a product. Still, the patent did read as though the first two embodiments had already been built, or close to it. It does seem like a perfect fit for a DSWM LNB to supply enough tuners for almost all residential situations, but if they don't do it they'll have their reasons, even if we never know them.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> In a condo.....
> 
> Homeowner has a router or his inter access...
> 
> ...


Ah OK, you're talking about buildings where the cat5 in the wall ports connects to back somewhere _inside that unit_. I'm talking about buildings where the cat5 is connected outside the unit, i.e. to a shared wiring closet serving the entire floor.

In a condo like you describe IP delivery would not be an option.

The buildings I'm describing would wire to a shared wiring closet because that's required if they want to provide internet to all the residents as part of the deal. That's how most newer buildings in the medium/large size range would be wired. Those older than 10 years or so, or on the smaller end would wire within the unit like you're saying, and everyone would have to separately subscribe to cable or DSL for internet.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I've heard "my guesses" could be off by "a lot".
> The DSWM may only end up in a very limited application and may not go any farther.
> 
> It nice to think of "what could be", but only time will tell "what will be".


Thinking about it further, no matter what they very likely would need to replace the current SWMs, and would 100% for certain have to replace the SWM LNBs, to be able to handle the new RDBS and Ka from 101 capability they're already licensed for and are launching satellites next year to make happen.

They will have no choice but to change from 4 to 6 coax from a legacy dish to a SWM, there is simply no way they can add 4x500 MHz and 4x400 MHz IF bands to the existing 4 coax stack plan, even if they go up in frequency, unless they went above 3 GHz. The only way current SWM8 and SWM16 would work for this is if the two flex ports are far more flexible than we know - able to handle the full range of IF frequencies from 250 MHz to 2150 MHz. Furthermore, the SWM would either need to handle > 2150 MHz frequencies or be able to substitute Ka/RDBS 36 MHz wide transponders for the 110/119 Ku band 24 MHz wide transponders in the 950-1450 MHz range on the 22 KHz tone cables. The original SWM patents had a paragraph discussing use of 88 KHz signaling, they would need to support something like that to be able to select the 5th and 6th LNBs, or use some sort of baseband signals similar to the 2.3 MHz SWM FSK.

If they replace the SWM8 and SWM16 with new models that are otherwise the same except they add support for all this, well, let's just say I'd be very surprised and wonder what the issue was with the DSWM that made them stick with the old analog technology and the expensive SAW filters.... I'm guessing you probably have access to some pretty good insider info as far as what you "heard", but I just don't see any way that when they introduce the new LNB that the SWM version of it uses the old technology instead of DSWM. We'd have to conclude DSWM was an utter failure if that were to happen.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Thinking about it further....


I'm not sure what's going to happen with RDBS, and you've echoed a point I brought up some time back: What's the IF going to be????
I saw one of your LNB diagrams and it looked "a bit out there" to be something DirecTV would do, so I'm guessing there is another plan.
The "potential" of the first gen DSWM is there and I think it's sound.
I'm waiting to hear more "soon" :lol:

Our thoughts in this thread may just be sooner than we'll see anything, but unless something else comes along, it would seem that "someday" we'll see more of the DSWM as it's simply a more efficient way to use the bandwidth and have more channels.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I'm not sure what's going to happen with RDBS, and you've echoed a point I brought up some time back: What's the IF going to be????
> I saw one of your LNB diagrams and it looked "a bit out there" to be something DirecTV would do, so I'm guessing there is another plan.
> The "potential" of the first gen DSWM is there and I think it's sound.
> I'm waiting to hear more "soon" :lol:
> ...


I agree, we'll probably run out of speculations long before we actually learn any new facts about the DSWM, especially models beyond the DSWM13.

I assume the diagram you thought was "out there" was the one where I tried to crowd everything into the current frequency range using 50 MHz guard bands, as an alternative to your scenario of using higher frequency ranges for RDBS? That was before I even realized they were also licensed for Ka from 101, so that one is clearly DOA. There is just no way they can do it with a four coax stack.

I have a pet theory on "what I'd like to see" from a six coax stack plan, because it appeals to my sense of order, though I suspect Directv doesn't take elegance of design into consideration, but has rather more practical concerns! :lol:


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I assume the diagram you thought was "out there" was the one where I tried to crowd everything into the current frequency range using 50 MHz guard bands, as an alternative to your scenario of using higher frequency ranges for RDBS? That was before I even realized they were also licensed for Ka from 101, so that one is clearly DOA. There is just no way they can do it with a four coax stack.


It was the one where there were two positions of LNBs and a reflector/window added.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> It was the one where there were two positions of LNBs and a reflector/window added.


That drawing was from a Directv patent, to support simultaneous reception of both Ka and Ku from the 101 orbital. I found more about the material being used. It is thin layer of dielectric sandwiched between metal with specific patterns carved into it, covered/protected by plastic. Obviously some type of metamaterial. Ku reflection costs 0.7 db, Ka transparency costs only 0.04 db.

If they chose not to use that solution, then I guess they must widen the dish's focal point to reflect to four feedhorns in the 99 - 103 range, instead of three. I assume you pay for widening the focus by reducing your gain. If they did that, would the loss of gain affect all three orbitals, or just 101? Let's say you located the Ku feedhorn above the Ka feedhorn, I wonder if the dish's geometry could be engineered so there is no difference in gain from 99 & 103 whether or not reflection into both the Ka and Ku feedhorns from 101 was occurring? More importantly, how would this solution compare in overall efficiency for 99, 103 and 101 versus a dish designed per the patent using the metamaterial, since it has almost no Ka loss (and the modest Ku loss would not be an issue)

The patent claimed that Ka from 99 and 103 would see additional gain resulting from replacing the center Ku feedhorn with the smaller Ka feedhorn, because some "compromises" in geometry had to be made with the Ku feedhorn there. It also shows that the Ka feedhorns for 99 & 103 need to be made slightly larger to support RDBS, making correcting that geometry compromise even more important. I'm sure none of us would mind more gain on the HD sats.

Based on that, it seems like a slam dunk to replace the 101 Ku feedhorn with Ka, the questions are where does the 101 Ku feedhorn go, how to you reflect signal to it, and how much gain does it cost for 101 Ku, 101 Ka and 99/103 Ka versus the alternatives?


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## veryoldschool (Dec 10, 2006)

The material [performance] seems reasonable as there is significant difference in frequencies.
Some concerns I have about using it as shown:
The new placement of the Ku 101 LNB will have less beam focus.
Rain & snow [collection] would seem to have more impact.

Multi LNB dishes are a mix of compromises, so it's hard to say what would be the best arrangement.

If they drop the 110 & 119, could they "double stack" the LNBs and change the reflector shape to support enough signal for the two? :shrug:

Here's an "off the wall" question:

If they use this material in a feedhorn, could it support both Ku & Ka by picking out the Ku before the Ka?


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> The material [performance] seems reasonable as there is significant difference in frequencies.
> Some concerns I have about using it as shown:
> The new placement of the Ku 101 LNB will have less beam focus.
> Rain & snow [collection] would seem to have more impact.
> ...


You might be right about snow collection, with the Ku feedhorn low on the arm and so near the dish. I had wondered about how the little reflector on the arm would be affected by hail and bird poop, but knowing more about what it is made of I'm no longer concerned about that.

Why do you think the Ku feedhorn would get less beam focus in that spot? Isn't the focus a function of the focal length - i.e. on the distance from the dish to the feedhorn? There should be an optimal placement for the reflector and feedhorn that maintains the identical distance. Do you think there would be focus issues no matter where they're located? Unless the effect is large, I'm not convinced I should care about a small drop in signal quality for 101 Ku. That's the highest signal quality sat we have now, and the one that suffers least from weather. It has more margin to "burn" than the rest, as far as I'm concerned.

I fully expect them to drop 110 and 119 in the new LNB. There is so much capacity going online with D14 and D15 alone that the small number of transponders on 119 could be replicated somewhere on the new sats. The transponder map spreadsheet shows 7 active CONUS transponders from 119. These are 24 MHz wide Ku transponders. This would fit onto about 4 1/2 36 MHz wide RDBS transponders. Perhaps fewer, if 119 is using a less efficient modulation scheme and/or all 7 transponders are not fully utilized. If only the D12 receiver had been designed for MPEG4, they could halve the number of transponders needed for this exercise. Down the road, they could do this for the 9 transponders on 95. Then every new install could use one dish and one LNB (well, two, SL4 and SL4S)

I have no idea whether the metamaterial could be used in a feedhorn or not, but that is an interesting idea. I'd have to know something about a feedhorn actually works to be able to make any useful comments on your idea  That brings up another possibility that might make this a drop-in replacement for a Slimline LNB, without needing to replace the arm, as well as minimizing your snow collection and beam focus concerns. If you had this material sitting at a 45* down angle just in front of the 101 Ka feedhorn (but sized to reflect the full width required for the Ku feedhorn) you'd have the Ka feedhorn as normal and the Ku feedhorn at a 90* vertical angle in relation to the rest of the feedhorns. I don't know if the through loss for Ka is impacted by passing through at a 45* angle, but considering how tiny the loss is head on, even if it's higher at an angle it's likely to still be minimal.

In the D14 thread, DianaC wondered if you couldn't make an entire second dish out of this material, sitting just short of the Ka-reflecting dish, so that the Ku focal point could be at a different location than the Ka focal point. I have no idea how costly the material is to make, but probably isn't too bad since the materials used aren't exotic. If that was manageable the only downside would be some increase in the weight of the dish.


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## veryoldschool (Dec 10, 2006)

Reflecting off a flat surface means you've lost any further focal length.

You might not have the same "pass through" if you're at 45 degrees as "I'd imagine" the openings that pass Ka will be reduced.

I don't know if the material could be used in a combo feed horn, "but" at "first pass" [of the idea] it would seem to work.
Feed horns start large and step down.
Placing the material after the Ku pickup would give this pickup a ground plane, while passing the Ka to its pickup through the smaller stepped part of the feed horn.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> *Reflecting off a flat surface means you've lost any further focal length.*
> 
> You might not have the same "pass through" if you're at 45 degrees as "I'd imagine" the openings that pass Ka will be reduced.


I thought the principal being applied for the Ku feedhorn in the patent was the same as used in folded optics. Where a "plane" or "flat" secondary reflector actually does extend the "overall" focal length to that of the Ka feedhorn using a direct path as in the illustration?








Extending this to the RF domain in the patent, the Ka feedhorn would be positioned at the "X" position on the left in the image and the Ku feedhorn to the vertex point marked by the asterisk-like symbol on the right side (ignoring the illustration of chromatic aberration in the slightly different focal points here),

The plane reflector would be transparent to Ka signals of course and reflective of Ku ones.


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## veryoldschool (Dec 10, 2006)

"I'm not sure" as RF isn't exactly the same as light and tends to spread more.
You're diagram looks to use a convex secondary to extend the focal distance beyond the primary while "defusing" the focal "point".

If it was flat & didn't effect the focal distance, wouldn't it look like:


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## inkahauts (Nov 13, 2006)

slice1900 said:


> Ah OK, you're talking about buildings where the cat5 in the wall ports connects to back somewhere _inside that unit_. I'm talking about buildings where the cat5 is connected outside the unit, i.e. to a shared wiring closet serving the entire floor.
> 
> In a condo like you describe IP delivery would not be an option.
> 
> The buildings I'm describing would wire to a shared wiring closet because that's required if they want to provide internet to all the residents as part of the deal. That's how most newer buildings in the medium/large size range would be wired. Those older than 10 years or so, or on the smaller end would wire within the unit like you're saying, and everyone would have to separately subscribe to cable or DSL for internet.


Well, that is how they are building buildings today, so its what you have to look at, and I don't see that changing, every new development in southern California is set up that way. I haven't seen one home or condo or apartment designed the way you are suggesting. Not one. Where have you? They have a building closet where all possible sources come into, and then the appropriate ones are split and sent to the individual units, which each have their own central distribution system in the specific unit. Usually they run twoe coax and one Ethernet for phone, and have a conduit to pull more cables through if its needed from the building closet to the unit closet.

Therefore, if that wont work in this kind of system, there's no point in this kind of system for consumers, and again, I don't see them making separate systems if they can make one that works for both...And that would be cheaper.. And keep their stuff not at all confusing to peopel who might otherwise try and plug in their dvd player cat cables to the dtv cat jacks, so to speak...


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> "I'm not sure" as RF isn't exactly the same as light and tends to spread more.
> You're diagram looks to use a convex secondary to extend the focal distance beyond the primary while "defusing" the focal "point".
> 
> If it was flat & didn't effect the focal distance, wouldn't it look like:
> ...


FWIW, the patent states:



> Further, although FSS *404* is typically contemplated as a flat surface, FSS *404* can be a curved surface, or any shaped surface which allows for placement of feedhorns *114*B across a larger arc and/or further out of the path of signals *106*A and *402*. Further, FSS *404* can be used to focus the signals incident on feedhorns *114*B if desired.


If the surface is curved, would that allay your concerns regarding loss of Ku beam focus?


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> If the surface is curved, would that allay your concerns regarding loss of Ku beam focus?


It wouldn't take much of a curve.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> Well, that is how they are building buildings today, so its what you have to look at, and I don't see that changing, every new development in southern California is set up that way. I haven't seen one home or condo or apartment designed the way you are suggesting. Not one. Where have you? They have a building closet where all possible sources come into, and then the appropriate ones are split and sent to the individual units, which each have their own central distribution system in the specific unit. Usually they run twoe coax and one Ethernet for phone, and have a conduit to pull more cables through if its needed from the building closet to the unit closet.
> 
> Therefore, if that wont work in this kind of system, there's no point in this kind of system for consumers, and again, I don't see them making separate systems if they can make one that works for both...And that would be cheaper.. And keep their stuff not at all confusing to peopel who might otherwise try and plug in their dvd player cat cables to the dtv cat jacks, so to speak...


What you're describing there sounds like the cat5 entering the individual units isn't live? Or is it being used for a telephone in some units? Assuming you have one unused cat5 or better (all 4 pairs) run to each unit from a central point in the building or on each floor of the building, this could be made to work. The MDU would manage/hardcode IP addresses into the DSWM, and all receivers. The DSWM would be connected to a switch that is in turn connected to all those unused cat5s going to every unit (all one switch or one switch with other switches connected to it, doesn't matter) No routing required. All these switches would be managed switches, to allow broadcast filtering and port based ARP mapping to prevent broadcast storms and IP conflicts. Pretty basic stuff any enterprise quality managed switch can do.

It wouldn't really matter what equipment was in the units, so long as the outside line and all Directv receivers were interconnected via gigabit ports. Give the residents a choice: We'll install and support your Directv and provide you with a little switch that will be connected to the outside line and the wall ports serving your receivers. If you mess around with what we've setup, that's fine, but if it stops working and you call us, the first thing we're going to do is to put everything back and if that makes it work then obviously you broke it - so we'll charge a $100 "no trouble found" fee for wasting our time.

No matter what the resident does to the setup, as long as the path from outside line to receiver is connected by switches or the switch ports of a wireless router, it'll work. Switches don't care about subnets or IP addresses, they pass traffic based on MAC address. The resident could of course mess up their own Directv reception if they don't know what they're doing or have some internal network problems, but the protections on the managed router avoid allowing them to mess up the Directv in other units.

Sounds great, right? So what's the downside? No internet access from the receivers. The MDU could provide that, and would have to provide enough bandwidth to cover residents accessing PPV over the internet. If they're willing to do so, great. If not, then the receivers would need to access the resident's network for that. This could be accomplished by replacing the switch the MDU provides with a basic router, that would perform the same function but also have a port that connects to the resident's network and obtains an IP address via DHCP, which all the receivers would be routed through when they need to hit the internet.


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## HoTat2 (Nov 16, 2005)

peds48 said:


> It is for DRE and D2
> 
> Click for large view - Uploaded with Skitch


Since the second scheduled DSWiM-13 seminar is now near or probably completed by now, sure hope an attendee will chime in here with what they've learned about it.


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## AntAltMike (Nov 21, 2004)

I missed yesterday's session at West Chester Pennsylvania yesterday, because I had mistakenly thought it was today, but then they sent out notification of a couple more sessions, one local to me in two weeks that I expect to be attending.

HD Headend Technologies December 4, 2013 West Chester, PA 9:00 AM - 4:30 PM 
DRE Plus Loop Through December 5, 2013 West Chester, PA 9:00 AM - 4:30 PM 
HD Headend Technologies December 11, 2013 Las Vegas, NV 9:00 AM - 4:30 PM 
DRE Plus Loop Through December 12, 2013 Las Vegas, NV 9:00 AM - 4:30 PM
* All times listed local times for the city that the class is held.


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## HoTat2 (Nov 16, 2005)

OK;

I see these seminars don't specifically mention the DSWiM-13 as one of the "features" to be discussed for the meetings on DRE systems (the COM 1000 systems wouldn't use them of course), but perhaps it will be anyhow.

Look forward to your report back here on it if it is ...


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> OK;
> 
> I see these seminars don't specifically mention the DSWiM-13 as one of the "features" to be discussed for the meetings on DRE systems (the COM 1000 systems wouldn't use them of course), but perhaps it will be anyhow.
> 
> Look forward to your report back here on it if it is ...


When the cover letter says "burn before reading... " I'm not sure how much will get posted here.
I will "confirm" a lot of this thread is on the right track.


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## Sixto (Nov 18, 2005)

Interesting.


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## veryoldschool (Dec 10, 2006)

Sixto said:


> Interesting.


Jan 15th we'll know more


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## inkahauts (Nov 13, 2006)

Now I am intrigued as to which of the tons of things that have been said are on target, and do any of them in any way maybe coincide with the bss sats going up....


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## veryoldschool (Dec 10, 2006)

yes :lol:


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## slice1900 (Feb 14, 2013)

Ask a general question, get a general answer! :lol:


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## inkahauts (Nov 13, 2006)

:lol:


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## slice1900 (Feb 14, 2013)

Since it isn't clear what the BSS/RDBS sats will be doing as far as providing customer content, all we can go on is the statement in the preface to the DSWM paper that one of the goals behind its design was flexibility for "many more satellites". At the time I wrote some of the stuff here I under the mistaken impression that Directv would be adding Ka from 101 for customer content at some point, not realizing it was already used internally (though it still isn't clear exactly where it fits within the delivery system for LiL) That would have most definitely required a new LNB, but since that Ka from 101 is not being added for customer use I'm back to considering the possibility that since nothing much is changing beyond the possibility of adding BSS from one or two locations, perhaps the existing LNBs were designed for that from the start.

Due to the way it works, the DSWM should be pretty future proof toward future changes/additions to what the LNB provides. Whether it turns out it is a necessary upgrade to access whatever customer content there may be from the BSS satellites is another matter. If the LNB was built able to handle BSS, the analog SWMs would definitely have been built to do so as well, and the first generation DSWM will turn out to be pretty uninteresting outside of the narrow market at which it has been mentioned as being intended for.

I keep kicking myself for throwing out my bad LNB earlier this year. I wanted to take it apart and have peek inside but one of the screws was stripped (or maybe it was some sort of security screw?) so I tossed it. Should have saved it until I could borrow a sawzall for a minute. A peek inside may allow identification of the DROs. Whether there are two or three of them would quickly answer the question of whether it can receive BSS or not.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Since it isn't clear what the BSS/RDBS sats will be doing as far as providing customer content, all we can go on is....


I've seen some "fingerprints/cookie crumbs" pointing to using the two flexports for Ka hi/low, which would suggest a new LNB with 6 outputs.
WorldDirect would need a new diplexer to combine its Ku.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> I've seen some "fingerprints/cookie crumbs" pointing to using the two flexports for *Ka hi/low*, which would suggest a new LNB with 6 outputs.
> WorldDirect would need a new diplexer to combine its Ku.


Don't you mean use the two flexports for the down-converted RDBS R/LHCP IF signals?

If true, wow ... , now 6 lines needed from the LNB to the multiswitch?

Definitely only practical for outdoor mounting of the SWiM switch then.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I've seen some "fingerprints/cookie crumbs" pointing to using the two flexports for Ka hi/low, which would suggest a new LNB with 6 outputs.
> WorldDirect would need a new diplexer to combine its Ku.


I'd been wondering if the flex ports on the SWM8/16 were capable of making use of the Ka IF bands of 250-750 and 1650-2150 MHz. Are these cookie crumbs anything you can share? I imagine not, or you probably would have  I kind of guessed that since the flex ports used the same Ku IF range from 950 - 1450 Mhz as the other 4 LNBs, it "might make sense" to extend that to doing the same with the Ka IF range, but lacked a way to find out.

One of the reasons I'd been off on the idea of 6 LNB cables before was Sonora's recent introduction of a brand new amplifier that included two flex ports, while keeping the current frequency ceiling of 2150 MHz. I found that interesting, since the second flex port hadn't been used for years now and there was nothing on the horizon to suggest Directv was going to add any more single use sats like the 95* and former 72.5*. One can understand keeping the unused flex port "just in case they bring it back someday" even if they didn't know any future plans Directv had for it, but similar reasoning would have them also increasing the amplifier's rated frequency range above 2150 MHz "just in case"...

Using the two flex ports is one way for D14/D15 to serve BSS/RDBS, without messing with the current frequency range, and maintaining the existing investment in SWMs (and for me to be happy I have two spare coax from my old 72.5* dish that could be used for this)

As for 95, using a diplexer as you suggest would work and reduce loss over the other alternative of using a splitter/combiner. The problem is that unless you've identified which cables are which from inside to the roof, you won't know which ones are connected to the flex ports, and you must use those. I'm still of the opinion that if BSS from 99 & 103 will be used for customer broadcast, it makes a lot of sense to use a half dozen of those new transponders to replicate the content from 119 and 95 and have a single 3LNB dish for all installs (well two, the SWM and non-SWM version) But strangely Directv didn't ask for my opinion so there's no reason to believe they'll take my advice 

I wonder how the signalling to the two additional coax would work? My money's on proprietary DiseqC commands to identify to the LNB which cables are connected to the two flex ports. If you look at Sonora's polarity locker, the version shown on their site now has graphics on the front of it suggesting it supplies 20v (i.e. 18v) to both flex ports. Older versions showed graphics on the front indicating they were capable of supplying either 20v or 14v, presumably switched via DiseqC. Sonora's new amp also lists "18v" on both flex ports. So it appears something may have changed in Sonora's understanding of the voltage requirements for the flex ports, and there's only one possible source for that information.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> Don't you mean use the two flexports for the down-converted RDBS R/LHCP IF signals?
> 
> If true, wow ... , now 6 lines needed from the LNB to the multiswitch?
> 
> Definitely only practical for outdoor mounting of the SWiM switch then.


If by the time this new LNB is needed they can provide a second generation DSWM, with 20+ SWM channels on a single output in a DSWM LNB, you pretty much solve that problem for 99.9% of residential installs. Even the current 13 channel DSWM would probably cover 98% of them. Commercial installs will need to add one or two coax if they don't already have six available, no way around it.

I wonder what MDU installers have been trained to do in the last few years since 72.5* went away? Sonora's newer drawings all show the standard four LNB polarities plus a 95* dish. Were installers trained to add a "spare" coax, or somehow subtly pushed towards running 6 coaxes even when a 95* dish wasn't being used? If they have been, that would be a pretty big indication that this is where we're headed.


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> Don't you mean use the two flexports for the down-converted RDBS R/LHCP IF signals?
> 
> If true, wow ... , now 6 lines needed from the LNB to the multiswitch?
> 
> Definitely only practical for outdoor mounting of the SWiM switch then.


Yes, these are the IFs


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> If by the time this new LNB is needed they can provide a second generation DSWM, with 20+ SWM channels on a single output in a DSWM LNB....


While I won't say "never", there are *no signs* of anything more than 13 on a single output.

BTW they haven't asked me either on how "I'd have done it". :icon_cool


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## Stuart Sweet (Jun 19, 2006)

I think the 6th output on the amplifier (which I'm guessing is the DIRECTV TAMP_6) could be used for running cable modem service.

Sent from my iPad using Tapatalk


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> ... I wonder how the signalling to the two additional coax would work? My money's on proprietary DiseqC commands to identify to the LNB which cables are connected to the two flex ports. If you look at Sonora's polarity locker, the version shown on their site now has graphics on the front of it suggesting it supplies 20v (i.e. 18v) to both flex ports. Older versions showed graphics on the front indicating they were capable of supplying either 20v or 14v, presumably switched via DiseqC. Sonora's new amp also lists "18v" on both flex ports. So it appears something may have changed in Sonora's understanding of the voltage requirements for the flex ports, and there's only one possible source for that information.


My guess would be that if re-tasking the flexports is indeed to be the method for adding the RDBS band into the mix for the external SWiM switch case anyhow, is that the SWiM 8/16's two flexports will be polarity locked at the nominal 13 and 18 volts at their outputs to signal to the new LNBF for the R/LHCP 9 channel RDBS transponder sets respectively.

And while in the past there was never been a need for the 13v control voltage from the flexports, I can't believe they can only produce the 18v nom. voltage implied by the newer Sonora illustrations and not be able to provide the 13 volt if called upon. Otherwise why still call them "flexports" which is a contraction of the expression "flexible ports." 

Granted the flexports may not be able to generate 13 or 18 volt signals with the 22 KHz tone, (or can they?) but should be able to at least produce a 13 or 18 volt signal at their outputs if needed.

I also agree that if the World Direct dish is needed it would have to be diplexed in, which means the converted RDBS IF range cannot use the traditional 950-1450 MHz L band. At least not on the coax carrying the IF for the RDBS' LHCP signals which is where the WD dish would need to be diplexed to, and which the installer will have to take great care to correctly identify before diplexing into.


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## Stuart Sweet (Jun 19, 2006)

My guess is that RDBS has nothing whatsoever to do with this device.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> While I won't say "never", there are *no signs* of anything more than 13 on a single output.
> 
> BTW they haven't asked me either on how "I'd have done it". :icon_cool


It wouldn't make sense to release the DSWM13 if the second generation product was coming out right on its heels. But if they wait until after D15 launches and is in position and fully tested (assuming it does go to 103) before doing anything with BSS, we're into early 2015 before they really need new LNBs. I don't know how far in advance of me knowing about it you might see "signs". On the other hand, if a third generation DSWM would be possible shortly after when they'd be able to do a second generation, they'd skip the second generation entirely. Its all guesswork.

There's no particular reason why they couldn't have offered SWM LNBs with multiple outputs, I suppose they didn't because it is really no different than mounting a SWM16 at the dish. Maybe they'll do with the same with a DSWM26 at the dish, or maybe there would be a DSWM26 LNB with two outputs. Either way, they don't want to tell people who have four coax running inside their house already that they need to run two more, or installers might look like this: :blackeye:


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## Stuart Sweet (Jun 19, 2006)

It seems to me that you are thinking of this product as something it probably isn't. I can't imagine it's a replacement for any current SWM product.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> My guess would be that if re-tasking the flexports is indeed to be the method for adding the RDBS band into the mix for the external SWiM switch case anyhow, is that the SWiM 8/16's two flexports will be polarity locked at the nominal 13 and 18 volts at their outputs to signal to the new LNBF for the R/LHCP 9 channel RDBS transponder sets respectively.
> 
> And while in the past there was never been a need for the 13v control voltage from the flexports, I can't believe they can only produce the 18v nom. voltage implied by the newer Sonora illustrations and not be able to provide the 13 volt if called upon. Otherwise why still call them "flexports" which is a contraction of the expression "flexible ports."
> 
> ...


How would the LNB distinguish between the flex ports and the regular 18v and 13v no tone ports if they do it like you suggest? Currently they use the voltage and tone to tell the LNB to output each of the four specific stacked outputs. They would need to be able to tell the LNB to produce the 5th and 6th stacked outputs.

Simply using 18v and 13v no tone would leave no way for the LNB to tell which is which, unless you say "hey, we've already abandoned legacy capability in our latest receivers, so we'll just have 6 specific outputs on the new LNB" (i.e. no longer integrate a multiswitch into the LNB) Installers would need to identify which cable is which for installs using SWM8/16, and new multiswitches would have 6 unmarked inputs and it wouldn't matter what you put where.

I suppose that's possible, but seems more likely they'd keep doing things the way they are now. That means either the two flex ports would need to use DiseqC commands to switch to those 5th and 6th outputs, or you'd need a different way of signaling. The original SWM patents described a 88 KHz tone the receiver would send out to tell if it is attached via SWM or not during "initial setup". AFAIK that isn't used, though receivers DO seem to be able to tell whether they're attached via SWM or not when you do a satellite setup, so maybe it is used?


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> It seems to me that you are thinking of this product as something it probably isn't. I can't imagine it's a replacement for any current SWM product.


I realize the DSWM13 product right now is targeted at a pretty narrow market for hotels, but that doesn't mean it, or future versions of DSWM technology, won't be used for a wider market later. It was designed to cost less and be more flexible than the existing SWM technology - thus entirely replacing it at some point. You probably know what a DSWM13 costs and it may be priced more like a SWM32 than a SWM8 at the moment, but that's the stated intention behind the design of the DSWM technology, even if it might not quite be there yet and even if Directv currently is not using/supporting its use in residential installs at this time nor has any announced intention to do so.

We're sort of running with VOS' mention of "fingerprints and cookie crumbs" regarding use of the flexports for Ka. Unless D15 is going to some other location to provide Ka and everyone has missed the approval, or they're going to stop using Ka from 101 for internal use and use it for customer content, this trail of cookie crumbs would seem to be leading to RDBS from 99 and/or 103 connected to the flex ports at the Ka IF frequencies.

If you run with that and assume a 6 output LNB, then you're left with the problem of how to manage that for residential installs since a lot of people are already unhappy about 4 coaxial cables coming inside their house, and would probably like 6 even less.

It could all be a wild goose chase, but its an entertaining way to kill a few minutse a Saturday afternoon waiting for the SEC and B1G championship games later today


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> I think the 6th output on the amplifier (which I'm guessing is the DIRECTV TAMP_6) could be used for running cable modem service.
> 
> Sent from my iPad using Tapatalk


The problem with that theory is that not only are the 5th and 6th outputs marked "flex 1" and "flex 2" (which doesn't necessarily mean anything) it's rated range is 250 - 2150 MHz, well above the bottom of cable/OTA frequencies. It might work for cable/OTA amplification if it amplifies below 250 MHz, but the product doesn't appear to be designed or spec'ed for such use.

Sonora's LA product range seems to be what you use if you want to amplify cable or OTA signals, none of the inputs/outputs are marked for any particular use and the rated range is 54 - 2150 MHz forward, and passes 2 to 40 MHz reverse with a bit of loss, so it would work fine for cable/OTA. With a 2 MHz bottom, it would even pass SWM (without DECA) in a pinch, I suppose.


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## Stuart Sweet (Jun 19, 2006)

That seems like quite a theory you've concocted for yourself, based on four words from VOS.

And I would not worry too much about using Sonora amps with this switch.


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> How would the LNB distinguish between the flex ports and the regular 18v and 13v no tone ports if they do it like you suggest? Currently they use the voltage and tone to tell the LNB to output each of the four specific stacked outputs. They would need to be able to tell the LNB to produce the 5th and 6th stacked outputs.
> 
> Simply using 18v and 13v no tone would leave no way for the LNB to tell which is which, unless you say "hey, we've already abandoned legacy capability in our latest receivers, so we'll just have 6 specific outputs on the new LNB" (i.e. no longer integrate a multiswitch into the LNB) Installers would need to identify which cable is which for installs using SWM8/16, and new multiswitches would have 6 unmarked inputs and it wouldn't matter what you put where.
> 
> I suppose that's possible, but seems more likely they'd keep doing things the way they are now. That means either the two flex ports would need to use DiseqC commands to switch to those 5th and 6th outputs, or you'd need a different way of signaling. The original SWM patents described a 88 KHz tone the receiver would send out to tell if it is attached via SWM or not during "initial setup". AFAIK that isn't used, though receivers DO seem to be able to tell whether they're attached via SWM or not when you do a satellite setup, so maybe it is used?


Well sure, if the multiswitch is capable of actually producing DiSeqC signaling on the flexports, then yes.

But I wasn't aware the flexports of a multiswitch, be it legacy or SWiM, had this capability. A legacy multiswitch would accept a DiSeqC signal from a receiver or for SWiM a message sent from a receiver over the 2.3 MHz control channel.

Then generate 13 or 18 volts nom. signal voltage on the appropriate flexport output in response, and route the entire transponder set from the LNB to the requesting receiver in legacy installs, Or one of transponder streams within that set for the case of SWiM installations.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> Well sure, if the multiswitch is capable of actually producing DiSeqC signaling on the flexports, then yes.
> 
> But I wasn't aware the flexports of a multiswitch, be it legacy or SWiM, had this capability. A legacy multiswitch would accept a DiSeqC signal from a receiver or for SWiM a message sent from a receiver over the 2.3 MHz control channel.
> 
> Then generate 13 or 18 volts nom. signal voltage on the appropriate flexport output in response, and route the entire transponder set from the LNB to the requesting receiver in legacy installs, Or one of transponder streams within that set for the case of SWiM installations.


You could be right, it depends on what the original design parameters were. If we start with the assumption the flex ports were designed with the ability to pass Ka signals on the SWM8/16, they require a way to identify themselves if they're ever to be used as part of a 6 output LNB (or there is no longer a multiswitch integrated into it, as previously suggested)

If they never contemplated a 6 output LNB, they might still have added Ka capability to the flex ports to give themselves the option of using a separate satellite that provided Ka broadcasts, used similarly to 95W for content of narrow interest, which wouldn't be added to the Slimline LNB.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> That seems like quite a theory you've concocted for yourself, based on four words from VOS.
> 
> And I would not worry too much about using Sonora amps with this switch.


I wasn't suggesting Sonora amps wouldn't work with this switch. The only reason I brought the TAMP-6 up is because it was designed with two flex ports, and maintains the 2150 MHz ceiling. That seems to indicate at minimum that the idea VOS had a while back in the D14 thread that BSS might use frequencies above 2150 MHz is probably not going to happen. The rest is as you say, "quite a theory", but if we all come up with enough theories we're bound to be right with one of them :righton:


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> Well sure, if the multiswitch is capable of actually producing DiSeqC signaling on the flexports, then yes.
> 
> But I wasn't aware the flexports of a multiswitch, be it legacy or SWiM, had this capability. A legacy multiswitch would accept a DiSeqC signal from a receiver or for SWiM a message sent from a receiver over the 2.3 MHz control channel.
> 
> Then generate 13 or 18 volts nom. signal voltage on the appropriate flexport output in response, and route the entire transponder set from the LNB to the requesting receiver in legacy installs, Or one of transponder streams within that set for the case of SWiM installations.


With the old WB68, the flex ports were DiSeqC, and "flexible" as to which port was used for the 72.5 & 95 SATs.
Flex 1 was for 72.5 & flex 2 for 95, but if you only had 95, then it used flex 1.
I don't know if there ever was a reason/need for 13/18 volts, so they may have always been 18 volts since they're DiSeqC.


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## veryoldschool (Dec 10, 2006)

west99999 said:


> Anybody got any info on the new SWM13 switch that is coming out soon?


Here's a pdf
http://forums.solidsignal.com/docs/The%20New%20DRE.pdf

There is a bit more here:
http://forums.solidsignal.com/showth...ial-Experience

Why it's a DSWM13 is because this works with coax networking [DECA] and that is the limiting factor.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> Here's a pdf
> http://forums.solidsignal.com/docs/The%20New%20DRE.pdf
> 
> There is a bit more here:
> ...


Thanks a much for the links! VOS;

Anymore details you know of on the specific carrier frequencies used by the DSWiM-13 as well as a description of its input and output ports?


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## Stuart Sweet (Jun 19, 2006)

That information is confidential at this point but will be revealed when the product actually hits the market (which is expected to be early 2014.)

The key takeaway here is that the DSWM13 is not designed for residential use at this time. It simply doesn't work with residential receivers.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Why it's a DSWM13 is because this works with coax networking [DECA] and that is the limiting factor.


I'm not sure what you mean by "this works with coax networking [DECA] and that is the limiting factor"? Can you explain further?

It looks like the primary difference between this and previous SWMs, other than five more tuners on a SWM output, is that the legacy outputs are stronger, similar to a SWM32, and based on the drawing, supported to cascade at least three levels deep. The SWM output maybe be stronger as well, assuming the "300 feet" thing means 300 feet to the 13th tap.

I wonder what the design target is for the output level at each tap? I guess receivers would need an output of -55 dbm, as IIRC that's what Directv considers the minimum output level they're guaranteed to work at. I think DECA may need more, but since it is lower frequency and experiences less loss through coax and taps designing based on receiver losses should keep DECA within margin.

What I don't understand is why using taps in this manner wouldn't work just as well on a SWM8. Am I missing something? Looking at the entire drawing, everything I see there could be addressed with current equipment as far as I can tell, by adding an amp and four way splitter off each trunk tap since SWM8s can't cascade (or using a single SWM32) and adding SWM amps to compensate for the assumed difference in SWM output strength. The only capability there is no substitute for is having 13 tuners from the SWM output instead of 8, which I imagine is probably the key to making this solution work for this market, otherwise it would have been marketed using SWM8s years ago, since the only missing piece is designing a SWM tap.

Is the difference between 8 and 13 sort of a "magic number" in terms of how hotels are typically wired? That is, is there a best practice that has typically been followed for doing the loop through wiring in hotels that says to not exceed 10 or 12 rooms on a single loop? Obviously if you have a hotel with >8 rooms in a loop a SWM8 is useless, but if you have >13 rooms in a loop the DSWM13 would be as well, so I'm assuming that typically hotels aren't wired with more than 13 rooms per loop?


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## Diana C (Mar 30, 2007)

The "magic" isn't the number of receivers per leg, but the ability to drive each receiver from a tap off a trunk. If you did that at home, you'd have 8 two-way splitters in series. The signal level would drop to unusable levels after the 4th set (and that assumes you stay within current SWM cable length maximums and use RG-6). This switch outputs MUCH higher signal levels (they would probably fry a directly connected receiver) and actually depends on the taps to make sure a safe signal level is delivered to the receiver. The limit of 13 is, most likely, a result of how much power they can push out the port, and how much loss they can tolerate assuming hundreds of feet of RG-59 being used per leg.

The "taps off a trunk line" wiring is just the way hotels are wired. This just makes it practical to use that existing wiring plant for satellite TV.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> That information is confidential at this point but will be revealed when the product actually hits the market (which is expected to be early 2014.)
> 
> The key takeaway here is that the DSWM13 is not designed for residential use at this time. It simply doesn't work with residential receivers.


I would assume that is because hotel receivers can get a firmware update that lets them understand the different SWM output from the DSWM13, i.e. spacing & number of channels. Or are you saying that this requires different receiver hardware, such that hotels that already have receivers must have them all replaced?

I guess I'd be really shocked if the only reason this wouldn't work with residential receivers is that they lack the firmware update the hotel receivers will be getting. If they wanted to start using the DSWM13 for residential installs, they'd all get that firmware update in advance of that.


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## Stuart Sweet (Jun 19, 2006)

Slice1900,

a lot of your questions can't be answered. Not yet. I'm sorry to be firm on that. What I can tell you is that you're off base on a few things. The DSWM13 doesn't have any legacy ports, despite what you see. The output levels you stipulate (presuming you understand that output levels are different over the same distance with different frequencies) are incorrect, and it is simply not possible to use a tap with a residential SWM or SWM32 for many reasons, which I cannot disclose at this point.

Further, although there is such a thing as a SWM amplifier (Sonora's SWMA2 for example), such an amp can't amplify the return path that MoCA needs, so it's useless for any application where MoCA is used (such as MRV or DIRECTV Residential Experience.)

I will say that you are correct in a sense, that the 13-tuner limit and the 300' run are connected in a sense. One dictates the other.


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## slice1900 (Feb 14, 2013)

Diana C said:


> The "magic" isn't the number of receivers per leg, but the ability to drive each receiver from a tap off a trunk. If you did that at home, you'd have 8 two-way splitters in series. The signal level would drop to unusable levels after the 4th set. This switch outputs MUCH higher signal levels (they would probably fry a directly connected receiver) and actually depends on the taps to make sure a safe signal level is delivered to the TV. The limit of 13 is, most likely, a result of how much power they can push out the port, and how much loss they can tolerate assuming hundreds of feet of RG-59 being used per leg.


But what I'm saying is, is there any reason I couldn't obtain some of the taps they're using, and use them on a current SWM? There's nothing magical about a SWM8's output that it can only work with splitters, and not taps. The reason they use taps is because they have much less loss than splitters - the DSWM13 would require much higher output levels than what it has now if it had to drive 12 splitters in series instead of 12 taps in series.


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## Stuart Sweet (Jun 19, 2006)

Yes there is a reason. No I cannot explain further.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> Slice1900,
> 
> a lot of your questions can't be answered. Not yet. I'm sorry to be firm on that. What I can tell you is that you're off base on a few things. The DSWM13 doesn't have any legacy ports, despite what you see. The output levels you stipulate (presuming you understand that output levels are different over the same distance with different frequencies) are incorrect, and it is simply not possible to use a tap with a residential SWM or SWM32 for many reasons, which I cannot disclose at this point.
> 
> ...


Well, I guess I'll be curious to learn why a tap won't work on a current SWM when the time comes, as a tap is merely a splitter with unbalanced outputs 

Using a SWM amplifier at the SWM output wouldn't be a problem, since the return path doesn't need to cross it. All DECA communication occurs on the output side of the amp, between the receivers and the DECA connected home adapter shown in your drawing, and from there to the network switch.


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## Stuart Sweet (Jun 19, 2006)

http://www.shakespeare-online.com/quickquotes/quickquotehamletdreamt.html


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## slice1900 (Feb 14, 2013)

slice1900 said:


> Using a SWM amplifier at the SWM output wouldn't be a problem, since the return path doesn't need to cross it. All DECA communication occurs on the output side of the amp, between the receivers and the DECA connected home adapter shown in your drawing, and from there to the network switch.


Unless the "master control system" in your drawing communicates with the DSWM13s themselves using DECA, for management/monitoring purposes. I guess I wouldn't be at all surprised if that was the cases, since the current SWMs are rather lacking in this department.

If that's the case, then while a SWM amp would work at the output of a SWM8, it wouldn't work at the output of a DSWM13 since DECA would need to pass to the other side of the amp to permit 2 way communication with the DSWM13's "operating system".


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> All DECA communication occurs between the receivers and the DECA connected home adapter shown in your drawing, and from there to the network switch.


"And there's the rub"
There's no need to make more out of this.
The DSWM13 is designed for a target use/application.
300' of RG6 + 13 taps is the max for MoCA.
"End of story"


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## inkahauts (Nov 13, 2006)

slice1900 said:


> I'm not sure what you mean by "this works with coax networking [DECA] and that is the limiting factor"? Can you explain further?
> 
> It looks like the primary difference between this and previous SWMs, other than five more tuners on a SWM output, is that the legacy outputs are stronger, similar to a SWM32, and based on the drawing, supported to cascade at least three levels deep. The SWM output maybe be stronger as well, assuming the "300 feet" thing means 300 feet to the 13th tap.
> 
> ...


He's maybe talking about the fact that deca has a node limit/ distance?

And for the reason 13 is so much more important than 8, look at the doc again. There is specific mention about the networking switch and how many it needs versus an older system... We are talking about a lot of money there too. The dre is evidently very much network driven...

Edit.. Vos beat me to it!


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> What I don't understand is why using taps in this manner wouldn't work just as well on a SWM8. Am I missing something? Looking at the entire drawing, everything I see there could be addressed with current equipment as far as I can tell, by adding an amp, since the only missing piece is designing a SWM tap.


I could make this work, "but" I'd need to have a lot more equipment closets.


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## Diana C (Mar 30, 2007)

slice1900 said:


> But what I'm saying is, is there any reason I couldn't obtain some of the taps they're using, and use them on a current SWM? There's nothing magical about a SWM8's output that it can only work with splitters, and not taps. The reason they use taps is because they have much less loss than splitters - the DSWM13 would require much higher output levels than what it has now if it had to drive 12 splitters in series instead of 12 taps in series.


The problem is that the signal output of a standard SWM is way too low to start with. The taps don't have less loss, they just allocate it differently. A two way splitter outputs 50% of the incoming signal strength to each side of the split. Let's say for the sake of argument that a tap passes 90% down the trunk and 10% to the "tapped" line. To get a signal that is usable to a receiver from a standard SWM would require more amplification than any amplifier can produce. Even if you were able to disable the gain control on a amp such that it did output a hot enough signal, you now run the risk of someone slapping a standard splitter infront of a receiver, or worse, connecting a receiver to the "trunk." Stand back if that happens...you might see the receiver fly across the room in a trail of smoke and embed itself in the wall. 

I doubt you'll ever see this approach used in homes...it just is too risky to be used in an environment were the homeowner is likely to make changes to the wiring.


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## Stuart Sweet (Jun 19, 2006)

That's an excellent point, Diana. You are a very smart person.


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## Diana C (Mar 30, 2007)

I'm just reading what the white paper says...well written piece, IMHO.


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## veryoldschool (Dec 10, 2006)

Diana C said:


> The problem is...


I think you exaggerated to make your point.
A SWM8 outputs -30 dBm, which can be boosted to -20 dBm, which "Oh by the way" is the max input spec for the receiver.

Tap Value 6dB 9dB 12dB 16dB 20dB
MoCA 4 3 2 1.5 1.3 
950MHz 4.5 3.5 2.5 2.1 1.9
2150MHz 4.8 3.8 2.8 2.5 2.3


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## Diana C (Mar 30, 2007)

veryoldschool said:


> I think you exaggerated to make your point....


Indeed, and I hope it was at least a little humorous as well. I just have this mental image of a receiver partially embeded in a wall, with sparks and smoke coming from it.  I know it wouldn't really happen that way. More likely, you'd just turn the receiver into a door stop with no visible effects at all - but where's the fun in that?


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## veryoldschool (Dec 10, 2006)

Diana C said:


> Indeed, and I hope it was at least a little humorous as well. I just have this mental image of a receiver partially embeded in a wall, with sparks and smoke coming from it.  I know it wouldn't really happen that way. More likely, you'd just turn the receiver into a door stop with no visible effects at all - but where's the fun in that?


I sometimes need a 2x4 to get the point across. It's not as humorous, but hopefully lasts awhile.

The DSWM13 will "never" be a DIY install, and "I'd bet" there will be a few AIMs [meters] that will go "poof" before too long too, since they require a 10 dB pad to be used.
"Smoke'em if you gotten'em" !rolling


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## slice1900 (Feb 14, 2013)

inkahauts said:


> He's maybe talking about the fact that deca has a node limit/ distance? And for the reason 13 is so much more important than 8, look at the doc again. There is specific mention about the networking switch and how many it needs versus an older system... We are talking about a lot of money there too. The dre is evidently very much network driven... Edit.. Vos beat me to it!


Nework switches are so cheap, reducing the number of them can't possibly be a motivation. Assuming more expensive managed switches are required to allow the 'master control system' to monitor them, 16 port managed switches from reputable vendors like Cisco and HP cost a couple hundred dollars, you can add additional switches as necessary.

The difference between 13 rooms per switch port and 8 rooms per switch port amounts to a buck or two a room.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Nework switches are so cheap, reducing the number of them can't possibly be a motivation. Assuming more expensive managed switches are required to allow the 'master control system' to monitor them, 16 port managed switches from reputable vendors like Cisco and HP cost a couple hundred dollars, you can add additional switches as necessary.
> 
> The difference between 13 rooms per switch port and 8 rooms per switch port amounts to a buck or two a room.


You're on the wrong track.
It has to do with the MoCA.


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## Stuart Sweet (Jun 19, 2006)

Sorry Slice1900, you're way off here. This system won't work with that $50 switch you buy at Staples and you can't just add more switches, either willy or nilly. This is a very specific installation that's being built here, it's not a whitebox special. Everything about it is proprietary and unique.

Golly jeepers I wish I could be more precise and explain more at this point, I just can't. I will say that your "buck or two a room" estimate is missing a few zeroes. If you'll stipulate to the fact that you can't use SWM8s for loop-through, just trust me on that, the cost to rewire a hotel for home run can get into the six figures on some convention hotels. So using DSWMs with loop through ends up being a ton cheaper even if the multiswitches themselves are more expensive.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> You're on the wrong track.
> It has to do with the MoCA.


OK, you're talking about needing one DECA per 13 rooms rather than one DECA per 8. At list pricing that is a pretty significant savings!


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## Diana C (Mar 30, 2007)

slice1900 said:


> Nework switches are so cheap, reducing the number of them can't possibly be a motivation. Assuming more expensive managed switches are required to allow the 'master control system' to monitor them, 16 port managed switches from reputable vendors like Cisco and HP cost a couple hundred dollars, you can add additional switches as necessary.
> 
> The difference between 13 rooms per switch port and 8 rooms per switch port amounts to a buck or two a room.


I would think it is more like the difference between a port for EVERY room (actually receiver...I'm in a hotel room right now with two HD TVs) and one port per 13 rooms/receivers. In a medium size hotel (300 rooms) that's the difference between 300 ports and 23 ports, or 17 fewer switches. But the real savings is in not needing a Cat 5 run into every room...now you are talking about many thousands of dollars in savings.

Remember...we are putting receivers or DVRs into each room. The guest can make a certain amount of customization of the unit (favorites list, sort order, etc.). The hotel wants to be able to wipe that out without going to every single room (you don't want to try and teach housekeeping to do it). So a network connection is needed for management of the receiver. By using MOCA, the A/V and the management is supported by a single cable (and one that is already in place).


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> OK, you're talking about needing one DECA per 13 rooms rather than one DECA per 8. At list pricing that is a pretty significant savings!


"There's that too"
I think more important though is the amount of "real estate" required for the hardware, and it "would have been" a DSWM15 if the MoCA loss wasn't a problem.


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## Diana C (Mar 30, 2007)

veryoldschool said:


> "There's that too"
> I think more important though is the amount of "real estate" required for the hardware, and it "would have been" a DSWM15 if the MoCA loss wasn't a problem.


Excellent point...you don't want to have to dedicate a guest room to hold all the racks of switches (LAN and satellite).


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## AntAltMike (Nov 21, 2004)

As far as I know, all the current manufacture "taps" I use in multiple dwelling units are DC blocked and the low frequency ratings are commonly 47 MHz, so they may not be suitable for carrying a 2.3 MHz upstream signal. Back in the early 2000s, some manufacturers started labeling their taps as 5 MHz taps, but this industry is notorious for passive product ratings that do not have much integrity. I remember that back when I used to diplex cable TV internet signals with satellite signals in condominiums, I got better performance, which is to say, less loss, on 10 Hz return signals going through Sonora passive products that were rated down to 15 MHz than with other inexpensive products whose labels said they were good to 5 MHz. Those of us who were doing commercial satellite L-band distribution work in the late 1990s may remember that there were lots of splitters bearing labels that said 2,150 MHz where you could peel off that label and the one underneath it said 1,450 MHz. When I fed DirecTV's stacked 2,025 signals through them, they rolled off typically seven or eight dB over that last, or highest 500 MHz.

So if an existing tap label says it is rated to 5 MHz, that wouldn't necessarily make it a brick wall to 2.3 MHz return signals, but it would still pose a practical problem for DirecTV, because they would have no way of ascertaining just how much those dubiously rated 5 MHz taps really rejected 2.3 MHz. My guess for the "how do they do this" sweepstakes is that the return frequency will be higher than 2.3 MHz, and that they utilize the cable TV band to the extent that they may not even have to go to, IIRC, 1890 MHz to stuff 13 dedicated transponders into their plan. Depending on that they can "get away with" for guard bands, they may not even have to go to the L-band.


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## veryoldschool (Dec 10, 2006)

AntAltMike said:


> As far as I know,
> this industry is notorious for passive product ratings that do not have much integrity.


There will be two different part numbers for the taps "before" and "after" the DSWM13, so "SWiM" taps will pass the 2.3 FSK


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## Stuart Sweet (Jun 19, 2006)

No existing taps may be used for this system as specified. There are no currently manufactured taps that are approved for this purpose, and the new ones... the ones that are... are still secret.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> Sorry Slice1900, you're way off here. This system won't work with that $50 switch you buy at Staples and you can't just add more switches, either willy or nilly. This is a very specific installation that's being built here, it's not a whitebox special. Everything about it is proprietary and unique.
> 
> Golly jeepers I wish I could be more precise and explain more at this point, I just can't.


I don't want you to think I'm asking or expecting you to release details you're not allowed to at this time. I've been subject to NDAs or "understandings" about stuff like this many times before.

What you're saying is that everything is sold to customers as a complete package. The fact that pretty much any switch will work (and I can assure you that's the case, ethernet is ethernet) is immaterial because you get what Directv provides you with, and if it breaks you call them for service and it is replaced with the same model or whatever updated model they're using at the time. They may sell a switch 5x more than what it costs if you bought the identical model elsewhere, but you're paying for the support of the product as a whole, not buying parts piecemeal. That's referred to in the IT world as a turnkey system.

I think we're sort of talking around each other here a bit, because I like to talk about technical/theoretical limitations, and you're talking about the product that Directv is selling as a complete package. Whether changing something in even the tiniest way still works or not is irrelevant to you, because there is only one way this system can be sold and supported.

At any rate, we're straying pretty far from the DSWM13 itself that's the subject of this thread, so I'll shut up for now and when you can release more info next year I'll understand the things I'm missing a bit better


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## Stuart Sweet (Jun 19, 2006)

Yeah I'm glad you understand. Of course, yes, I am talking about a turnkey system because for the foreseeable future that is the one and only way this product will be available. I know it seems like we're talking about two different things but since this product will only be part of a turnkey system, I tend to think of the whole system.

I can tell you this, since it applies to current technologies, the process for getting approved for DRE is very comprehensive and DRE system bills of materials are subject to DIRECTV approval. No substitutions allowed. The good news is the hardware really isn't more expensive than comparably configured units; you just pay for the staging and site work.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> "There's that too"
> I think more important though is the amount of "real estate" required for the hardware, and it "would have been" a DSWM15 if the MoCA loss wasn't a problem.


Interesting.

I think I might be circling in on what you're saying. The worst case SWM loss is for the receiver that's furthest from the DSWM13, while the worst case MoCA loss will be to/from the receiver that's closest to the DSWM13, since the DECA adapter is shown at the endpoint of the coax.

I'm sure there's a good reason why the DECA adapter is at the far end rather than next to the DSWM13, and that reason probably has something to do with differences in losses when going in/out a tap port.


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## veryoldschool (Dec 10, 2006)

These are still going to be "big ticket" installs and we won't be seeing "free professional" installation on the work order. :lol:


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Interesting.
> 
> I think I might be circling in on what you're saying. The worst case SWM loss is for the receiver that's furthest from the DSWM13, while the worst case MoCA loss will be to/from the receiver that's closest to the DSWM13, since the DECA adapter is shown at the endpoint of the coax.
> 
> I'm sure there's a good reason why the DECA adapter is at the far end rather than next to the DSWM13, and that reason probably has something to do with differences in losses when going in/out a tap port.


Huh?
The farthest receiver is still the highest loss be it SWiM or DECA.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Huh?
> The farthest receiver is still the highest loss be it SWiM or DECA.


The DSWM13 is at one end of the coax, the DECA adapter is at the other end. If you number the receivers 1 - 13 with one being the closest to the DSWM13 and 13 being the furthest, then receiver 13 has the most SWM loss, but receiver 1 has the most DECA loss.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> The DSWM13 is at one end of the coax, the DECA adapter is at the other end. If you number the receivers 1 - 13 with one being the closest to the DSWM13 and 13 being the furthest, then receiver 13 has the most SWM loss, but receiver 1 has the most DECA loss.


You've got it wrong.
The DECA is with the DSWM13.
If it was at the other end, the directional couplers wouldn't work.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> You've got it wrong.
> The DECA is with the DSWM13.
> If it was at the other end, the directional couplers wouldn't work.


That's not what Stuart's drawing shows. The DSWM13 output is shown going to "13 rooms" and then to a DECA adapter that has its output terminated. If that's not correct, maybe the drawing needs a bit of tweaking to be more clear, as I doubt I'm the only one who reads it like that.

I don't understand your comments about the "directional couplers wouldn't work". You're going to have to go between taps in both directions no matter where the DECA adapter is located. Not only for MoCA, but for SWM as well (i.e. 2.3 MHz return channel)


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## Stuart Sweet (Jun 19, 2006)

The DECA is diplexed in at the beginning of the loop. I'll admit that I didn't know how to show that without putting in a tiny little diplexer and further confusing the drawing. If you have a suggestion, I can always revise the drawing.

Basically the output from the SWM feeds into a diplexer, and the DECA feeds into the diplexer, and the output from the diplexer goes to 13 rooms.

In a DRE system, the receivers report to the server and not to each other.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> The DECA is diplexed in at the beginning of the loop. I'll admit that I didn't know how to show that without putting in a tiny little diplexer and further confusing the drawing. If you have a suggestion, I can always revise the drawing.
> 
> Basically the output from the SWM feeds into a diplexer, and the DECA feeds into the diplexer, and the output from the diplexer goes to 13 rooms.
> 
> In a DRE system, the receivers report to the server and not to each other.


Ah OK. Maybe show two dashed lines exiting the DSWM13, one going to "13 rooms" and the other to the DECA adapter? It would probably be too crowded if you tried to represent the diplexer in there, but at least with two dashed lines it would be clear that DECA isn't at the end point of the coax after the taps/rooms.

I understand that the receivers don't need to talk to each other, but the communication is still bidirectional. i.e. receivers report to server, server commands receivers. So the MoCA crosses tap in/out ports in both directions, and enters the tap port "backwards" when a receiver transmits. I have no idea how the losses for that work out, but maybe that's what VOS was alluding with his comment about how it could have been a DSWM15 if it wasn't for the MoCA loss.


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## Stuart Sweet (Jun 19, 2006)

I think you're on the right track but let's think this out a little further. It isn't two lines out from the SWM. It's something like this diagram, except with different swm's and different diplexers, but the signal flow is similar.

I'm really interested In making that diagram better if you can help.


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## slice1900 (Feb 14, 2013)

I understand that it isn't actually two lines. My thought process is that if you don't have room to show the diplexer dividing the signal between the long coax run and DECA, the next best thing is to show a second dashed line representing that second signal leading to the DECA adapter. That way it is easily understood that the DECA isn't located at the end of the long coax run.

The diagram is still inaccurate that way, and you don't see where that second dashed line comes from, but from my perspective at least I'd say it that change makes it "inaccurate in a less confusing manner" 

But who knows, maybe others think that would make it worse, so if everyone else is happy with it I wouldn't worry about it. There's a good reason why when I do systems design/architecture work I write it into my contract that I be provided with a tech writer to produce these types of documents. Well, the main reason is that I despise Visio because deep down I know all Microsoft products are out to get me, but also because I understand the difficulty of trying to capture a complex design in a single page without making it too busy or require it be printed on a wide format plotter.


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## inkahauts (Nov 13, 2006)

To bad they couldn't build a diplexer input into the dswim13.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> To bad they couldn't build a diplexer input into the dswim13.


For what? I don't think hotels are wanting to diplex in OTA channels.


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## inkahauts (Nov 13, 2006)

For the deca.


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## slice1900 (Feb 14, 2013)

If they were going to do that, then why not build the DECA in?


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I don't understand your comments about the "directional couplers wouldn't work". You're going to have to go between taps in both directions no matter where the DECA adapter is located. Not only for MoCA, but for SWM as well (i.e. 2.3 MHz return channel)


You also don't understand how a directional coupler works.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> You also don't understand how a directional coupler works.
> 
> 
> 
> ...


While not fully grasping the vector illustrations or the distinctions between "incident" verses "forward" power in the diagram VOS.

To simplify, is it basically saying that with a directional coupler signals may pass freely from port A <---> B, or A <---> C, but not B <---> C ?


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> While not fully grasping the vector illustrations or the distinctions between "incident" verses "forward" power in the diagram VOS.
> 
> To simplify, is it basically saying that with a directional coupler signals may pass freely from port A <---> B, or A <---> C, but not B <---> C ?


The "mainline" is thru in either direction. A <-> B
Main to secondary:
A <-> C
B <-> termination


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## AntAltMike (Nov 21, 2004)

HoTat2 said:


> To simplify, is it basically saying that with a directional coupler signals may pass freely from port A <---> B, or A <---> C, but not B <---> C ?


Yes. If you hook up a directional coupler backwards, injecting signal in output port C, the signal measured at tap port B will be down 20dB or more, and not flat across the spectrum, and on the few I've checked, that port loss doesn't seem to vary much with the tap value. Directional couplers are often used in reverse as unbalanced combiners when coupling modulators that have significantly different output levels


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## veryoldschool (Dec 10, 2006)

AntAltMike said:


> Yes. If you hook up a directional coupler backwards, injecting signal in output port C, the signal measured at tap port B will be down 20dB or more, and not flat across the spectrum, and on the few I've checked, that port loss doesn't seem to vary much with the tap value.


That is the directivity of the coupler.
They can have 40+ dB of directivity, but these applications don't need it.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> I think you exaggerated to make your point.
> A SWM8 outputs -30 dBm, which can be boosted to -20 dBm, which "Oh by the way" is the max input spec for the receiver.
> 
> Tap Value 6dB 9dB 12dB 16dB 20dB
> ...


OK;

Just one other clarification needed;

In your post to Diana C you listed these figures.

Are these just the typical level reductions in the mainline signal due to the tap siphoning signal off, i.e. when going from port A to B, of current taps on the market and not any of the ones to be used in the new DSWM13 based DRE system?


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## Stuart Sweet (Jun 19, 2006)

None of those measurements necessarily apply to the DSWM13. Those specs have not been published.

They look like more or less "stock standard" measurements.


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> OK;
> 
> Just one other clarification needed;
> 
> ...


I'd call them generic.
If you want more there are pdfs here: http://sonoradesign.com/1-coax-passives/taps.html


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## AntAltMike (Nov 21, 2004)

I would hope that DirecTV has constructed whatever taps it will be furnishing or approving as "Wall" taps, because the taps that are shaped like two-way splitters often don't fit into existing, single gang electrical boxes. 

There is no technical or even practical barrier to DirecTV incorporating signal amplification above -20dBm in commercial systems, Back in 1998, when Holland Electronics was trying to be the pioneer in loop wire L-band distribution, they sold a beast of an amplifier that had an output level of I think -5dBm to support stacked "Satellite A" signal, and then depicted it going into an eight-way splitter to supply eight riser lines, and then they tapped it off for ten floors of distribution with every tap nominally being between -50dBm and -55 dBm. As someone who has troubleshot similar systems, I have to tell you that the likelihood of the signal on the lower floors being above -55dBm in that scheme was about zero, so I declined to market that system because it would be hell trying to repair a weak riser line when doing so would require occupant-authorized access into all the units the wiring looped through.

Very few MATV riser lines service more than ten floors, though I did have one customer that had 16 floor riser lines of RG-59, but that building was built back when the highest frequency local channel was VHF 13. 

When a building is more than 10 stories tall and they want to use loop wiring, they generally use a split riser scheme, with a two-way splitter at the top of each riser and one splitter output goes directly down to the horizontal midpoint of that riser, to source the lower half.

What kind of relationship does Sonora Design presently have with DirecTV? I remember a decade ago, when DirecTV had cast its lot with NAS (National Antenna Systems), Sonora was kept in the dark and had to react to DirecTV's technology as it was revealed, but now, with DirecTV requiring its approval of DRE systems, there doesn't seem to be a niche for any aftermarket manufacture of parts that is not licensed or otherwise approved.


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## HoTat2 (Nov 16, 2005)

Stuart Sweet said:


> None of those measurements necessarily apply to the DSWM13. Those specs have not been published.
> 
> They look like more or less "stock standard" measurements.


Alright;

Because wow, even for a 20 db tap, the minimum signal loss at the MoCA frequencies is still 1.3 db or a 35% loss per tap. Not to mention losses at the higher frequencies used by the SWiM.

I'd have to say numbers like these will never work for a DSWM13 based DRE system without an extraordinarily hot signal from the DSWM.


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## AntAltMike (Nov 21, 2004)

A few years ago, I inherited a DirecTV stacked trunkline system that had humongous amplifiers at the top of each stack of cable closets, and had enough multiport taps on each floor to support each apartment (back when cable TV was still 60 channel analog with three, beeping scrambled, "premium" channels, desperate condo HOAs would actually pay for something like that). In the top floor closet, they used a 4 port by -16dB tap, and then typically two, four port by -12dB taps all the way down, resulting in a structural differential of about 30dB between the strongest and weakest ports. Incredibly, it worked, sort of. Actually, it usually worked, but it didn't take much to upset it. I wound up doing "wing it" modifications to all three buildings in this complex where I would first split the vertical trunk loop and turn the amp down (they were rated for -0dBm but had been cranked above that), and then, in any follow-up service calls, I'd be sure to bring a couple of extra high frequency splitters or low value trunk taps to further split and roughly balance the system. One good thing about digital signals is that as long as you have enough signal to work with, you have a pretty wide operating window. Digital receivers can work with signals of maybe -20dBm to -65dBm, so when a DBS company demands that a system be engineered for -30 to -55 dBm levels, that system has the robustness to withstand some kinked wires and under performing splitters, as well as reflections from resident-installed add-ons.

Unfortunately for riser loop-wired hotels, however, you aren't going to have as much margin to work with, and it is impractical to have midpoint amplification on vertical wallplate wiring, whereas it is practical to have midpoint amplification on a vertical loop trunk, where the amplifier would be in a communications or telephone closet.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> Alright;
> 
> Because wow, even for a 20 db tap, the minimum signal loss at the MoCA frequencies is still 1.3 db or a 35% loss per tap. Not to mention losses at the higher frequencies used by the SWiM.
> 
> I'd have to say numbers like these will never work for a DSWM13 based DRE system without an extraordinarily hot signal from the DSWM.


VOS said that to connect an AIM to a DSWM13 a 10 db pad was required. If the max input rating for a receiver is -20 dbm, it is likely similar for an AIM. So the output of a DSWM13 is probably in the neighborhood of -10 dbm. That "extraordinarily hot" enough for ya?  MoCA doesn't get the benefit of extra hot output as the receivers and DECA adapter are the transmitters, but since it is using lower frequencies it experiences less loss through coax and passives.

That may explain what VOS said about how it could have been a DSWM15 if it weren't for MoCA losses. There's still frequency headroom for more SWM channels, as well as signal headroom for a couple more taps based on their -10 dbm output - though 15 would be the max possible due to the 16 node MoCA limit. The problem with this theory is that MoCA is already at a very high power. That's why you need a BSF on receivers that don't have a DECA capable tuner. The MoCA standard specifies a signal power range between -1 and +7 dbm in the 'E' band that Directv uses, based on http://www.mocalliance.org/marketing/specification/MoCA_Specification_for_Device_RF_Characteristics.pdf. I believe that should be representative of Directv's implementation because it specifically describes the characteristics of Directv's 2.3 MHz SWM control signal in the tables at the end.

If it really is being transmitted that strongly, and there's less loss at those frequencies, then why is MoCA the limiting factor? The receiver sensitivity graph for E band shows a signal of -49 dbm is required for the maximum PHY rate. But in this application, who cares about the maximum rate, they aren't doing MRV, there would be little data exchange so the minimum PHY rate of 57 Mb would be acceptable, which requires as little as -66 dbm at the receiver! I'm still missing something.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> If it really is being transmitted that strongly, and there's less loss at those frequencies, then why is MoCA the limiting factor? The receiver sensitivity graph for E band shows a signal of -49 dbm is required for the maximum PHY rate. But in this application, who cares about the maximum rate, they aren't doing MRV, there would be little data exchange so the minimum PHY rate of 57 Mb would be acceptable, which requires as little as -66 dbm at the receiver! I'm still missing something.


DECA starts degrading above 45 dB of loss.
"Non loop thru" DRE spec'd -45 dBm at the receiver.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> DECA starts degrading above 45 dB of loss.
> "Non loop thru" DRE spec'd -45 dBm at the receiver.


Well yeah VOS;

But (even though the graph in that link shows the min. sensitivity as -49 dbm before MoCA data rate degradation), that is the min. MoCA signal level for max. PHY data rate.

However as slice points out since there is no MRV streaming needed over the MoCA links of a DRE system, or the closest need would be maybe VODs which guests are trying to watch in near real time, is maintaining the max. PHY rate for MoCA even necessary?


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## Diana C (Mar 30, 2007)

HoTat2 said:


> Well yeah VOS;
> 
> But (even though the graph in that link shows the min. sensitivity as -49 dbm before MoCA data rate degradation), that is the min. MoCA signal level for max. PHY data rate.
> 
> However as slice points out since there is no MRV streaming needed over the MoCA links of a DRE system, or the closest need would be maybe VODs which guests are trying to watch in near real time, is maintaining the max. PHY rate for MoCA even necessary?


I think you may have answered your own question. Since MOCA is an implementation of old-style buss Ethernet (as opposed to the twisted pair star approach) the transfer rate on the wire is shared by all nodes on the segment. To support multiple VOD streams you are going to need something close to max data rate of MOCA.


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## slice1900 (Feb 14, 2013)

Yeah, I didn't take VOD into account. I guess DRE makes it work so a guest can order a movie, stream it over the internet to his receiver, and does the integration with the hotel's billing system so it is charged to his room?


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## Stuart Sweet (Jun 19, 2006)

On Demand isn't part of the equation at this time. It will be part of a future expansion.


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## HoTat2 (Nov 16, 2005)

slice1900 said:


> Yeah, I didn't take VOD into account. I guess DRE makes it work so a guest can order a movie, stream it over the internet to his receiver, and does the integration with the hotel's billing system so it is charged to his room?


OK Stuart;

But I still guess I did answer my own question to some extent for when VOD is added later on ... duh ,,,

13 rooms on what is essentially a bus architecture with possible multiple VOD program steams active on it at some future point would be best served by maintaining a max. PHY rate for the MoCA network.


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## Stuart Sweet (Jun 19, 2006)

As I understand it, you're on the right track.


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## damondlt (Feb 27, 2006)

I guess my only question is, would this system be installed in my bed and breakfast /sports bar.? It's only 10 rooms, but there will be a total of 30 tvs on the property? 

Sent from my PantechP8010 using DBSTalk mobile app


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## Stuart Sweet (Jun 19, 2006)

Yes, your b&b would be a great candidate for this. I would contact your favorite DRE-certified DIRECTV for Business dealer.


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## peds48 (Jan 11, 2008)

Stuart Sweet said:


> Yes, your b&b would be a great candidate for this. I would contact your favorite DRE-certified DIRECTV for Business dealer.


SolidSignal.com is a great place for this


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## damondlt (Feb 27, 2006)

Sent from my PantechP8010 using DBSTalk mobile app


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## damondlt (Feb 27, 2006)

Stuart Sweet said:


> Yes, your b&b would be a great candidate for this. I would contact your favorite DRE-certified DIRECTV for Business dealer.





damondlt said:


> Yes soon. The building is only half built lolSent from my PantechP8010 using DBSTalk mobile app


Sent from my PantechP8010 using DBSTalk mobile app


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## JosephB (Nov 14, 2005)

Also, on the DECA limitation side of things, it seems to me this doesn't require re-engineering MoCA. Just use a standard DirecTV-frequency-compatible MoCA implementation. If you go above 13/14 nodes + the distance limitation, not only are you re-engineering SWM, you have to get into re-engineering MoCA, which probably is cost prohibitive (or at the very least not worth any net gain in distance or nodes they might be able to squeeze in). So, even if bandwidth for IP traffic weren't a factor, I would imagine they'd stop there just because that's the MoCA node and distance limit.


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## slice1900 (Feb 14, 2013)

Well, "theoretically" they could support a longer loop, if they had a DSWM capable of 16 or more SWM channels and wanted to use it in a loop configuration.

The system would be set up like it is now, but 13 (or fewer) rooms from the end of the coax they'd have a BSF followed by another DECA. You'd need to have cat5 back to the equipment closet available for that second DECA for this to work (that's the gotcha that would make this too much of a niche solution)

With more rooms you'd need an even stronger SWM output and higher valued taps, so you'd get fewer than 13 rooms on the first half of the loop due to the bigger DECA losses from those high valued taps, but the second half could have up to the full 13 since that segment would replicate whatever tap values they use with the current loop of 13.


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## Stuart Sweet (Jun 19, 2006)

By Jove, I think he's got it!


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## veryoldschool (Dec 10, 2006)

Stuart Sweet said:


> By Jove, I think he's got it!


If only someone had a design for a stand alone amp for the DECA.


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## Stuart Sweet (Jun 19, 2006)

Yeah, you think that would be a no brainer.


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## slice1900 (Feb 14, 2013)

Wouldn't the following work?

1) A NAS diplexer on each end, facing in opposite directions, with a cable connecting the SAT output of each (SWM bypass)

2) The input of a splitter connected to the ANT output of each diplexer

3) One cable/OTA amp for each splitter output, linking it to the output of the other splitter, but with the amps running in opposite directions

The amps will boost the DECA signal on their output, but output nothing from their input. Thus each splitter would be a splitter for DECA traffic going one way and a combiner when going the other. Not as convenient or cheap as an integrated solution would be, but if you had a need to amplify DECA it would be worth trying unless there's an obvious flaw to this goofy little circuit that I'm missing.


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## Diana C (Mar 30, 2007)

I'm afraid there is more involved with extending MoCA than just signal levels. One of the key criteria for a data network is the bit error rate (BER). BER is typically stated as a power of ten, where the smaller the power (which is a negative number), the lower the error rate. Standard 100Mb/s twisted pair ethernet generally delivers a BER of 10^-13 or better. At that rate, a user will typically experience a bad packet once a week. At a BER 10^-12 the user will experience a bad packet about once a day. The problem with simply amplifing a LAN signal is that it has the effect of increasing the BER (at least until someone designs an amplifier with absolutely zero distortion). Bit errors are cumulative...you might get away with one "amplification" but two would likely get into totally unacceptable error rates. As the BER increases, packets must be retransmitted which reduces throughput. Wireless networks typically have much higher BERs than wired networks, which is why most wireless LANs never reach more than about 75% of their theoretical throughput. 

What you would really need is a repeater - something that would actually regenerate the packets on the next segment. A DECA is basically a repeater (well, technically a bridge since it connects two different topologies) as are switches (repeating the packet on only the destination segment) and hubs (which repeat the packet on all attached segments). Because the packet is received, the data is extracted, inserted into a new packet and the new packet transmitted the BER is preserved. Theoretically, one could build a MoCA repreater, but given the smaller market size, using a MoCA to ethernet bridge (e.g. a DECA) and a switch is the far cheaper way to go. In fact, a DECA and a switch are probably cheaper than an amplifier of acceptable quality would be.


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## Go Beavs (Nov 18, 2008)

Diana C said:


> _-snip-_
> 
> Theoretically, one could build a MoCA repreater, but given the smaller market size, using a MoCA to ethernet bridge (e.g. a DECA) and a switch is the far cheaper way to go. *In fact, a DECA and a switch are probably cheaper than an amplifier of acceptable quality would be.*


Would it be possible to simply connect two DECA modules together with an ethernet crossover cable to create your repeater? So, eliminating the switch?


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## Stuart Sweet (Jun 19, 2006)

My suspicion here is the latency created would be too much of a problem.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Wouldn't the following work?


You'll need to make a drawing for me to follow this and comment.


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## veryoldschool (Dec 10, 2006)

Diana C said:


> I'm afraid there is more involved with extending MoCA than just signal levels.


"but" this is modulated RF where the SNR defines the performance.
Wireless is RF "but" multipath prone.


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## veryoldschool (Dec 10, 2006)

Go Beavs said:


> Would it be possible to simply connect two DECA modules together with an ethernet crossover cable to create your repeater? So, eliminating the switch?


This wouldn't be much different than when using two SWiM-16s and CCKs to combine them.
It wouldn't fit too well with the DSWM13 due to requiring AC power midway on the coax loop through.


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## Go Beavs (Nov 18, 2008)

veryoldschool said:


> This wouldn't be much different than when using two SWiM-16s and CCKs to combine them.
> It wouldn't fit too well with the DSWM13 due to requiring AC power midway on the coax loop through.


Yeah, in the context of an MDU setting, it's not very useful. Too many cords to plug in.


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## veryoldschool (Dec 10, 2006)

Go Beavs said:


> Yeah, in the context of an MDU setting, it's not very useful. Too many cords to plug in.


Or simply not having a outlet where you need them.


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## Diana C (Mar 30, 2007)

veryoldschool said:


> "but" this is modulated RF where the SNR defines the performance.
> Wireless is RF "but" multipath prone.


True, and I'm honestly out of my depth in RF once we get beyond frequency/wavelength and encoding scheme. However, a MoCA packet looks pretty much like a standard ethernet packet. I suppose you *could* get away with more straight amplification before the distortion of the signal introduced an unacceptable number of bit errors. Do you know how dense the encoding of bits (the number of bits per frequency cycle) onto the carrier is in MoCA? The denser the encoding the more likely you are to have errors. This is the same as satellite transmission. In the old days, satellites used DPSK and 7/8 FEC. Now we are up to 8PSK and, as a result, FEC has to be increased to 3/4. Obviously, MoCA doesn't use FEC since a lost or corrupted packet can be retransmitted, but every retransmission slows down the link. In addition, since MoCA is a two way communications channel, latency (as Stuart points out) becomes an issue...if latency grows too much, the receiving station assumes the packet was lost and requests retransmission.


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## HoTat2 (Nov 16, 2005)

Stuart Sweet said:


> My suspicion here is the latency created would be too much of a problem.


And related to this I would think the amplifier outputs would need some type of isolation circuitry so the MoCA signals headed in the opposite direction would just see a terminating impedance instead of being fed to an amplifier's output and causing problems.

These isolators would cause even additional latency I would imagine.


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> And related to this I would think the amplifier outputs would need some type of isolation circuitry so the MoCA signals headed in the opposite direction would just see a terminating impedance instead of being fed to an amplifier's output and causing problems.
> 
> These isolators would cause even additional latency I would imagine.


There are a number of things you need to deal with, but in a design I came up with some time back, "latency" isn't one of them.


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## HoTat2 (Nov 16, 2005)

Diana C said:


> True, and I'm honestly out of my depth in RF once we get beyond frequency/wavelength and encoding scheme. However, a MoCA packet looks pretty much like a standard ethernet packet. I suppose you *could* get away with more straight amplification before the distortion of the signal introduced an unacceptable number of bit errors. Do you know how dense the encoding of bits (the number of bits per frequency cycle) onto the carrier is in MoCA? The denser the encoding the more likely you are to have errors. This is the same as satellite transmission. In the old days, satellites used DPSK and 7/8 FEC. Now we are up to 8PSK and, as a result, FEC has to be increased to 3/4. ...


MoCA actually uses not a single carrier, but many of them. 224 to be precise in a form of OFDM modulation called "Adaptive Constellation Multi-Tone" (or ACMT).

And it distributes the bits of a MoCA packet over them to varying levels depending upon how channel conditions between two MoCA nodes involved in a communication are affecting any particular carrier in the group. Greater bit loading up to a maximum of 256 QAM for carriers experiencing little attenuation or other impairments, down to BPSK for those experiencing the most.

For instance;



















> Obviously, MoCA doesn't use FEC since a lost or corrupted packet can be retransmitted, but every retransmission slows down the link. In addition, since MoCA is a two way communications channel, latency (as Stuart points out) becomes an issue...if latency grows too much, the receiving station assumes the packet was lost and requests retransmission.


Actually MoCA packets do use FEC, Reed-Solomon coding to be specific for MoCA 1.X.,

See following the MAC frame in the illustration









Note:

IFG - Inter-Frame Gap
CE Symbols - Channel Estimation Symbols


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## JosephB (Nov 14, 2005)

Go Beavs said:


> Would it be possible to simply connect two DECA modules together with an ethernet crossover cable to create your repeater? So, eliminating the switch?


Yes, this would be a kludgy way of doing it, but it would work. If I were DirecTV and wanted to create a "DECA repeater" that would be the way I'd do it, internally.



Stuart Sweet said:


> My suspicion here is the latency created would be too much of a problem.


The latency introduced by going through a bridge like that is going to be on the order of just a couple of milliseconds, well within the expected timeout limits. For example, the default timeout for the Apache HTTP server is 5 seconds. Even when they move to VOD in the DRE, the latency won't be a problem since it doesn't matter how long a video packet takes to get to the receiver, just that they all arrive in order and within an appropriate time of each other, not of when they were sent.



Diana C said:


> What you would really need is a repeater - something that would actually regenerate the packets on the next segment. A DECA is basically a repeater (well, technically a bridge since it connects two different topologies) as are switches (repeating the packet on only the destination segment) and hubs (which repeat the packet on all attached segments). Because the packet is received, the data is extracted, inserted into a new packet and the new packet transmitted the BER is preserved. Theoretically, one could build a MoCA repreater, but given the smaller market size, using a MoCA to ethernet bridge (e.g. a DECA) and a switch is the far cheaper way to go. In fact, a DECA and a switch are probably cheaper than an amplifier of acceptable quality would be.


And of course I'm not a networking hardware engineer but we're not even talking about mangling the packets. A MoCA bridge just takes an ethernet frame, turns it into a MoCA frame, and then back. At a block level, it shouldn't be difficult to build a repeater like suggested earlier that is simply MoCA to ethernet to MoCA in one box, but if you're going to draw your own circuitry and make your own box it wouldn't be hard to just pass the MoCA frame from the incoming radio to the outgoing radio without changing it to ethernet in between.


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## veryoldschool (Dec 10, 2006)

JosephB said:


> if you're going to draw your own circuitry and make your own box* it wouldn't be hard to just pass the MoCA frame from the incoming radio to the outgoing radio* without changing it to ethernet in between.


Perhaps you know something I don't, but "wouldn't be hard" doesn't seem to fit with a bidirectional RF signal.


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## JosephB (Nov 14, 2005)

veryoldschool said:


> Perhaps you know something I don't, but "wouldn't be hard" doesn't seem to fit with a bidirectional RF signal.


Well, let me rephrase to "shouldn't be hard" but we're talking about actively repeating a MoCA signal. The first suggestion was simply to put two MoCA bridges with an Ethernet cable between them. That would work, and would be easy and fairly cheap, but it would be "kludgy" to build in the field like that.

My suggestion was then that they could build a device that was effectively two MoCA to ethernet bridges, with the ethernet segment hardwired together, in one box. You'd basically have an F connector in and F connector out.

The next step would be, though, that you just eliminate the MoCA to ethernet conversion. The MoCA radio on one end sends the frame to some IC that does what it needs to do to put the frame out on Ethernet, and then the reverse happens in the second bridge and then the frame is passed to the MoCA radio to be sent out. It's not really a stretch to think that you could just pass the MoCA frame between the two radios without doing the Ethernet conversion between them.


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## veryoldschool (Dec 10, 2006)

JosephB said:


> Well, let me rephrase to "shouldn't be hard" but we're talking about actively repeating a MoCA signal. The first suggestion was simply to put two MoCA bridges with an Ethernet cable between them. That would work, and would be easy and fairly cheap, but it would be "kludgy" to build in the field like that.
> 
> My suggestion was then that they could build a device that was effectively two MoCA to ethernet bridges, with the ethernet segment hardwired together, in one box. You'd basically have an F connector in and F connector out.
> 
> The next step would be, though, that you just eliminate the MoCA to ethernet conversion. The MoCA radio on one end sends the frame to some IC that does what it needs to do to put the frame out on Ethernet, and then the reverse happens in the second bridge and then the frame is passed to the MoCA radio to be sent out. It's not really a stretch to think that you could just pass the MoCA frame between the two radios without doing the Ethernet conversion between them.


I followed all but your "next step", which I believe would require a new chip, "or" deal with a bidirectional RF amplifier and skip the MoCA chip.


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## slice1900 (Feb 14, 2013)

Inside the DECA adapter there is a DECA receiver/transmitter, and an ethernet PHY/MII (transmitter/receiver) The receiver of one is connected to the transmitter of the other. Instead, you build it with two DECA receiver/transmitters and connect it in the same way.

MoCA 1.1 supports combining multiple ethernet sized frames into one packet, so there's a little logic in between the two in the DECA adapter that has to deal with that stuff. However, connecting two receivers of the same time back to back like we're discussing simplifies matters, so it should be fairly easy for Directv to design/build if they wished.

My question is, would it need to be powered? A DECA connected to a receiver doesn't need to be, but does if used as a CCK. Not sure where it is drawing power from when it is connected to a receiver.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> My question is, would it need to be powered? A DECA connected to a receiver doesn't need to be, but does if used as a CCK. Not sure where it is drawing power from when it is connected to a receiver.


The SAT input.


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## slice1900 (Feb 14, 2013)

Does the receiver detect the DECA somehow and start providing a bit of DC power?


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Does the receiver detect the DECA somehow and start providing a bit of DC power?


seems unlikely


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## inkahauts (Nov 13, 2006)

I was under the impression that is was using the power that is output through sat one input that would have driven the lnbs of legacy dishes (or multi switches like the wvb8), but that that power was blocked at a swim because it wasn't strong enough to drvie swim, but they figured out it was strong enough to drive deca. 

But it's been so dang long since that conversation... Not sure its right. I just am thinking that it may be.


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## slice1900 (Feb 14, 2013)

I suppose it must. I guess the only receivers that would need to power a DECA are DECA capable but don't have DECA builtin. Those are all legacy capable and are thus capable of providing DC power. That must be why the DECA power supply is 18v.

So I can see how you'd power this hypothetical DECA repeater, but if you wanted to power it remotely (say by injecting power at the SWM output) it is going to end up as ugly as my idea for a DECA amplifier. Or at least the solution I see involves two diplexers, two dual passing splitters and a crossover cable


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> So I can see how you'd power this hypothetical DECA repeater, but if you wanted to power it remotely (say by injecting power at the SWM output) it is going to end up as ugly as my idea for a DECA amplifier. Or at least the solution I see involves two diplexers, two dual passing splitters and a crossover cable


I have yet "to see" how any of this would work, and remember the DECA needs power on its back end.


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## slice1900 (Feb 14, 2013)

If I could easily draw a picture I would, but I'll try to describe it...

Let's say you have a long run, and want to add a 'DECA repeater' to regenerate the signal back to its original strength at a certain point. At the SWM, you inject DC power by having the SWM output go into a diode steering splitter's output (i.e. the splitter is acting as a combiner) and the other output fed from a PI21 or similar, and the input connects to the cable continuing on to feed the receivers.

Next, you insure any intervening splitters along the way to where you want to add the 'repeater' use the red port so the power can get there. At the location you want to add the repeater you cut the cable and install connectors. Let's call the cable end on the side where the SWM signal and power originates the "from" side, making the other the "to" side.

You take two NAS diplexers, and connect the SAT+ANT port of each to the "from" and "to" cable ends. Each diplexer's ANT port connects to the non-pigtail end of a DECA. The network ports of the DECAs are connected with a crossover cable.

Power is needed on the pigtail end of the DECAs which normally connect to a receiver. For that you connect a dual passing splitter "A" to the SAT port of the "from" side diplexer. One output of splitter "A" is connected to the SAT port of the "to" side diplexer. The other output of splitter "A" is connected to a second dual passing splitter "B", and the pigtails of the two DECAs are connected to splitter B's two outputs.

You'd lose around 10db on SWM, between the diode steering splitter, splitter "A" and the two diplexers, so you might need to amplify your SWM after all this. There might be a better way to do this with less loss, but if not since you have power on the line you could add a SWM amp while you're at it


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## Diana C (Mar 30, 2007)

If the goal is to create a MoCA repeater, you have to decode the incoming signal back to digital data and then re-encode it onto the RF carriers (thanks HoTat2 for the details about MoCA's encoding).

IMHO, the real trick is that any solution has to be able to be powered over the coaxial cable without impacting the other devices attached to it. As Slice1900 points out, you can send the power over the coax. However, it might be an interesting engineering project to balance the power demands of two RF transceivers and the associated modems without blowing the inputs on the attached satellite receivers. The simplest solution would be to put power blocking diodes in the splitters, so that power flows down the trunk line but not to any of the room taps, but not sure how that will work with other bits that already need to be in these splitters.

Of course, there might also be power loss issues incurred along the loop, but that should be manageable. I guess I come back to the original question: Why bother? The vast majority of hotels I stay in (and I travel a lot for work) have less than 25 rooms per floor...easily handled by two loops. This solution can earn DirecTV many millions without doing anything more than it does right now. This is perfect for the Marriott Courtyards, Hilton Garden Inns, Hyatt Places and all the other business traveller focused hotels scattered across the country.


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## lugnutathome (Apr 13, 2009)

So when you armchair engineers get done designing this DECA signal booster can anybody make a few? My home is a perfect test location for this. So far i am able to only combine two SWM legs via diplexers before the whole mesh loses adaquate signal strength. This is why I run nearly half my equipment on switched Ethernet bridged via a wireles CCK (in wired only mode) to the DECA cloud bank.

I have the bits and bandwidth to create and bridge 4 DECA clouds via an ethernet switch but lack motivation to do so since the current infrastructure works perfectly but. I would welcome a single cloud solution without bridging out to make it fizz.

Don "why am I always the abnormal guy?" Bolton


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## Stuart Sweet (Jun 19, 2006)

Look, I think this would be a great piece of equipment to have, but from what I've been told the demand isn't there. A highly placed vendor rep told me he thought the total market for something like this would be under 1,000.


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## veryoldschool (Dec 10, 2006)

Diana C said:


> I guess I come back to the original question: Why bother? The vast majority of hotels I stay in (and I travel a lot for work) have less than 25 rooms per floor...easily handled by two loops. This solution can earn DirecTV many millions without doing anything more than it does right now. *This is perfect for* the Marriott Courtyards, Hilton Garden Inns, Hyatt Places and all the other business traveller focused hotels scattered across the country.


Are you suggesting DirecTV did their homework to find how to get the most bang for their investment? :lol:


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## Diana C (Mar 30, 2007)

veryoldschool said:


> Are you suggesting DirecTV did their homework to find how to get the most bang for their investment? :lol:


Radical concept, huh?


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## slice1900 (Feb 14, 2013)

lugnutathome said:


> So when you armchair engineers get done designing this DECA signal booster can anybody make a few? My home is a perfect test location for this. So far i am able to only combine two SWM legs via diplexers before the whole mesh loses adaquate signal strength. This is why I run nearly half my equipment on switched Ethernet bridged via a wireles CCK (in wired only mode) to the DECA cloud bank.
> 
> I have the bits and bandwidth to create and bridge 4 DECA clouds via an ethernet switch but lack motivation to do so since the current infrastructure works perfectly but. I would welcome a single cloud solution without bridging out to make it fizz.
> 
> Don "why am I always the abnormal guy?" Bolton


Why do you want everything on one DECA cloud? There's no difference between four bridged clouds and one big cloud. But if you really want to do that, here's how. Since you have tried the diplexer solution you already own the diplexers, so if you have a couple DECAs you've pretty much got what you need for a simpler version of my design since you wouldn't need to inject power remotely.

Connect the SAT+ANT port of a NAS diplexer on either end of the coax segments you want to bridge. Connect the SAT ports together for a SWM bypass. Connect the ANT ports to the non-pigtail end of the DECAs. Connect the network ports of the DECAs with a crossover cable. Connect one DECA power supply to each pigtail. Optionally, a dual passing splitter could probably allow sharing one DECA power supply between the two DECAs, or a PI21 could be used...you'd have to experiment.

Whatever latency this provides would be at best only 100 microseconds better than using a switch to bridge the DECAs, because even the cheapest bargain basement switches have a latency no more than that. Given that Directv spec'ed the latency parameters in MRV to tolerate whatever latency two DECAs adds (i.e. two DVRs with DECAs communicating) I doubt that extra 100 microseconds is going to cause problems


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Why do you want everything on one DECA cloud?


The simplest reason is the receivers will monitor/test & report the quality of the network.
I know Don has 20 dB loss on some of these runs for DECA, while much less for the SAT signals.

"Your kludge" is adding more problems with signals levels than it would help.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> The simplest reason is the receivers will monitor/test & report the quality of the network.
> I know Don has 20 dB loss on some of these runs for DECA, while much less for the SAT signals.
> 
> "Your kludge" is adding more problems with signals levels than it would help.


I don't see how either bridging with a switch or using the "kludge" I updated for his situation would hurt signal levels. Either solution would in fact help immensely because the signal would be regenerated back to full strength.

When the RF signal is bridged to ethernet in a DECA, if it has sufficient strength when it reaches there you have fully recovered digital data being output on the ethernet side. When that perfect digital data comes into the ethernet side of the other DECA (whether via switch or crossover cable) it goes out the RF side at full strength, with the same "bits" represented as originally came from the source.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I don't see how....


I've spent a fair amount of time with Don.
If you have to breakout of the RF domain, and you have cat5 in place, why complicate it?


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## lugnutathome (Apr 13, 2009)

I get the concept but adding multiple stems and pieces plus unregulated power supplies, this is more like a science project. Cobbling together workarounds to a problem that shouldn't be in the first place. I'd be better off served adding a small workgroup switch and joining two diplexed cloud banks there with it passing a single line out to the main backbone switch.

With exception to my scope of a domicile, a DECA install *is* a single cloud. Extending it out via a 100mb Ethernet ports (theoretically at least) creates capacity constraints a normal Whole Home system would not have.

My switched Ethernet infrastructure has none of the capacity constraints, my DECA cloud also has none of them, however the bridge between the two is (again in theory) a constraint. I am just wanting what most DECA installs have which is a single cloud. Barring that I already have a perfectly functioning infrastructure plus the bits to isolate all my WH traffic into several clouds joined via their own switch all using regulated power supplies (not inserters) should I actually need to lift that traffic off my hardwired gigabit infrastructure.

It would be nice to be able to do that in a professional, approved manner and not the "science project" approach we are left with 

Don "and yes I have the bits to do as you suggest (minus the crossover cable) already" Bolton



slice1900 said:


> Why do you want everything on one DECA cloud? There's no difference between four bridged clouds and one big cloud. But if you really want to do that, here's how. Since you have tried the diplexer solution you already own the diplexers, so if you have a couple DECAs you've pretty much got what you need for a simpler version of my design since you wouldn't need to inject power remotely.
> 
> Connect the SAT+ANT port of a NAS diplexer on either end of the coax segments you want to bridge. Connect the SAT ports together for a SWM bypass. Connect the ANT ports to the non-pigtail end of the DECAs. Connect the network ports of the DECAs with a crossover cable. Connect one DECA power supply to each pigtail. Optionally, a dual passing splitter could probably allow sharing one DECA power supply between the two DECAs, or a PI21 could be used...you'd have to experiment.
> 
> Whatever latency this provides would be at best only 100 microseconds better than using a switch to bridge the DECAs, because even the cheapest bargain basement switches have a latency no more than that. Given that Directv spec'ed the latency parameters in MRV to tolerate whatever latency two DECAs adds (i.e. two DVRs with DECAs communicating) I doubt that extra 100 microseconds is going to cause problems


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## lugnutathome (Apr 13, 2009)

HMM. So the parts list here would be using the guts from two inline DECA adapters using a single gigabit Ethernet interface between the two and a dedicated power supply (not another inserter)

Seems easy to spec, for the most part uses existing internal assemblies just would need a housing specd (one that dissipates heat thank you). From my layman's perspective this would seem straightforward and fairly low cost to produce. Those of us that would require such would be wiling to pay for such a device as well. This would extend DECA to an "estate class" solution and in fact be a boon to the entire MOCA landscape IMNSHO 

slice1900: I do thank you for the insights

Don "One DECA to rule them all!" Bolton



slice1900 said:


> I don't see how either bridging with a switch or using the "kludge" I updated for his situation would hurt signal levels. Either solution would in fact help immensely because the signal would be regenerated back to full strength.
> 
> When the RF signal is bridged to ethernet in a DECA, if it has sufficient strength when it reaches there you have fully recovered digital data being output on the ethernet side. When that perfect digital data comes into the ethernet side of the other DECA (whether via switch or crossover cable) it goes out the RF side at full strength, with the same "bits" represented as originally came from the source.


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## veryoldschool (Dec 10, 2006)

lugnutathome said:


> This would extend DECA to an "estate class" solution and in fact be a boon to the entire MOCA landscape IMNSHO


Once you've broken out of the RF domain, you've split the cloud, so I'm not sure you'll have what you expect.
Working with dual SWiM-16s that bridge through CCKs is similar.
Each have their own cloud.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I've spent a fair amount of time with Don.
> If you have to breakout of the RF domain, and you have cat5 in place, why complicate it?


I don't think he should change a thing, since he said his current infrastructure "works perfectly".

I just told him what would be involved in creating a "DECA repeater" that he wishes he had - for a lot less money than the hypothetical integrated solution that Stuart says would only sell a thousand units, and would thus likely end up costing a thousand dollars


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I just told him what would be involved in creating a "DECA repeater" that he wishes he had - for a lot less money than the hypothetical integrated solution that Stuart says would only sell a thousand units, and would thus likely end up costing a thousand dollars


This isn't the first "roundup".
Stuart & I have worked on this for a couple of years, and :bang "just a few times". :lol:


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## Stuart Sweet (Jun 19, 2006)

Agreed, but always with respect and always as friends. I tend to look at the business case and I trust VOS to think about the engineering possibilities.


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## veryoldschool (Dec 10, 2006)

Stuart Sweet said:


> I trust VOS to think about the engineering possibilities.


Which has had me :bang "just a few times" as I try to sort them out. :lol:


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## HoTat2 (Nov 16, 2005)

lugnutathome said:


> ... Don "and yes I have the bits to do as you suggest (minus the crossover cable) already" Bolton


Minor point in all this;

But are crossover cables even needed any longer?

I thought all ethernet NICs today use auto sensing to establish transmit/receive paths between clients so straight ethernet cable connections are all that are required.


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## slice1900 (Feb 14, 2013)

HoTat2 said:


> Minor point in all this;
> 
> But are crossover cables even needed any longer?
> 
> I thought all ethernet NICs today use auto sensing to establish transmit/receive paths between clients so straight ethernet cable connections are all that are required.


I have no idea if that's true for the DECAs, so I figured better safe than sorry. With gigabit ethernet autosensing is mandatory, but it was optional for fast ethernet and that's what DECAs use.


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## Diana C (Mar 30, 2007)

slice1900 said:


> I don't see how either bridging with a switch or using the "kludge" I updated for his situation would hurt signal levels. Either solution would in fact help immensely because the signal would be regenerated back to full strength.
> 
> When the RF signal is bridged to ethernet in a DECA, if it has sufficient strength when it reaches there you have fully recovered digital data being output on the ethernet side. When that perfect digital data comes into the ethernet side of the other DECA (whether via switch or crossover cable) it goes out the RF side at full strength, with the same "bits" represented as originally came from the source.


But you still wouldn't have a single cloud. Once you disassemble a MOCA packet and place it on an ethernet segment you are no longer repeating, you are bridging. The MOCA cloud on the right of your "repeater" will be a different cloud than the one on the left. The MAC layer of the two MOCA segments will be separated by an ethernet segment, whether you have a switch, a hub or just a cable between the two DECAs. The receivers on one segment will not see the receivers on the other at the MAC layer, only at the transport layer. IOW whole home will work, but the network monitoring tools won't.


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## JosephB (Nov 14, 2005)

Diana C said:


> But you still wouldn't have a single cloud. Once you disassemble a MOCA packet and place it on an ethernet segment you are no longer repeating, you are bridging. The MOCA cloud on the right of your "repeater" will be a different cloud than the one on the left. The MAC layer of the two MOCA segments will be separated by an ethernet segment, whether you have a switch, a hub or just a cable between the two DECAs. The receivers on one segment will not see the receivers on the other at the MAC layer, only at the transport layer. IOW whole home will work, but the network monitoring tools won't.


Anything monitoring the *physical* layer wouldn't work, but you could still hit anything at Layer 2 of the OSI model or above. So, while you wouldn't be able to see signal levels and whatnot, you could still do anything that requires a MAC address, basically.


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## slice1900 (Feb 14, 2013)

Diana C said:


> But you still wouldn't have a single cloud. Once you disassemble a MOCA packet and place it on an ethernet segment you are no longer repeating, you are bridging. The MOCA cloud on the right of your "repeater" will be a different cloud than the one on the left. The MAC layer of the two MOCA segments will be separated by an ethernet segment, whether you have a switch, a hub or just a cable between the two DECAs. The receivers on one segment will not see the receivers on the other at the MAC layer, only at the transport layer. IOW whole home will work, but the network monitoring tools won't.


Using my kludge that's true. However, if the hypothetical DECA repeater was created, that's not necessarily the case. If the receiver on each end merely decodes the bits encoded in the RF signal and passes those to the transmitter on the other end so the exact same bits are sent out in the RF signal on that end, it is no different than an amplifier - better, actually, it would be a regenerative amplifier. In RF terms the equivalent of an AGC amp with a negative noise rating.

This device wouldn't show up as a DECA "node" and thus wouldn't even count against the limit of 16. The logical equivalent of a magical section of coax that strengthens the signal and reduces the noise back to the levels that were present at the original transmitter.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> if the hypothetical DECA repeater was created,
> This device wouldn't show up as a DECA "node"


And if cows could fly.....

I think this thread may have run its course.

We have a good idea of what the DSWM13 is and what it will be used for.

"What ifs" can go on forever, but will have little to no impact on anything.

SWiM & DECA have been spec'd to work well with each other.

There are limited situations where you can extend the range of SWiM with an amp and still have DECA function.

A DECA cloud can be combined between two SWiM-16s, but great attention must be paid to the losses to keep all the nodes and paths within range.


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## HoTat2 (Nov 16, 2005)

veryoldschool said:


> And if cows could fly.....
> 
> *I think this thread may have run its course.*


Well ...

At least until we get more specific details on the DSWM-13 such as it's new carrier frequencies, spacing, power requirements, and so forth ...


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## veryoldschool (Dec 10, 2006)

HoTat2 said:


> Well ...
> 
> At least until we get more specific details on the DSWM-13 such as it's new carrier frequencies, spacing, power requirements, and so forth ...


Frequencies & spacing has already been mentioned.
They start at the same frequency and the spacing is one half of the analog SWM.
The PI would seem to be the same 29 v.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Frequencies & spacing has already been mentioned.
> They start at the same frequency and the spacing is one half of the analog SWM.
> The PI would seem to be the same 29 v.


Spacing half of the analog SWM meaning channel centers are separated by ~51 MHz instead of 102 MHz? (i.e. 974, 1025, 1076, 1127, 1178, ... rather than 974, 1076, 1178, 1280, ...)

Or is the gap _between_ the transponders that are encapsulated in the SWM channels half the size, implying channel centers separated by ~69-71 MHz?

Just curious about the maximum number of channels this implementation is capable of. Whether we see DSWMs that take advantage of that is another matter of course - the analog SWM had room for two more channels than the 8 present in the SWM8/SWM16/SWM-LNB.

A SWM with even 16 channels could present a bigger problem for DECA if you had to split the signal more than 8 ways. Going beyond 16 channels would add additional complications.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Spacing half of the analog SWM...
> 
> A SWM with even 16 channels could present a bigger problem for DECA....


Until the specs are published [around Jan 15th] they won't be posted here [by me].
Transponder size hasn't changed so the change comes from the digital filters being able to have less space between the channels.

The current SWiM-16 handles DECA "just fine", so should there ever be 16 channels on one coax, it shouldn't present any significant problem.
In residential use, DVRs & Genies tend to "eat up" SWiM channels long before there is a problem with DECA.


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## Diana C (Mar 30, 2007)

JosephB said:


> Anything monitoring the *physical* layer wouldn't work, but you could still hit anything at Layer 2 of the OSI model or above. So, while you wouldn't be able to see signal levels and whatnot, you could still do anything that requires a MAC address, basically.


Exactly...each DECA is a node on a separate MOCA network.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Until the specs are published [around Jan 15th] they won't be posted here [by me].
> Transponder size hasn't changed so the change comes from the digital filters being able to have less space between the channels.
> 
> The current SWiM-16 handles DECA "just fine", so should there ever be 16 channels on one coax, it shouldn't present any significant problem.
> In residential use, DVRs & Genies tend to "eat up" SWiM channels long before there is a problem with DECA.


How much difference is there in loss between two devices attached to the same 8 way splitter on a SWM16's SWM1 (for simplicity, let's say SWM2 is terminated) versus two devices attached to separate 8 way splitters on SWM1 & SWM2? There is additional loss being added by not only the DECA bridge, but due to traveling through 2 splitters (one backwards and one forwards) instead of only suffering the port to port loss in one splitter. Is that right?

I guess in a DSWM with a lot of channels, if they make one with two outputs they may not put in a DECA bridge because it would make it too easy to exceed the 16 node limit, so you wouldn't have that problem.


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## inkahauts (Nov 13, 2006)

I'm sure there a ton of variables, but... In my system...

Swim16 output one goes to a two way splitter... One out goes to my My c42 the other to my wvb, then out of my wvb to my hr44. 

Output 2 from the swim16 goes directly to my HR34.

Both runs from the outputs of the swim are a minimum 120 feet long.

From my hr44 to my clients...

-8
-9

To my HR34..

-23


The mesh rate is between 275 and 285 from my hr44 to my wired client. From my hr44 to the wireless client or the HR34 its always between 245 and 255. 

So there definetly is a difference even with little to no splitters and around 250 feet between them when they cross through the swim16. 

Now I have no idea how that relates to actual db loss etc specifically that you are looking at, but maybe that will give you a bit of example. When I had once used an eight way splitter instead of a the two way and had more equipment hooked up the loss between sides with the same general lengths was slightly higher, closer to say -12 to -14, and speeds suffered slight as well, being less by 10 to 20 generally.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> How much difference is there in loss between two devices attached to the same 8 way splitter on a SWM16's SWM1 (for simplicity, let's say SWM2 is terminated) versus two devices attached to separate 8 way splitters on SWM1 & SWM2? There is additional loss being added by not only the DECA bridge, but due to traveling through 2 splitters (one backwards and one forwards) instead of only suffering the port to port loss in one splitter. Is that right?


As I've mentioned, the DECA loss budget is 45 dB before it starts to degrade.
Two 8-ways + the -16 crossover eats up about 32 dB.
This leaves about 275' of coax loss "end to end".
Bypass the -16 crossover and use diplexers to bridge and you can extend this another 100'.
Change to two 4-ways and you can extend this another 125'.
Four DVRs + Genie & three clients should be able to have 450' of coax "end to end".


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## slice1900 (Feb 14, 2013)

My question though is what is the difference between two receivers 'talking' across the same 8 way splitter, versus the same two receivers talking across the DECA bridge with each on a separate 8 way splitter? I would think it is adding more than just the bridge loss, because the signal has to travel through two 8 way splitters (in the first and out the second) instead of talking across ports on the same 8 way splitter.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> My question though is what is the difference between two receivers 'talking' ...


If the two receivers are within the loss budget of 45 dB, "none".

I think you grasping at trying to find a "need" for the DSWM13 technology in residential use.
I don't foresee it coming until it's done for reasons of cost [cheaper than the analog SWiM].
"I'd expect" it to move next into the MDU market, where a replacement for the SWiM-32 would be of use and DECA remains within each unit.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> If the two receivers are within the loss budget of 45 dB, "none".
> 
> I think you grasping at trying to find a "need" for the DSWM13 technology in residential use.
> I don't foresee it coming until it's done for reasons of cost [cheaper than the analog SWiM].
> "I'd expect" it to move next into the MDU market, where a replacement for the SWiM-32 would be of use and DECA remains within each unit.


I think you misunderstand why I'm asking the question.

What I'm thinking is that if they had a DSWM you'd have some instances using up to 16 way splitters (basically, anytime you have more than 8 devices connected) A DSWM with only one SWM output would not be problem, but one with dual outputs (similar to a SWM16) might be because the DECA would have to travel through both splitters and the internal bridge. By your measurements that would leave maybe 175' of coax, which could be tight in some cases, so maybe they wouldn't want to do a dual output DSWM (whenever they're ready to do a DSWM for residential market, whether that's next spring or sometime in 2015)

I have no idea what the DSWM costs them to make, other than the reason that it was designed in the first place was to be cheaper than the analog SWM (eventually) However, the DSWM has a low bar for residential use because having a DSWM LNB that was cheaper than a SWM16 and running four coaxes is a lot easier than a DSWM LNB that's cheaper than today's SWM LNB.


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## Stuart Sweet (Jun 19, 2006)

Why would you think that the reason the DSWM13 was created was cost savings?

What evidence do you have that this technology will ever cross over to residential?

Seems to me this technology was designed to help DIRECTV conquer the hotel market, and any other use is coincidental.

I'd like to see this cross over to sports bars, as it would make wiring faster, but DIRECTV has no problem getting customers in that market. 

I've said it before, it's fun to speculate but don't go thinking that it's a foregone conclusion that you'll ever see one of these at home.


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## slice1900 (Feb 14, 2013)

Perhaps not the DSWM13 specifically, but the DSWM technology in general. From a paper on the DSWM ASIC presented at ISSCC last February:



> The evolution of direct-to-home transmit/receive systems requires a solution to aggregate, switch and route signals from multiple satellites to multiple set-top boxes efficiently. Prior solutions required separate coax cables to carry signals from each low-noise block (LNB) to set-top boxes in the home, resulting in high installation cost. An existing solution called analog single-wire multiswitch (ASWM) channel stacking uses an analog frequency translation switch located near the antenna LNB to select and output signals from multiple LNB's to a fixed frequency slot for each set-top box on a single cable [1]. Although the ASWM solution solves the problem of multiple cables, it does not provide enough flexibility and capability to increase the number of inputs, and it requires multiple external components like SAW filters which in turn would significantly increase cost [2]. This paper introduces an integrated digital single-wire multiswitch (DSWM) channel-stacking IC implemented in 45nm CMOS, which uses digital signal processing after wideband 9b 1.82GS/s ADC's to select and reorder transponder channels. The selected and reordered channels are digitally upconverted and are stacked into L-band through a 9b 5.46GS/s DAC. It removes the need of in-band SAW filters, offers a full flexibility of channel selection, and supports many more satellites through a single L-band cable to set-top boxes at much lower cost and lower power consumption.


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## Stuart Sweet (Jun 19, 2006)

Theory... Yet to be seen if it will turn into practice. I know I seem like a perennial downer, but I'm not trying to be so much as I'm trying to bring you back into line with today's reality.

We know, for example, that the dswm needs more power than a traditional SWM.


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## slice1900 (Feb 14, 2013)

Power consumption is a not a big issue for a digital device because each successive process generation requires around half the power of the previous one for the same performance level. That's why you see iPhones running for hours on a tiny battery that have greater processing power than a circa 2001 Pentium 4 PC that could double as a room heater.

The 45nm technology used for the ASIC described in the paper is a bit out of date, current for foundry processes is 28nm and 20nm will be available for mass production in 2014. Aside from the LNB power (which is fixed) and whatever it draws for analog stuff like AGC amplification, the rest of the power draw is due to the DSWM ASIC and would be possible to cut by up to 75% in an updated version of the ASIC built in a 20nm process.

Using an older process for a product like the DSWM13 makes sense. As the first implementation of a DSWM in a very low volume product, there's no compelling reason to use a smaller process, and power consumption is unlikely to be a critical design criteria considering the DSWM13's target market.


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## Stuart Sweet (Jun 19, 2006)

I wish I could share your enthusiasm.


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## veryoldschool (Dec 10, 2006)

Stuart Sweet said:


> I wish I could share your enthusiasm.


The new chip will eventually become cheaper than the current chips with SAWs.


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## inkahauts (Nov 13, 2006)

Here's my question. Would dswim have worked if they didn't have such an evidently high power output that meant the requirement of taps, if it wasn't needing to be designed for such long runs?


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## HoTat2 (Nov 16, 2005)

inkahauts said:


> Here's my question. Would dswim have worked if they didn't have such an evidently high power output that meant the requirement of taps, if it wasn't needing to be designed for such long runs?


With maybe a 20-30 db external attenuator attached to it's output, I really don't see why a DSWM13 wouldn't work in a residential install with the usual SWIM splitter/home run cabling topology.

But it's purely DIRECTV's call here as to what market they want the DSWM13 limited to, since they would have to release the necessary firmware upgrades to residential receivers to allow them to communicate with the DSWM13 in lieu of its different SWM carrier frequencies, numbers and channel spacing.


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## slice1900 (Feb 14, 2013)

inkahauts said:


> Here's my question. Would dswim have worked if they didn't have such an evidently high power output that meant the requirement of taps, if it wasn't needing to be designed for such long runs?


Don't confuse DSWM as a technology with DSWM13 the product. They made specific choices for that product to increase the output level and restrict it to 13 channels, to meet the needs and limitations of the market it was targeted at.

I realize Stuart is skeptical, but I feel pretty confident that we will see other implementations of the DSWM technology. Targeted at a wider market, with more channels, and a normal output level. One can only guess when we might see them and which markets it might first appear for. There are several possible drivers:

1) cost - the technology should lead to lower cost products, but there's a catch (isn't there always!) There's likely to be a big price per unit crossover volume-wise between the analog SWM (low fixed cost for design, higher cost per unit to make) and DSWM (high fixed cost for design[*], lower cost per unit to make)

2) flexibility - the DSWM is mostly software. That is, most of what makes that ASIC implement a DSWM, rather than say speech recognition or MPEG4 compression is software. I'll toss out a bet that Doug Brott's firmware monitor starts showing DSWM firmware updates at some point. Maybe not for the DSWM13, but in less tightly controlled residential and commercial markets it opens up some interesting possibilities for Directv.

3) new satellites - if Directv broadcasts on BSS/RDBS frequencies, and needs to replace LNBs to make that happen, perhaps that makes a good place to switch to DSWM technology, assuming it meets their other needs/requirements at the time. Both the patent and the paper did mention the ability to support "many more satellites", though I think the implication is across all of Directv (i.e. DTV LA) and being able to share hardware as widely as possible.

[*] The reason it would have a high fixed cost for design, despite being a fairly run of the mill DSP-based ASIC, is because the mask set (think "blueprints") for anything built on a leading edge CMOS process costs a few million dollars. And that cost goes up 20-30% every two years. That's not design cost, that's the cost to take your design and put it into a form that the foundry that makes your chips requires. You pay maybe 10% of that for a trailing edge process like the 45nm CMOS the DSWM13 appears to have used - which is another reason why you'd use an older process for a low volume product. The worst part is, you pay this cost for every redesign, whether to take advantage of a new process (to make it smaller/cooler/cheaper or more powerful) or because you want to make a "newer" version (i.e. second or third generation DSWM from the patent) Even if you only change one tiny thing, you may pay a quarter million dollars to change one metal layer (one "page" of your blueprint)


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## Stuart Sweet (Jun 19, 2006)

inkahauts said:


> Here's my question. Would dswim have worked if they didn't have such an evidently high power output that meant the requirement of taps, if it wasn't needing to be designed for such long runs?


Remember that at least at this point, the DSWM is not supported by the residential software.

As for post #355, I will respond only to one point which is rooted in fact: The RedH firmware monitor only monitors STB software.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> Don't confuse DSWM as a technology with DSWM13 the product. They made specific choices for that product


I suggest you take your statement to heart.

"If cows could fly" has become a herd of flying cows.
Watch out for the cow droppings!

The DSWM is used for a specific market/application where more channels were needed on a single coax [loop through].

It's not because of a need for more SAT inputs, since the current SAT inputs aren't fully used, and there isn't a need for more channels with "home run" systems.

What we'll be using in 10 years is anyone's guess, "but" there must be a need for it first and the home market is being served now.


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## P Smith (Jul 25, 2002)

Stuart Sweet said:


> Remember that at least at this point, the DSWM is not supported by the residential software.
> 
> As for post #355, I will respond only to one point which is rooted in fact: *The RedH firmware monitor only monitors STB software.*


I would add a couple cents to that: and FW for clients distributing via STB like HR34/44, also for any part of installation if it will be organized as for clients (there is nothing new, dish doing that for third party devices like Archos PVP and own Q-Boxes).
If DTV will decide do that, we will see new IDs and digital stream's images for new components.


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## Stuart Sweet (Jun 19, 2006)

But P, you don't control the RedH Firmware Monitor and you can't say that those streams would appear there. You know better than anyone else that there is much more information in that satellite transmission than appears on redh.com.


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## P Smith (Jul 25, 2002)

No worry, everything under control.


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## slice1900 (Feb 14, 2013)

Stuart Sweet said:


> Remember that at least at this point, the DSWM is not supported by the residential software.
> 
> As for post #355, I will respond only to one point which is rooted in fact: The RedH firmware monitor only monitors STB software.


What is the COM23-600 shown in there? Isn't that some sort of headend device?

Whichever, you're correct if the RedH software doesn't look for or filters out DSWM software updates, should they be made available over the stream, they won't show up on Doug's site.


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## veryoldschool (Dec 10, 2006)

Who's Gary?


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> I suggest you take your statement to heart.
> 
> "If cows could fly" has become a herd of flying cows.
> Watch out for the cow droppings!
> ...


The reason the DSWM was originally designed does not have to have anything to do with its use in the DSWM13 for a specific market for those reasons to be valid for wider markets. The DSWM technology was certainly not designed for that specific niche market. There is not a single mention of high power outputs, using taps instead of splitters, or limiting the number of channels based on DECA losses or maximum number of DECA nodes in either the patents or the paper. There are other reasons given (cost, both of the DSWM and the receivers, as well as flexibility for more satellites) that while they have nothing to do with the DSWM13, don't mean that they aren't valid reasons why the DSWM technology was developed.

Its not as though it would be impossible for Directv to design a new version of the analog SWM with tighter channel spacing, thus allowing for more channels. It would be more expensive due to the better filters required, and you'd have more SAWs for the additional channels. It probably wasn't worth it for them to do for such a small market, which may be why they never did.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> Who's Gary?


I was thinking of Gary Toma, but Doug Brott who is operates that site. I've corrected that post


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## Stuart Sweet (Jun 19, 2006)

Slice1900, the COM23-600 is nothing. It's a listing that's been there for years and doesn't seem to correspond to anything that we've ever seen.

As for why the DSWM13 was invented, I'll ask as politely as possible, were you in the room at the time? Did you speak to people who were in the room at the time?

I certainly was not in the room at the time but I did speak to people who were, who told me that the DSWM13 was invented for the hotel market. I don't understand why you find that so difficult to believe. Think about how many hotels there are, and think about DIRECTV's market share there.

This isn't about a patent or a paper, it's about a real piece of equipment.


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## slice1900 (Feb 14, 2013)

I'm not saying the DSWM13 was not invented for the hotel market. It seems pretty clear from what you've told us about it and what you know from people you've talked to that it was developed for that one specific purpose, and won't be used elsewhere.

I'm talking about the DSWM technology. It was used to build the DSWM13 but can also be used to build other products. It remains to be seen where else and when it might be used, but based on the patents and the paper the DSWM technology was not originally designed for the hotel market, but was in fact designed to replace the analog SWM in the markets it is currently being used in.

If the DSWM technology had been designed specifically for that one niche market, why would they claim otherwise in those documents? If they wanted to keep what they were doing in the hotel market non-public for as long as possible, they would have simply said nothing.

Is it possible we'll never see it used in anything but the DSWM13? Sure, that's possible. Perhaps factors they did not anticipate have prevented the DSWM technology from being able to replace the analog SWM, but they were able to salvage something from an otherwise failed project by using it in the hotel market.


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## veryoldschool (Dec 10, 2006)

As I've posted earlier, just because there is a patent doesn't mean anything will come from it.
How many patents have never become anything?

"In this case" DSWM allows for DirecTV to move into a market they couldn't serve before, and requires unique software on the receivers .

I'm getting the feeling this thread may need an intervention.

I may do this by locking it until the DSWM13 specs get published, when the discussion can be about it.


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## Sixto (Nov 18, 2005)

veryoldschool said:


> Who's Gary?


Gary Toma, P., and Doctor J do an awesome job, for years. That data gets better and better.


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## slice1900 (Feb 14, 2013)

veryoldschool said:


> As I've posted earlier, just because there is a patent doesn't mean anything will come from it.
> How many patents have never become anything?
> 
> "In this case" DSWM allows for DirecTV to move into a market they couldn't serve before, and requires unique software on the receivers .
> ...


I'll start a new thread for DSWM speculation, to discuss the DSWM technology in general, and leave this one for the DSWM13 in particular. How's that sound?


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## inkahauts (Nov 13, 2006)

veryoldschool said:


> .....
> 
> It's not because of a need for more SAT inputs, since the current SAT inputs aren't fully used, and there isn't a need for more channels with "home run" systems.
> 
> What we'll be using in 10 years is anyone's guess, "but" there must be a need for it first and the home market is being served now.


But see that's the spot i tend to disagree looking forward three years from now.

By then I expect HR24 to become no recover like the HR20 etc. when that happens we will be left with just genies.

I have to believe by then they will allow Multiple genies if not sooner anyway. They really could use a lower cost solution for more than 10 channels than a swim16 once that happens IMHO.

That gives them three years before it could become a Mainstream issue by my guestimate.

While the number of people wanting two genies now likely is small the number if people wanting two DVRs in general is probably higher IMHO significantly. Not a exorbananr amount either way but enough that could Make them want to move to a larger swim.

Also porting this to mdu makes sense as well at some point if the cost savings is there. And then my question becomes relevant again. You don't need that kind of power for mdu either correct?

Again my question was simply does Dswim actually require higher output as the nature of the beast or is it pumped up do to its actual needs for its specific use in this specific product. Granted I doubt we know for sure. Hopefully we will know latter next month.


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## veryoldschool (Dec 10, 2006)

inkahauts said:


> But see that's the spot i tend to disagree looking forward three years from now.
> Again my question was simply does Dswim actually require higher output as the nature of the beast or is it pumped up do to its actual needs for its specific use in this specific product. Granted I doubt we know for sure. Hopefully we will know latter next month.


Let's see what comes down the pike before we start "worrying" about three years from now.

Yes, Genie's five tuners doesn't fit well with the analog tuner count.

The DSWM13 output is there for the application, and isn't "inherent" with DSWM.


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## veryoldschool (Dec 10, 2006)

slice1900 said:


> I'll start a new thread for DSWM speculation, to discuss the DSWM technology in general, and leave this one for the DSWM13 in particular. How's that sound?


I don't know of a moderator here that likes to close a thread.
It is a "tough call" for what adds to a thread and what derails it.

"I think" you might be better to start your own thread for your ideas and we'll keep this one "just a bit" closer to the DSWM13.


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## P Smith (Jul 25, 2002)

perhaps mods could move many (half ? :eek2 posts to that new thread


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## Stuart Sweet (Jun 19, 2006)

I'm closing this thread and I will open up a topic on DIRECTV Residential Experience with Loop-Thru (the legitimate use of the DSWM13 switch) in the installation forum.


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