# Converting MRV from Home Network to "Supported", and from legacy to SWiM



## GregAmy (Jan 7, 2008)

I've been reading my arse off on all these threads on DECA, MRV, SWiM, and the like. Jeez, I've learned a lot! But I'm still not completely clear on the exact path and equipment I need to convert from existing "unsupported" MRV-via-Ethernet to a "supported" DECA setup, and from "old tech" to SWiM. I'd like to summarize what I thin I'm supposed to do into one macro-post and get some feedback.

*Current situation:*
- Two HR22-100s and one HR21-700. Two coax going to each box.
- All receivers currently using "unsupported" MRV via Cat 5e Ethernet, all networked via retail-level Linksys router to a cable modem.
- I'll be adding a new receiver to a newly-refurbished detached garage, about 150 feet from my dish. To get there I will be running direct-burial cable, both RG6 and Ethernet, to the garage. I want to use MRV to the house, so I don't want a separate dish.
- The dish was installed many years ago, possibly 5-6 or more. It's an elliptical one, but with four coax coming down to a standard multiswitch (had to buy a replacement many years ago, seem to recall "WB68"?). Since I've got two coax going to each of the three receivers, it's reasonable (obvious?) to assume this is *not* a SWiM installation.

*The Conundrum:*
- What's the best way to get to DECA to improve MRV performance, and at the same time add the garage receiver with minimal expense and cables?
- I also want to design/install a system that will be compatible with the upcoming HR-34 powerhouse (I'm on monthly contract - been a DTV customer for nearly 15 years - and plan to leverage one of those for a contract renewal).

*My Thoughts:*
- Convert the system to SWiM first. As best I understand, all three of my existing receivers, and any add'l one I'm likely to get, are SWiM-compatible. I've seen "kits" on eBay for $80 that include the LNB, SWiM8 multiswitch, 8-way splitter and power supply. I've seen install drawings here that indicate all I'll need to do is connect one wire from the LNB (instead of the current four) to the SWiM8 multiswitch, then one from there to the power supply, then another one to the 8-way splitter, then from there a single coax to each receiver (and I remove both BSFs from each).

This is stuff that I can do myself, and at this point I will have converted the system to SWiM and reduced my coax-run count significantly.

Correct?

*Next step: convert the Ethernet MRV to DECA:*
- As I understand it, I will need one DECA for each HR21/22, since they do not have internal DECA. If the new fourth receiver turns out to be an HR24/25 I will *not* need a DECA for that one.
- Each HR21/22 DECA will connect one side to the incoming coax run, with the other end having one coax connection to the SWiM-in on the receiver, and the other to the Ethernet-in on the receiver. As I understand it, these DECA do *not* need power supplies, correct?
- An HR24/25, if that's what I get, will simply have one coax in, no DECA.
- I need to install one DECA that will be connected between my LinkSys router and a coax to the 8-way splitter. This DECA *will* need a power supply. I've seen reference on eBay for "DECABB1MR0-01 Internet Broad Band DECA Adapter", so it seems it's a different part. This DECA will be configured (or will it use DHCP?) to connect to the Internet via my router, and will be the gateway for the other receivers' Internet access. I'm guessing they set up a private network among themselves? Is it possible to configure this DECA manually, so that I can point to a different gateway? I have two Internet gateway on the same IP segment, with one used exclusively by my DTV and NetFlix equipment.

That's it, yes?

If this is the right design, then I can do this for $80 for the SWiM stuff, 3x$15 for the HR21/22 DECA, then about $25 for a DTV DECABB1MR0-01, or about $150 and an afternoon's worth of work. At that point I'll be all set for higher-performance MRV and ready go when it's time to add the new receiver in the garage.

So this is what I've learned perusing through all these posts, and I'm just looking for confirmation that I've got it all correct...

Thanks!

Useful links I've found:

Connected Home Installation Images 
http://www.dbstalk.com/showthread.php?t=177308

Whole Home DVR Service Information and FAQ
http://www.dbstalk.com/showthread.php?t=178068

SWM LNB with Splitter Install 
http://www.dbstalk.com/showthread.php?t=147347

Newbie/novice Needs Help Installing Whole Home DVR... 
http://www.dbstalk.com/showthread.php?t=197892


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## veryoldschool (Dec 10, 2006)

you currently have 3 DVRs [or six tuners] so a SWiM LNB, PI, and splitter should get you going for the SWiM part.
This will leave "room" for two more tuners. 
Each will need a white DECA [which are powered from the receiver] and a broad band [black] DECA to make the bridge to your home network. Not sure what is going to happen with two gateways. :shrug:

Now moving to the HR34 would require either dropping tuners, or changing over to a SWiM-16.


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## harsh (Jun 15, 2003)

What is required to change to a supported WHDS installation is a professional installation through DIRECTV. It may also be the cheapest way to attain a DECA network.

The problem I'd be watching for is the long distance run to the garage. With five splits, it may be interesting to get a 150' run.

Until you figure out what you ultimately want to do, I would recommend you add a small gigabit switch to replace the switch on your router. I'm imagining you'll want to run wired Ethernet to the garage anyway.


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## veryoldschool (Dec 10, 2006)

harsh said:


> What is required to change to a supported WHDS installation is a professional installation through DIRECTV.


It wasn't for me.


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## PokerJoker (Apr 12, 2008)

> . . . Convert the system to SWiM first. As best I understand, all three of my existing receivers, and any add'l one I'm likely to get, are SWiM-compatible.


That is correct. Converting to SWM is a good idea. Please note however that if you do the work yourself, the chances of getting it changed to a "supported" status at DirecTv are very low.



> I've seen "kits" on eBay for $80 that include the LNB, SWiM8 multiswitch, 8-way splitter and power supply. I've seen install drawings here that indicate all I'll need to do is connect one wire from the LNB (instead of the current four) to the SWiM8 multiswitch, then one from there to the power supply, then another one to the 8-way splitter, then from there a single coax to each receiver (and I remove both BSFs from each).


That is not quite correct. You can EITHER use your existing dish/LNB with its four coax runs, connected to a separate SWM8 switch, and from there to the 8 way splitter; OR you can change the LNB head on the dish to the SWM LNB type, and run one wire from it directly to the 8 way splitter. Essentially the SWM LNB has the SWM8 switch built-in. A SWM LNB and a SWM8 switch are never used together.

Reasons to use the one-wire SWM LNB: simplicity and lower cost. If you hire DirecTV to do the job, this is what they will install. They virtually never install a SWM8.

Reasons to use the existing 4-wire dish with a separate SWM8: expandability. With your fourth DVR going in, you will "use up" all the available capacity of a SWM LNB.  No further expansion will be possible in the future. If you keep the existing 4 wire dish and put in a SWM8, you will still be "using up" all of its capacity, but you have the option of changing it to a SWM16 in the future if you ever need to add another receiver, or if you ever want to get the new HR34 "super DVR".

Also, in your case, with a separate SWM8, you wouldn't have to mess with the dish at all, just change the inside wiring. Basically the SWM8 replaces your existing WB68 switch.



> *Next step: convert the Ethernet MRV to DECA:*
> - As I understand it, I will need one DECA for each HR21/22, since they do not have internal DECA. If the new fourth receiver turns out to be an HR24/25 I will *not* need a DECA for that one.


There is no such thing as an HR25. There is only an H25 receiver which is not a DVR.


> - Each HR21/22 DECA will connect one side to the incoming coax run, with the other end having one coax connection to the SWiM-in on the receiver, and the other to the Ethernet-in on the receiver. As I understand it, these DECA do *not* need power supplies, correct?


Correct. The DECA gets its power from the DVR via the coax.



> - An HR24/25, if that's what I get, will simply have one coax in, no DECA.


HR24 has built in DECA, no separate unit needed, be sure nothing is connected to the HR24 Ethernet jack.



> - I need to install one DECA that will be connected between my LinkSys router and a coax to the 8-way splitter. This DECA *will* need a power supply. I've seen reference on eBay for "DECABB1MR0-01 Internet Broad Band DECA Adapter", so it seems it's a different part. This DECA will be configured (or will it use DHCP?) to connect to the Internet via my router, and will be the gateway for the other receivers' Internet access. I'm guessing they set up a private network among themselves? Is it possible to configure this DECA manually, so that I can point to a different gateway? I have two Internet gateway on the same IP segment, with one used exclusively by my DTV and NetFlix equipment.


The separate BB DECA is a nice little black box which connects to a cable (from your splitter) on one side and connects to your router (via ethernet) on the other side. The DVRs usually use DHCP (from your existing system or router) to get addresses for themselves, meaning all the DVRs will show up on your network. They usually do not use a private network or separate subnet. However, you can turn off DHCP at each DVR and configure them manually, thus enabling most any arrangement you want to do.



> If this is the right design, then I can do this for $80 for the SWiM stuff, 3x$15 for the HR21/22 DECA, then about $25 for a DTV DECABB1MR0-01, or about $150 and an afternoon's worth of work. At that point I'll be all set for higher-performance MRV and ready go when it's time to add the new receiver in the garage.


Basically right. Use solid-copper RG6 if possible. Quad shield is not necessary. Use only compression-type RG6 fittings (preferably PPC EX6XL), never use crimp or twist-on! You will need a special coax stripper tool and compression tool, both available at Home Depot and Lowes, or online. Power off (unplug) all DVRs before doing the work. Then power them up one at a time and let each one finish booting before going on to the next.

Oh, and the SWM system (either LNB or SWM8) requires a power inserter to work. Be sure you get the right one.

Good luck with your project.

Keith


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## GregAmy (Jan 7, 2008)

Thanks for the tips, all.



PokerJoker said:


> Use only compression-type RG6 fittings (preferably PPC EX6XL), never use crimp or twist-on! You will need a special coax stripper tool and compression tool, both available at Home Depot and Lowes, or online.


Ugh, the whole house is crimp fittings; first installed here 2003. I can do this work, no prob, just need to get the tools. But, if I pay DTV are they going to rewire the whole house or just leave me with the crimp fittings? If the latter I certainly don't need to pay them for that... 

This is all good stuff, thanks.


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## harsh (Jun 15, 2003)

veryoldschool said:


> It wasn't for me.


It doesn't seem fair to pass the conditions of your installation off as typical.


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## veryoldschool (Dec 10, 2006)

harsh said:


> It doesn't seem fair to pass the conditions of your installation off as typical.


Says a Dish sub who doesn't have DirecTV. 
Maybe you should hold off until you have some first hand experience about this, huh? 
This wasn't "my installation", but "my phone call" to a CSR when I had MRV added to my account.


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## harsh (Jun 15, 2003)

veryoldschool said:


> This wasn't "my installation", but "my phone call" to a CSR when I had MRV added to my account.


So you're saying that any DIRECTV customer who calls up and says they have DECA up and running can get a supported WHDS installation marked on their account without having a visit from a professional installer?


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## Diana C (Mar 30, 2007)

harsh said:


> So you're saying that any DIRECTV customer who calls up and says they have DECA up and running can get a supported WHDS installation marked on their account without having a visit from a professional installer?


Yes. Worked that way for me. Not to mention that we have 2 H25s which ONLY work on a "supported" (SWM and DECA) configuration.


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## Scott Kocourek (Jun 13, 2009)

It worked for me too, I was on the phone for another reason and thought I would try. All I ask was "by the way,can you switch me over to supported whole home now that everything is SWiM and Deca?" It took all of a few seconds. I'm not sure what the difference is because there is slim to no chance that I'll be calling them for support anyway.


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## sigma1914 (Sep 5, 2006)

harsh said:


> So you're saying that any DIRECTV customer who calls up and says they have DECA up and running can get a supported WHDS installation marked on their account without having a visit from a professional installer?


Worked here, too. As usual, those of us with subscriptions have first hand knowledge of these things.


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## dennisj00 (Sep 27, 2007)

harsh said:


> So you're saying that any DIRECTV customer who calls up and says they have DECA up and running can get a supported WHDS installation marked on their account without having a visit from a professional installer?


I installed DECA for a friend and the phone call was easy to get 'supported'. This was around a year ago.


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## Bevostein (Feb 2, 2008)

GregAmy said:


> - I also want to design/install a system that will be compatible with the upcoming HR-34 powerhouse (I'm on monthly contract - been a DTV customer for nearly 15 years - and plan to leverage one of those for a contract renewal).


A word of caution, if you call up Directv and have professional installation done and make other changes to your account, you will likely reup for a two year commitment and come off your month to month contract. That would severely diminish your bargaining power for an HR34


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## Beerstalker (Feb 9, 2009)

Bevostein said:


> A word of caution, if you call up Directv and have professional installation done and make other changes to your account, you will likely reup for a two year commitment and come off your month to month contract. That would severely diminish your bargaining power for an HR34


Only if they have to replace a receiver. If no receivers are replaced then it does not start a new 2 year agreement.


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## veryoldschool (Dec 10, 2006)

Bevostein said:


> A word of caution, if you call up Directv and have professional installation done and make other changes to your account, you will likely reup for a two year commitment and come off your month to month contract. That would severely diminish your bargaining power for an HR34





Beerstalker said:


> Only if they have to replace a receiver. If no receivers are replaced then it does not start a new 2 year agreement.


Rarely do I "plus one" posts, but this needs it.
Should a receiver require upgrading, even for SWiM compatibility, it will trigger a programing commitment.
Should none require "upgrading" [as in a like for like replacement for a defective unit] then no programing commitment is incurred with the connected home upgrade.


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## dpeters11 (May 30, 2007)

And where you say HR24/25, keep in mind that there is no HR25 currently, just the H25.


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## poppo (Oct 10, 2006)

I'm sort of in the same position as the OPer. Unsupported MRV with 2 cables and ethernet to 3 HR20s on an older AT9 dish. Everything works great as is. However, I've been wanting to switch over to the SWiM/DECA thing, but it seems like I really need to get a new dish to do it right. 

So unless I can get a free upgrade somehow (I have been with them since 97), I guess I'll need to stick with what I have.


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## veryoldschool (Dec 10, 2006)

poppo said:


> I'm sort of in the same position as the OPer. Unsupported MRV with 2 cables and ethernet to 3 HR20s on an older AT9 dish. Everything works great as is. However, I've been wanting to switch over to the SWiM/DECA thing, but it seems like I really need to get a new dish to do it right.
> 
> So unless I can get a free upgrade somehow (I have been with them since 97), I guess I'll need to stick with what I have.


The AT-9 can't use the SWiM LNB [of the AU-9], so you'd need something like a SWM8 in addition, but really what you have works and why "fix it" if it ain't broke?
eBay might be a cheaper way to go for the parts, but hell some have gotten this upgrade for free, so it's worth a call.


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## poppo (Oct 10, 2006)

veryoldschool said:


> The AT-9 can't use the SWiM LNB [of the AU-9], so you'd need something like a SWM8 in addition, but really what you have works and why "fix it" if it ain't broke?


True, it does work. But I would not mind getting rid of some of the extra cabling and making it easier if I want to move things around later. Plus these HR20s are not going to last forever. Maybe after the HR34 is available I can get a free or low cost upgrade out of them.


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## GregAmy (Jan 7, 2008)

Thanks for the bumps on this; I'm still pondering what I want to do.

I'm leaning toward going with the existing dish and a SWM8, for reasons posted above. Last week we direct-buried a pair each of RG6 and CAT5e (a spare each in case something happens to one of them). So I can double-connect the new receiver in the garage without SWM. However, for some inexplicable reason, we neglected to run Cat5e up to the second floor where the receiver is going to be before sheetrocking. Just kicking myself...but all is not lost, and I can snake it up there with some effort.

So, I have no *immediate *need for SWM or DECA, but I'm thinking it might be the better way to go long-term, and fairly easy to implement.

GA


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## RunnerFL (Jan 5, 2006)

harsh said:


> What is required to change to a supported WHDS installation is a professional installation through DIRECTV.


Professional installation is not required at all.


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## RunnerFL (Jan 5, 2006)

harsh said:


> So you're saying that any DIRECTV customer who calls up and says they have DECA up and running can get a supported WHDS installation marked on their account without having a visit from a professional installer?


Yes, an actual DirecTV subscriber would know this. A Dish subscriber sticking his nose in a DirecTV thread would not.


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## GregAmy (Jan 7, 2008)

harsh said:


> I would recommend you add a small gigabit switch to replace the switch on your router. I'm imagining you'll want to run wired Ethernet to the garage anyway.


Just as a reference/side note, "no bueno" on the gigabit. I bought a small 5-port 10/100/1000 Netgear switch and all H21/22s connected 100MBit only.

GA


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## DarkLogix (Oct 21, 2011)

From what I can tell all the recivers only have a 10/100 eth port
so I don't seewhy deca would be better than just eth as its going to eth to reach teh deca.

and if you use a switch not a hub then its not going to slow the network as data on a switch only goes from source to destination not over all ports like a hub (ie OSI model layer 2 the MAC address table should be able to coordanate properly)

but it's D* "supported" so be it

the only thing a gig switch could help with is possible more memory and faster MAC table lookup (but you won't see that as it'll be in the nanoseconds)


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## RunnerFL (Jan 5, 2006)

DarkLogix said:


> From what I can tell all the recivers only have a 10/100 eth port


That is correct.



DarkLogix said:


> so I don't seewhy deca would be better than just eth as its going to eth to reach teh deca.


If you go with DECA on all of your units you are setting up a second network just for your DirecTV units. The DECA network won't interfere with your "regular" network and your "regular" network won't interfere with your DECA network. No collisions, no dropped packets, no bandwidth problems, etc.


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## DarkLogix (Oct 21, 2011)

If you use a switch not a hub then you won't have any collisions

http://en.wikipedia.org/wiki/Collision_domain

with a switch each port is a collision domain and is full duplex
if you use a hub then yes you'll have collisions which is why you should use switches

if your switch is functioning properly then they won't interfere anyway and if they were to then adding a BB deca would allow just as much interfereance

trust me on this I work with networks (I may be new to learing about SWM and deca but networks are what I do)

if anything you're expanding the collision domain with the use of deca so that you can have collisions between recivers


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> if anything you're expanding the collision domain with the use of deca so that you can have collisions between recivers


"Nope" as all DECAs communicate in the RF domain.

"Now" if all DirecTV receivers are connected to the same switch, and things are working correctly, this won't be any different than the DECA cloud, with a BB DECA bridging to your home network.

The only real difference would be when things aren't working correctly.


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## DarkLogix (Oct 21, 2011)

What I ment by that is does the Deca RF domain act as a Hub or a switch?

do the the deca's have frequencies that each picks to send on and then listen on all the others or is there a common send frenquency such that if 2 send at the same time they could have a collision?

I don't know the details of the frequencies the deca's use for send and recive but
if they all just send on the same range then they would also be reciving on that smae range and thus colliding
though if they then piece out the full rand to listen to all the channels that they aren't using then it would put a limit on the max number of deca's

or do they use one of the methods that cell/cablemodems use of TDMA


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## veryoldschool (Dec 10, 2006)

Looks like I may start needing a translator here. 
The DECA center frequency is 550 MHz, and has a bandwidth of 50 MHz.
Other than these, it really isn't known how they communicate. There is a 16 node limit, and a bit-rate exceeding 250 Mb/s.
It's fairly hard [impossible] for RF to "collide", since it is directional.
The whole DECA cloud needs to be seen as one device, and then it's outputs are very much like a switch.


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## poppo (Oct 10, 2006)

DarkLogix said:


> the only thing a gig switch could help with is possible more memory and faster MAC table lookup (but you won't see that as it'll be in the nanoseconds)


People do have other devices that they connect to their switch that can take advantage of the speed.

I have my 3 DVRs and namad connected to 4 ports, and all traffic between them runs along happily between themselves And I have my computer, server, etc. connected to it too, and they are gigabit and running happily between themselves at high speed.


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## DarkLogix (Oct 21, 2011)

well I know in cable internet they have to use TDMA/UCDMA to ensure that they don't send data in overlaping time segments

and that they can't send and recive on the same channels
DOCSIS uses the low channels (48Mhz and below, might be 64Mhz, for upstream and uses much higher channels for downstream)

in DOCSIS each 38Mbps channel is upto 6Mhz wide (older ones can be 3Mhz)
so if Deca's are all sending without some control mechanism to ether issue time slots to each or channels to each then it'll interfere with each other

if RF is directional then DOCSIS would be able to use the same for sending and reciving which would greatly up the bandwidth as the low channels tend to have noise issues

With that limit of 16 that tells me it likely has a control mechanism that ether pieces out the 50Mhz space or makes 1/16th second time slots (possibily goes through 16 time slots in some very short amount of time)


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## DarkLogix (Oct 21, 2011)

poppo said:


> People do have other devices that they connect to their switch that can take advantage of the speed.


Yes I was talking from a benefit to the reciver's angle


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## RunnerFL (Jan 5, 2006)

DarkLogix said:


> trust me on this I work with networks


As do I...



DarkLogix said:


> (I may be new to learing about SWM and deca but networks are what I do)


You should read up on SWiM and DECA before assuming you know how they work.


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## DarkLogix (Oct 21, 2011)

RunnerFL said:


> As do I...
> 
> You should read up on SWiM and DECA before assuming you know how they work.


Well if you're using plain ethernet with switches you won't have any collisions, dropped packets, ect

now if you use a HUB (which shouldn't even be sold anymore) then you can

I didn't assume how DECA's work but I know the issues you list will not occue in a network using switches
Please provide links to info on DECA's and SWiM so that I can read about it and see why its supposidly better


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> I didn't assume how DECA's work but I know...


For the same reason I don't profess to know networking, networking folks shouldn't try to grasp RF. Each has their own "rules/principals", but few are the same between them.


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## DarkLogix (Oct 21, 2011)

Read the rest of the sentance

I Know ethernet networking and I learn all I can about other forms
so I know that what he claimed about ethernet is wrong unless he's using gear which I wouldn't allow to touch any network I use

now on Deca I want to learn more but so far it seems like its similer to wifi but over a cable and wifi is one big collision domain (ie bad) I hope I'm wrong so I want to learn more

I do know quite abit about DOCSIS which is RF over coax (enough that I got board with that section of a forum) so RF isn't out of my grasp

so far
Its RF in the 550Mhz range with a 50Mhz width
it has over 250mbps of bandwidth

Now with what I know about Docsis there needs to be some method to avoid collisions as RF over Coax is not directional and will interfere with other signals in the same frequency

so I want to know what is the method to avoid colisions?

Docsis uses 2 very differant frequency ranges for send and receive and only the CMTS sends on the High frequencies and the CM's send on the low then via time slices it sections out which CM can speak to avoid multiple CM's from sending at the same time as that will cause collisions.

From what I've read so far Deca is very similer to Docsis but simpiler
so Please inform me of what I don't know.


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> Please inform me of what I don't know.


"I'm bored".
You seem to have a mindset based on networking that doesn't work well in the RF domain.
Perhaps others may be able to help you make some sense out of this.


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## DarkLogix (Oct 21, 2011)

well the knowledge I know has enabled me to trace a great many RF issues
from a faulty barrel connecter to a wet connection to a bad GB and many more

Sorry but I prefer to know more about how any networking device works
Networking is networking not just ethernet
Just because i say I know networking don't assume that I mean just RJ45 ethernet


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## veryoldschool (Dec 10, 2006)

So do you know how to use this?


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## DarkLogix (Oct 21, 2011)

Well how about a working pic
all I see is a red "X"


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## veryoldschool (Dec 10, 2006)

Guess the forum didn't like you. :lol:


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## DarkLogix (Oct 21, 2011)

Well when I pasted in the url of the red "X" I got a access denied message (ie don't have permission to view this page)

as for the smith chart I know the basics though haven't used it but after reading a little it simplifies some formerly fuzzy math though the fuzzy logic covers the issues that it would be used to fix

heres one for you if a barrel connector is loose and in water which range of frequencies will be most interfered with and which will pass with only slight degradation?

and what is the simple phrase that covers an easy way to remember?

btw if RF over was directional as you supposed earlier then that would mean that Comcast, Cox, Cisco, Charter, and every other cable internet provider is doing it wrong.


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## veryoldschool (Dec 10, 2006)

If RF wasn't directional, then there would be no directional couplers used with it.
http://www.solidsignal.com/pview.as...ase&utm_medium=organic&utm_source=google_base


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## DarkLogix (Oct 21, 2011)

Directional couplers are to ensure a known signal only goes the direction desiered, ie to isolate signals

2 signals at the same frenquency will interfere with each other
thus why forward and return can't be on the same channel

you had supposed that you could use the same ferinquency in both directions which you can't

It propogates from a source to a destenation as a broadcast along the carrier wire and when the signal from one end crosses the other if they're on close frenquencies then they'll have noise (thus the the reason for wight spaces)

I'm getting tired I came here to learn more not argue


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> Directional couplers are to ensure a known signal only goes the direction desiered, ie to isolate signals
> 
> 2 signals at the same frenquency will interfere with each other
> thus why forward and return can't be on the same channel
> ...


No, that wasn't it.
Directional couplers are not isolators, which is why I got bored a while back, with this.
"If you knew" RF, you'd know more about what I've been posting. Signals travel both directions, and why things like VSWR are measured.
The phase of the signal has so much to do with a lot of what is going on.
I can short the cable and still pass signal, if its at the right point [phase] of the wavelength. The same is true with an open, but 90º difference in phase.


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## DarkLogix (Oct 21, 2011)

Yes theres more than just frenquency there are various polizations and phases
circuler (L and R), H and V

but that doesn't cover which way the Deca permits two way compunication or if it does

there are litteraly hundreds of possible ways

in Docsis it covers the full range of the frequencies so all phases are used thus two way on the same channel isn't possible and due to doppler the waves skew (or widen) so white space is needed as differant frenquencies "drift" at slightly differant rates and a slope adjustment has to be done on their amps to correct it.
also due to the drifting in large cable systems it would be difficult to match the phases to utilize that for two way communication

so on Deca what is the spec of the RF its using?
is it issuing a differant phase to each for trasmitter?
is it using differant frequencies?
clearly slope adjustments aren't relevent as the distance is no where near long enough so the white space can be trimed

Is it using TDMA maybe CDMA?
what kind of modulation is it using?
I hope its not using CSMA/CD although CSMA/CD is used with ethernet its irrelivent due to full duplex and switches


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## veryoldschool (Dec 10, 2006)

Well you seems to have "splattered" every aspect here without having too much to do with a signal in coax.
Several/many posts back I listed what is known, which is limited to frequency, bandwidth, & bit-rate.
The modulation used isn't known [by me at least].
How the signal propagates through the system, is known fairly well by me, as I was in the test group, and have spent over 35 years working with various RF systems.


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## DarkLogix (Oct 21, 2011)

well I normally don't think about poloization due to thinking about docsis mostly, in which the they're using them all at the same time such that its near impossible to use many methods so instead they use docsis constellations to simplify the data

so as you don't know the fine details you can't be sure that its not one big collision domain just with a large amount of bandwidth

saying that the "cloud" has over 250mbps and throughput make it sould that its shared bandwidth and in the same fashion a 8 port 100mbps switch has 1600mbps of throughput which means that its a step down from ethernet


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> well I normally don't think about poloization due to thinking about docsis mostly, in which the they're using them all at the same time such that its near impossible to use many methods so instead they use docsis constellations to simplify the data
> 
> so as you don't know the fine details you can't be sure that its not one big collision domain just with a large amount of bandwidth
> 
> saying that the "cloud" has over 250mbps and throughput make it sould that its shared bandwidth and in the same fashion a 8 port 100mbps switch has 1600mbps of throughput which means that its a step down from ethernet


In the RF domain there aren't collisions, but in the networking world there are, which is why it's hard to talk RF to a network person as they have a mindset that doesn't crossover well, just as an RF person has a mindset that also doesn't crossover well.
I too can find a bad connector in an ethernet cable, but it doesn't make me a network person either. 
I tend to "plug and play", where I plug it in and "play" until I get it to do what I want. :lol:


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## DarkLogix (Oct 21, 2011)

Docsis is RF on coax just a differant scale and set of modulations
in ethernet a collision is when the same lines sending recive something
if you had say two RF signals talk at the same exact modulation at the same time what happens?

I know with Wifi they cause a collision at the AP's radio

in ethernet collisions don't happen anymore so long as you're using a switch not a hub and you're in full duplex mode, so claiming that Deca avoids collisions is false as there weren't any to avoid

if collisions weren't possible then lets all go back to tokenring over RF on coax like the old days where only one computer was permited to transmit at a time.

Please provide details as to collisions not being possible


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## DarkLogix (Oct 21, 2011)

I'm goin to bed 
Back hurting but not tired is a very annoing state to be in


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## GregAmy (Jan 7, 2008)

DarkLogix said:


> so I don't seewhy deca would be better than just eth as its going to eth to reach teh deca.


I'm inferring that DECA is faster than 100Mbit? There is an annoying delay now when I'm trying to watch a program from another receiver, notably when it starts and when I try to fast forward. Just not as snappy.

For my specific situation, another advantage is that the DECA removes the need for running CAT5 up to that last (and any future) receiver.



> and if you use a switch not a hub then its not going to slow the network...


Good point. In my case, most of our traffic is not necessarily intra-network, but from clients to/from Internet, which is 3(?)MBit. So I'm guessing clients won't really notice the difference.

But you're right: it is smarter to keep the inter-receiver traffic on its own switch.

GA


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> Docsis is...


While it and Wifi both use RF, they're not the same as DECA, which is DirecTV's version of MoCa.

Perhaps there is more here for you: http://www.mocalliance.org/marketing/whitepapers.php [especially PQoS - Parameterized Quality of Service]

*http://www.mocalliance.org/marketing/white_papers/PQoS_White_Paper.pdf*


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## DarkLogix (Oct 21, 2011)

GregAmy said:


> I'm inferring that DECA is faster than 100Mbit? There is an annoying delay now when I'm trying to watch a program from another receiver, notably when it starts and when I try to fast forward. Just not as snappy.
> 
> For my specific situation, another advantage is that the DECA removes the need for running CAT5 up to that last (and any future) receiver.
> 
> ...


I would hope that a 3mbit link would be via a router, so unless theres a default gateway pointing it to the 3mbit link it shouldn't use it

Yes I see that Deca offers the advantave of fewer wires which is the reason that I might make use of it at some point

with a ethernet switch if device1 sends data to device2 then only 1 and 2 are talking and its not going to send that data out everyport (if you had a hub then it would)

the only use for a hub these days is for traffic sniffing as with software link wireshark you can't sniff data over a switch because the data is only going 1 to 2 not to 3


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## harsh (Jun 15, 2003)

veryoldschool said:


> In the RF domain there aren't collisions, but in the networking world there are, which is why it's hard to talk RF to a network person as they have a mindset that doesn't crossover well, just as an RF person has a mindset that also doesn't crossover well.


In the RF domain, they call the problem of two sources trying to use the same medium "interference" and it isn't an easy problem to solve.

MoCA trys to take a more preemptive approach based on a common timebase and fixed communications windows but there will still be many opportunities for contention that must be dealt with.


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## veryoldschool (Dec 10, 2006)

harsh said:


> In the RF domain, they call the problem of two sources trying to use the same medium "interference" and it isn't an easy problem to solve.


Which may be more commonly called "signal to noise ratio", which the cLink LED will indicate when there is a problem.


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## DarkLogix (Oct 21, 2011)

harsh said:


> In the RF domain, they call the problem of two sources trying to use the same medium "interference" and it isn't an easy problem to solve.
> 
> MoCA trys to take a more preemptive approach based on a common timebase and fixed communications windows but there will still be many opportunities for contention that must be dealt with.


Thanks that fills in some of the details

so they all sync up to a common timebase and use timeslices ie a form of TDMA

that explains how MoCA handels it as each device only gets a window to send in

Thanks for posting some of the info I had been looking for now do you know if Deca does the same?


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## RunnerFL (Jan 5, 2006)

DarkLogix said:


> Thanks that fills in some of the details
> 
> so they all sync up to a common timebase and use timeslices ie a form of TDMA
> 
> ...


DECA IS MoCA.


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## DarkLogix (Oct 21, 2011)

RunnerFL said:


> DECA IS MoCA.


I knew its the same idea is it fully the same specs? ie interchangable?


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> I knew its the same idea is it fully the same specs? ie interchangable?


No, it's DirecTV's version [as they are part of the alliance].
MoCA comes in many "flavors", and DirecTV uses the 550 MHz CF, which the others don't.


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## DarkLogix (Oct 21, 2011)

veryoldschool said:


> No, it's DirecTV's version [as they are part of the alliance].
> MoCA comes in many "flavors", and DirecTV uses the 550 MHz CF, which the others don't.


Ok so other than the frenquency is it the same and if not how so?
you've said you don't have further details so I think at some point I'll have to buy one and open it up and look up the partnumbers of the chips


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## veryoldschool (Dec 10, 2006)

DarkLogix said:


> Ok so other than the frenquency is it the same and if not how so?
> you've said you don't have further details so I think at some point I'll have to buy one and open it up and look up the partnumbers of the chips


While I know you want to know more, what you want would need to come from DirecTV, as it's there version.


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## DarkLogix (Oct 21, 2011)

veryoldschool said:


> While I know you want to know more, what you want would need to come from DirecTV, as it's there version.


Ya
and I doubt I'll get the R&D dept on the phone to ask about the details
but from opening one and looking up the chip part numbers I can gain some insight into it, maybe not as much as I want but more than I have.


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## harsh (Jun 15, 2003)

veryoldschool said:


> Which may be more commonly called "signal to noise ratio", which the cLink LED will indicate when there is a problem.


To the client who wants to get out, it isn't noise. It is someone else keying at the same time.


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## veryoldschool (Dec 10, 2006)

harsh said:


> To the client who wants to get out, it isn't noise. It is someone else keying at the same time.


Since this is a DirecTV thread, "once again" your post/reply is meaningless.


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## harsh (Jun 15, 2003)

veryoldschool said:


> Since this is a DirecTV thread, "once again" your post/reply is meaningless.


So it isn't possible that two clients can request service at the same instant in the window set aside for transmission of remote commands?


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## veryoldschool (Dec 10, 2006)

harsh said:


> So it isn't possible that two clients can request service at the same instant in the window set aside for transmission of remote commands?


 How the #$^* does a remote have anything to do with a networking topic here?
[oh never mind, it's just another ridiculous post from you]


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## DarkLogix (Oct 21, 2011)

veryoldschool said:


> How the #$^* does a remote have anything to do with a networking topic here?
> [oh never mind, it's just another ridiculous post from you]


well based on the context I don't think he's referring to a TV remote but using remote in the sense of local v remote.

i.e. a remote device is a device that is not in front of you and a device that's in front of you is the local device

so applying those contextual bits of info he's saying a device in room A and a device in room B sending data on the common coax at the same time.

However IF what he claimed earlier is accurate then it would prevent this


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## harsh (Jun 15, 2003)

veryoldschool said:


> How the #$^* does a remote have anything to do with a networking topic here?


Remote control commands from a WHDS client are not nearly as predictable as video streams yet they must share the same bandwidth. It has absolutely everything to do with DIRECTV and DECA.

On the other hand, it wouldn't apply in a switched Ethernet scenario.


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## veryoldschool (Dec 10, 2006)

harsh said:


> Remote control commands from a WHDS client are not nearly as predictable as video streams yet they must share the same bandwidth. It has absolutely everything to do with DIRECTV and DECA.
> 
> On the other hand, it wouldn't apply in a switched Ethernet scenario.


Garbage


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## harsh (Jun 15, 2003)

veryoldschool said:


> Garbage


WHDS over DECA transmits remote control commands from client to server using magic?


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## veryoldschool (Dec 10, 2006)

harsh said:


> WHDS over DECA transmits remote control commands from client to server using magic?


I have absolutely no #$%*ing idea of what you're talking about.
The remotes I have only send commands to the receiver their coded to.
Any "commands" over the network from WHDS clients, would be the same commands be it DECA or ethernet.
If you're somewhere way the hell out there, asking about any DECA network management commands, as nobody knows how it's being done, there is no reason to think that these would impact the data, as they could be on their own frequency. There is so much potential bandwidth with a clock of 550 MHz and the 50 Mhz bandwidth.
We're only using MoCA 1.1, and 2.0 looks much faster:
http://www.mocalliance.org/MoCA_2/index.php


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## veryoldschool (Dec 10, 2006)

harsh said:


> [garbage]


You have always been in favor of ethernet over RF networking.
1 gigabit ethernet, duplexed "at best" could carry 2 Gb/s data.
50 MHz to 1 GHz of RF [or 950 MHz of bandwidth], using the ATSC model, could carry 3 Gb/s.


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## harsh (Jun 15, 2003)

DECA doesn't use 9,950MHz of bandwidth. It has an effective maximum transfer rate of 175Mbps (regardless of center frequency) and is half duplex.

Somewhere in the time division there is an interval set up for clients to make requests of their respective servers. Unless each client has its own interval, there is a possibility that two clients will ask for an interval at the same instant. It would seem that simultaneous requests would be lost to interference. This is the same way collisions were experienced and handled before switching (ignoring token passing schemes).

Switched Ethernet doesn't lose packets even if they do come in simultaneously.

I get it; DECA is something that doesn't require an additional low voltage license to install. That's good for the pay TV and broadband providers. I'm not conditioned to believe that what's best for the provider is necessarily ideal for me.

I believe that at some point in the not-too-distant future, RF will no longer be part of most people's entertainment experience. Media of all kinds will be carried over IP connections to devices large and small. I see IP over coax as being an interim step (kind of like HomePlug was in the early days of "cinema connection kits".


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## veryoldschool (Dec 10, 2006)

And "the garbage" continues :nono:

Let us know when your provider offers anything like DECA and you have any first hand experience with it.


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## GregAmy (Jan 7, 2008)

"Project SWM/DECA Conversion" is a success. I'd like to thank everyone in this thread for their assistance (despite the entertaining side conversations...).

I ended up going with the SMW8 and splitter version; it was cheaper and helluva lot less work. The hard part was just finding mounting spots for all the components and a power strip. For the DECA part I bought three DECA off eBay for my receivers, and one of those wired "routers" (or is it a bridge?) to connect between my splitter and home network. All went in fine, I didn't even have to change my existing static IPs in the receivers. It was kinda disappointing, though, being able to get rid of two B-Band Converters but having to put a DECA back on (anyone want to buy 6 BBCs?) I'll look into replacing my receivers with 24s or something like that; I'm thinking of just going with a H25/C30(?) for the garage, anyway, especially if I can get a HR34.

Kinda impressed about how hot the components are running, especially the SWM8; even the DECA are getting warm. I'm wondering how much more electricity I'll be using with this setup...

Got a couple questions:

- DECA works fine without having called DTV. Other than getting blessed as "supported", why would I want to call them and deal with possibly getting rejected? Where's the value? Can't I just play dumb if there's a problem and tell them at that time the DECA was already installed and working fine?

- PokerJoker on page 1 noted "Use only compression-type RG6 fittings (preferably PPC EX6XL), never use crimp or twist-on!" I went with crimp fittings because that's all the tools and fittings I have, and it seems to work fine. I'll look into getting a good tool and materials for making compression fittings going forward, but what's the disadvantage of going with crimp-type?

Thanks, all! - GA


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