# Can I diplex OTA?



## Kansas Zephyr (Jun 30, 2007)

I hope this is the right forum.

I'm not a Dish customer. But, my in-laws are, and they need my help.

They have the latest non-DVR HD receiver. I don't know the model number.

They need an outdoor antenna to get their locals in HD (very small market).

Can I diplex the OTA feed into the existing single cable run?

Thanks.


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## James Long (Apr 17, 2003)

Yes, you can.

Make sure that you use diplexers designed for satellite with frequency ranges up to 2175 MHz on the satellite side and DC blocked on the antenna side. You will place one diplexer where you want to combine the signals and another diplexer where you want to split them. NOTHING but coax should be between the two diplexers (no switches, splitters, combiners, etc.).


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## Kansas Zephyr (Jun 30, 2007)

Thanks


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## Cap'n Preshoot (Jul 16, 2006)

James Long said:


> Yes, you can.
> 
> Make sure that you use diplexers designed for satellite with frequency ranges up to 2175 MHz on the satellite side and DC blocked on the antenna side. You will place one diplexer where you want to combine the signals and another diplexer where you want to split them. NOTHING but coax should be between the two diplexers (no switches, splitters, combiners, etc.).


I'm doing it -without- additional diplexers, meaning no more than what's already there (assuming you're already hooked-up to back-feed a 2nd room TV from your 222) I'm also using only conventional CATV (not high freq.) splitters but am using DC-blocking just as a precaution (hooked up the way we are it's not required). 2150-Mhz rated splitters might technically be better, but a good quality (soldered-back, not press-fit & glued back) ordinary CATV splitter works fine.

See related thread in the general discussion forum.


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## Jason Nipp (Jun 10, 2004)

You really should use a Dish Pro Plus approved Di-Plexor if you are running a "DPP Twin" or "DPP44 switch", and yes it is highly recommended that the Di-Plexor should be rated good for 2175MHz, just as it is recommended to be at least 2175MHz for any other Dishnetwork LNBF or switch gear.

While it is possible to use basic 900MHz CATV Di-Plexors (Not Splitter),it is not recommended by Dish Network nor most of the veterans and industry professionals in this forum. But since the user said "non-DVR HR" I do not know what DirecTV recommends.

But back to Dishnetwork since that is the forum you are in....


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## Cap'n Preshoot (Jul 16, 2006)

Jason Nipp said:


> You really should use a Dish Pro Plus approved Di-Plexor if you are running a "DPP Twin" or "DPP44 switch", and yes it is highly recommended that the Di-Plexor should be rated good for 2175MHz, just as it is recommended to be at least 2175MHz for any other Dishnetwork LNBF or switch gear.
> 
> While it is possible to use basic 900MHz CATV Di-Plexors (Not Splitter),it is not recommended by Dish Network nor most of the veterans and industry professionals in this forum. But since the user said "non-DVR HR" I do not know what DirecTV recommends.
> 
> But back to Dishnetwork since that is the forum you are in....


No offense meant, but there's more than one way to skin this cat. Think outside the box. In the method I propose two ordinary splitters is all that's required. Please understand that we're opening up the coax between the furnished diplexor uhf/vhf output leg and the output jack for the 2nd room TV feed on the back of the receiver (STB), ergo there is no L-band signal here (and no DC). A common household CATV splitter is absolutely all you need here. There is no frequency component above 900 Mhz where we're breaking the circuit and inserting our splitter.

At the other end (attic or wherever) we effectively 'mix' our OTA signal into the drop cable that's headed toward the 2nd Room TV (again downstream of the again furnished) diplexor, hence here too a common 2-way splitter is all that's needed. Don't let the in/out markings on the splitter intimidate you. Hook one of the "outs" to the 2nd room output of the STB. Hook the other "out" leg to the input jack for the "antenna" and connect the input leg to the coax coming from the uhf/vhf port of the provided diplexor. In the attic do the same thing. Connect the output legs of the splitter one to the uhf/vhf port of the furnished diplexor and the other to the coax headed into the "2nd room" - connect the input leg to your OTA antenna.

Your OTA signal will encounter some loss (approx 8~10 db) in this jerry-rigged configuration but it will make it back around the horn and back down the primary (L-Band) coax feed to the STB where we split (after the furnished diplexor) and connect to the OTA jack of the STB.

You may encounter some unwanted back radiation of channel 62 (or whatever you use for the 2nd room) from your OTA antenna but there's a simple way to solve that too. Just install a uni-directional (cheap) amplifier.

components needed:
 two std 2-way CATV splitters
 four short coax jumper cables 8~10" each
 optional: amplifier

Give it a whirl. Bet you'll find it works.


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## Jason Nipp (Jun 10, 2004)

Never said that it wouldn't work, just that it's not recommended. 

I have to ask, why go through the trouble if you can find a set of cheap diplexors for less than $10?


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## CABill (Mar 20, 2005)

Jason Nipp said:


> I have to ask, why go through the trouble if you can find a set of cheap diplexors for less than $10?


I'd go back to your original comment about DISH approved diplexors. I don't see anything in the OP to indicate the in-laws have any existing diplexor to start with. If they do, it would likely be an approved one. If they don't, and have a DPP switch, the current used will wipe out many diplexors that aren't approved. A Holland DPD2 can be obtained very cheaply on eBay but there are other approved units and routes to get them.


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## Cap'n Preshoot (Jul 16, 2006)

CABill said:


> I'd go back to your original comment about DISH approved diplexors. I don't see anything in the OP to indicate the in-laws have any existing diplexor to start with. If they do, it would likely be an approved one. If they don't, and have a DPP switch, the current used will wipe out many diplexors that aren't approved. A Holland DPD2 can be obtained very cheaply on eBay but there are other approved units and routes to get them.


And my alternate method obviates any need for any hassle with finding additional diplexors or concern about getting the right ones. I tend to gravitate to the KISS method when presented w/choices. If you're using a 222 (or 622/722) and backfeeding a 2nd room then all the diplexing is already done for you. Stay out of the hot (powered) leg. Push your OTA sigs into the 2nd set circuit (vhf/uhf leg off the existing diplexor) and it will find its way back to the STB just fine. In cases where the attenuation is too great then amp your OTA by 10 db. You will not bother your L-Band (sat) feed (he won't even know you're there) and you won't short-out your LNB control voltage because he won't see you in the circuit either.

No it may not be an approved method, but it works, it's simple and does not conflict with control signals or add any attenuation in the L-Band signal path


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## Kansas Zephyr (Jun 30, 2007)

OK...I'm a Dish noob. Since, I'm a D* customer.

They have two dishes into a single cable run. That feeds a Dish non-DVR HD receiver (VIP 211...I think), which is feeding a single HDTV via HDMI.

So there is no back-fed MRV.

If that helps, thanks.


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## CABill (Mar 20, 2005)

DirecTV HD will prevent diplexing on the sat cable with some of their LNBs, but DISH doesn't go below 950MHz. The single coax feed carries 950-1450MHz and 1550-2150MHz. That's JL's reply #2 to be sure the diplexer you get would cover the 2nd 500 MHz band. If you hit Menu-6-1-3, you should see what type of switch you use in "Device". If it says DP21, you might have a DP Twin on the 500 and DP dual on the side dish and then the current wouldn't be an issue. If it says DPP (DP Plus) Twin is where you need to be sure the diplexer is "approved". I don't know what is on the list, but have a DPD2 sitting here at the desk and know it is. Search for that and you should find others that can handle the current of a DPP switch.

Before doing that, you might try just using a length of coax to some indoor antenna by a window just to see what they get w/o diplexing an antenna in on the sat coax. www.tvfool.com and www.antennaweb.org would give info on whether they would need an outside antenna.

I don't have any experience with the Silver Sensor, but peek at http://www.hdtvprimer.com/ANTENNAS/silver.html if inclined.


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## Kansas Zephyr (Jun 30, 2007)

CABill said:


> Before doing that, you might try just using a length of coax to some indoor antenna by a window just to see what they get w/o diplexing an antenna in on the sat coax.


Been there done that.

They are 40+ miles from Abilene, and 40+ from San Angelo, TX. They only get two stations, with frequent dropouts, using a good set of ears/loop with a 50dB preamp.

They need a CM4228 on a rotator to get everything "close by" solid.


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## Cap'n Preshoot (Jul 16, 2006)

Kansas Zephyr said:


> Been there done that.
> 
> They are 40+ miles from Abilene, and 40+ from San Angelo, TX. They only get two stations, with frequent dropouts, using a good set of ears/loop with a 50dB preamp.
> 
> They need a CM4228 on a rotator to get everything "close by" solid.


Ouch! Yes, in this situation, assuming you want to stay with one coax cable, you're going to need two diplexors and DC-blocking. (some 300~75-ohm baluns have DC-blocking built in) DC blocking adapters are about $2 from places like techtoolsupply dot com

The situation I was describing was for someone with a 222/722 (622) and backfeeding a 2nd room from 1 common set top box (STB)

The 4228 is a good product, albeit fairly heavy (made of steel instead of aluminum). I saw an article recently suggesting you physically tie the two rear grids together so they form an electrical bond with one another. If ty-wraps, be sure to use black ones. White will become brittle from the sun and eventually break off.


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## Cap'n Preshoot (Jul 16, 2006)

CABill said:


> DirecTV HD will prevent diplexing on the sat cable with some of their LNBs, but DISH doesn't go below 950MHz. The single coax feed carries 950-1450MHz and 1550-2150MHz. That's JL's reply #2 to be sure the diplexer you get would cover the 2nd 500 MHz band. If you hit Menu-6-1-3, you should see what type of switch you use in "Device". If it says DP21, you might have a DP Twin on the 500 and DP dual on the side dish and then the current wouldn't be an issue. If it says DPP (DP Plus) Twin is where you need to be sure the diplexer is "approved". I don't know what is on the list, but have a DPD2 sitting here at the desk and know it is. Search for that and you should find others that can handle the current of a DPP switch.
> 
> Before doing that, you might try just using a length of coax to some indoor antenna by a window just to see what they get w/o diplexing an antenna in on the sat coax. www.tvfool.com and www.antennaweb.org would give info on whether they would need an outside antenna.
> 
> I don't have any experience with the Silver Sensor, but peek at http://www.hdtvprimer.com/ANTENNAS/silver.html if inclined.


D*'s latest equipment, their rain fade-prone Ka birds for HD and their disappointing limitations for OTA (not supported at all) and complete removal of an ATSC tuner from their newest STBs is exactly why I'm an E* subscriber today.

The Silver Sensor is a swell indoor antenna if you're within 20~25 miles of the station. Shame they don't make it in a ruggedized outdoor mast-mount version.

I agree with CABill, for the amount of hassle you're going to have to go through I'd want to make some tests with a length of coax straight from the OTA antenna jack to a directional antenna stuck out the window & pointed in the general direction of one of the stations of interest.


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## puckwithahalo (Sep 3, 2007)

short answer to your question, yes, it can be diplexed, just make sure that the diplexors are rated for satellite (2175 MHz) and dc blocked on the antenna side if the lnb or switch is DPP (menu, 6,1,3 and check box H for device), if not DPP, DC blocked is not necessary i think.

The rest of the discussions going on are relevant if you already had diplexors in for a backfed tv2, but since you don't, that's all you really need to know


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