# Does OTA Antenna/Diplexer impact signal quality?



## cliffbig (Jan 17, 2005)

If this has been discussed, I'm not finding it: can anyone tell me if using an external antenna and a diplexer to merge the signal and bring it in through the DirecTV cable run will negatively impact my satellite dish or antenna signal at all? I don't currently have an external antenna, but am considering adding one; however, I didn't want to have to run separate antenna feeds to the different receivers scattered throughout the house. One friend had said that he thought that diplexing the signal through the DirecTV cable would lower my signal quality and increase macroblocking and pixellation on DirecTV. Anyone know if that's true?

cliff biggers


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## dogdoctor (Feb 20, 2006)

cliffbig said:


> One friend had said that he thought that diplexing the signal through the DirecTV cable would lower my signal quality and increase macroblocking and pixellation on DirecTV. Anyone know if that's true?


I will be upfront and say that I am no technician and the following only comes from personal experience.

I found that the diplexors used in my set up were crap - satellite signal was fine but I lost an entire channel of OTA due to increased signal loss thru the diplexors. Removing the diplexors and running the antenna straight the the HR10 gave me all the OTA channel without problems. I think in most cases the satellite feed will be fine, as for the OTA it will likely depend upon the relative originating channel signal strength, the "strength" of the antenna on your house (something with gain/amps ect...), the quality of the diplexors, and the length of cable run to your STB. The cleanest signal of OTA will likely come from a direct feed, but other have posted success with diplexors. In my case it was bad diplexors that caused the loss/reduction of signal for ABC and I simply chose not to replace them, but to remove them.

Also check D* Tivo Forum Thread: http://www.tivocommunity.com/tivo-vb/showthread.php?t=296747


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## Dssturbo1 (Feb 23, 2005)

what the dog said........
try it diplexed and if problems do a straight run for the ota.


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## Sir_winealot (Nov 18, 2000)

IIRC I've read here that there is a possible loss of up to -2db (someone will correct me if I'm wrong) whilest utilizing a diplexer...sometimes enough to impact your signal, sometimes not.

I've got one setup with all OTA channels coming in between 79-90 (direct cable run from antenna), and I'll soon be hooking up a 2nd. Unfortunately for me I cannot do the 2nd wall drop so I've just purchased a couple Eagle Aspen diplexers off Ebay ($12 incl shipping) and will be putting them to the test.

Hopefully all channels will come in w/o problem....


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## the_bode (Aug 10, 2005)

I bought a cheap Radio Shack in-line powered signal amplifier, and it mitigated the signal loss via the diplexer.


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## TyroneShoes (Sep 6, 2004)

cliffbig said:


> ...can anyone tell me if using an external antenna and a diplexer to merge the signal and bring it in through the DirecTV cable run will negatively impact my satellite dish or antenna signal at all?...One friend had said that he thought that diplexing the signal through the DirecTV cable would lower my signal quality and increase macroblocking and pixellation on DirecTV. Anyone know if that's true?
> 
> cliff biggers


Adding a diplexor does two things that can be considered negative in their impact (it is a compromise to share a downlead, after all). It will increase the amount of reflected signal in the downlead (higher VSWR) which can lower the signal and make it harder to lock, and it will lower the signal level directly on some frequencies due to the filtering. It may be negligible, or it may be enough to make a difference. It will affect continued signal reception _integrity_, but can have no affect on picture quality when the picture is actually locked.

Try a different (better) set of diplexors, or abandon them in favor of a home run. If this is an initial setup, having diplexor issues will just confuse the reception/tuning issue, so I would try a temp home run at least until the antenna system is set up properly.


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