Diplexers - opinions?

hancox

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Nov 23, 2003
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All of the V* guys seem to be vehemently anti-diplexer, saying it comes with a sharp decline in signal strength to the OTA side.


Most E* guys seem to be ok with a diplexer.


Is this bad equipment on the V* side? Any of you diplexers care to comment?
 

DarrellP

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Nov 6, 2003
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This is BS. I've been using a diplexer with my home theater for about 3 years now and I've tested the PQ with/without the diplexer in place and see NO degradation in PQ. I am vieiwing on a 110" screen with a front projector and believe me, if there is the slightest issue with PQ, I notice it.

You do need to buy a good quality unit though, not the $5 jobbies at Rat Shack. I payed $28 for the pair I have.
 

bpasker8

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Dec 20, 2003
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I'm installing my diplexers and OTA rooftop antenna tonight into my dish 811 so I'll let ya'll know how it works. I bought two Eagle Aspen diplexers off ebay for about $10 a pair. MHZ says 950-2250/40-806 on it so sure hope it works out for me...
 

cdru

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DarrellP said:
You do need to buy a good quality unit though, not the $5 jobbies at Rat Shack. I payed $28 for the pair I have.
I found the opposite was true...or at least it was for the pair I purchased. I got a pair from Lowes for about $30 I beleive. They weren't nearly as good as the $10 pair I got from a sat installer. And BTW, you won't find a $5 diplexer at Rat Shack. The cheapest they have now-a-days is $20 for an RCA diplexer.
 

hancox

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DarrellP said:
This is BS. I've been using a diplexer with my home theater for about 3 years now and I've tested the PQ with/without the diplexer in place and see NO degradation in PQ. I am vieiwing on a 110" screen with a front projector and believe me, if there is the slightest issue with PQ, I notice it.

You do need to buy a good quality unit though, not the $5 jobbies at Rat Shack. I payed $28 for the pair I have.



PQ wouldn't be the problem. I would be interested if your signal meters look any different.
 

hancox

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rang1995 said:
maybe it's the combo of the diplexer and a certain model STB that causes problems?


that's what I'm trying to get at. Maybe the Voom STB/switch sucks. Maybe the E* one is just as bad. Just looking to avoid drilling another hole if I don't have to
 

bpasker8

SatelliteGuys Family
Dec 20, 2003
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I installed my diplexers last night and am currently running them with my rooftop antenna and dish 500 into my 811. No issues at all, ota channels are great and no sacrifice in pq for either... I'd have to say I'm comletely satisfied with the set up...

One other thing... rang1995... that is THE best damn avitair I've ever seen! I need me one of them, and not the avitair!
 

chastulsa

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Dec 4, 2003
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Just a FYI,


You cant suffer PQ on a digital feed. Its either 100% quality or 0%. You may suffer signal loss in which you may not receive the signal at a strong enough level to be displayed through the receiver.
 

wickedtao

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Dec 16, 2003
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bpasker8 said:
I'm installing my diplexers and OTA rooftop antenna tonight into my dish 811 so I'll let ya'll know how it works. I bought two Eagle Aspen diplexers off ebay for about $10 a pair. MHZ says 950-2250/40-806 on it so sure hope it works out for me...


the diplexors you meantioned are fine unless you have cable interent. cable internet sometimes uploads frequencies around 0-40 mhz, depending on the MSO.
 

Broadband Lab Rat

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Nov 10, 2003
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Alabama
Laws of physics shall apply...

Adding a passive diplexer in the line will ALWAYS add additional loss on both the OTA signals and on the satellite signals. The real question is will your paticular installation of antennas, transmission lines and receivers be negatively affected by the additional loss.

If one of your receivers, channels, etc. is near the edge of not working due to a weak signal, then adding a diplexer may well be the straw that breaks the camel's back.

If you have plenty of signal margin, then the added loss will not matter.

FWIW, adding diplexers also adds several additional points of potential connector and component failure into the mix as well.
 

ocaddict

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Jan 5, 2004
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Atlanta
I'm using diplexers that were supplied with my TERK TV42 antenna. I can't pickup even 1 OTA channel. Doubt it's the diplexers fault hower as this antenna seems to be a real POS. Packing it up to return to circuit city here real soon. I'd love to get something like the UHF 15-2160 mentioned earlier, but living in an apartment really limits my choices for OTA antenna's. O'well.
 

rang1995

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Sep 30, 2003
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sounds like what i am getting..

Adding a passive diplexer in the line will ALWAYS add additional loss on both the OTA signals and on the satellite signals. The real question is will your paticular installation of antennas, transmission lines and receivers be negatively affected by the additional loss.

If one of your receivers, channels, etc. is near the edge of not working due to a weak signal, then adding a diplexer may well be the straw that breaks the camel's back.

If you have plenty of signal margin, then the added loss will not matter.

FWIW, adding diplexers also adds several additional points of potential connector and component failure into the mix as well.
 

hancox

Pub Member / UConnaholic
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Nov 23, 2003
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Broadband Lab Rat said:
Adding a passive diplexer in the line will ALWAYS add additional loss on both the OTA signals and on the satellite signals.


OK - now it sounds like we're getting somewhere. :)

Do "active" diplexers exist - I guess these would be the equivalent of active (amplifying) cable splitters?
 

Broadband Lab Rat

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Nov 10, 2003
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Alabama
Good question...!

hancox said:
Do "active" diplexers exist - I guess these would be the equivalent of active (amplifying) cable splitters?
I have never seen such a device where the amplifiers are bundled with the diplexer, but yes... that's the concept.

Assuming that the active amplifier's noise figures are less than the attenuation added by *downstream* diplexers (this would require very expensive, very low-noise amplifiers), then the negative effects of the attenuation added by the diplexers would be negated in the overall system noise figure.

The loss encountered in a diplexer plus it's connectors is typically around 2-3 dB. Most inexpensive signal amplifiers have noise figures of >5 dB. Amplifiers with noise figures less than 2 dB would be required, and are much more esoteric. It would also require amplifiers at the point closest to the signal source in front of both diplexers at each end of the run.

So... yes it could be accomplished in theory, but not practical in cost.. ie, the cost of such devices would far exceed the cost of running separate transmission lines...

Cheers,
 

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