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I installed the RCA ANT751 today. A major factor in that decision was the fact that I could buy it locally and have a more me-friendly option to return if desired. I installed it in the attic, but above and/or on the clear side of all ducts, metal, etc. Only the roof and shingles should be between my antenna and clear air. There is a 50ft run of RG6 between my antenna and the wall outlet, and a ~6ft run of CATV cable (didn't have a short RG6 handy) between the outlet and my TV. I can get all the channels I want (actually 20 in all, including WTZT) except for NBC, Channel 48. I want this channel.
I'm guessing I can't get it due to one of two things, (1) the antenna is not pointed correctly (I have it pointed due East), or (2) noise margin is too low. Probably #2.
Starting Noise Margin = 30.6 dB
Antenna gain = 0 dB est. (can't find it anywhere)
Cable loss = 3 dB per calculation + fudge factor for union and second cable (Should there be more for the outlet and other cable section?)
Building loss = 20 dB est. (help?)
Receiver Noise Figure = 6 dB (estimated because not shown in manual)
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Net residual Noise Margin = 1.6 dB
Now, I think I've answered my own question, so long as all the estimations are reasonable. Clearly a 1.6 margin is unacceptable. Would like an expert verification, though. Perhaps even if I am slightly off, it is still too bad...
Also,
-Does distance between antenna and roofing material matter? I'd be very interested to hear why, if so.
-Would like verification that the slight difference in pointing angle to the NBC antenna is likely not causing a problem here.
Thanks again.
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