Originally Posted by BCF68
Yes Trip I know. It's called "THE GIST". When I say non-directional you know what I mean, so just accept that and move on. No need to get all OCD about it.
If you got it, then I'm not sure why you repeated the same argument over again.
What I told you is that no station has a non-directional antenna pattern, and that even the stations which are noted as being such have variances of 3 dB or more in their patterns. WTVF could, theoretically, have filed this antenna pattern as an omni and you would be none the wiser, except for the fact that it would have an interference issue if it were filed that way.
Or think about it this way, WTVF could have filed the same pattern as WKRN and could have one of their nulls pointed at you, but if it was rotated slightly so that wasn't the case, then one of your neighbors a few miles down the road would be in that null instead of you by virtue of the fact that there is no such thing as a truly omni antenna. Again, you would be none the wiser in that case.
3 dB can make a difference, but usually doesn't. If you have less than a 3 dB margin before the signal stops decoding, your signal is likely too unreliable to depend upon due to atmospheric variations and outside interference sources.
Memphis is 200 miles away from Nashville. So why would there have to be interference protection? I though the limit was 170 miles.
The distance limits were for analog. In digital, there are distance limits on paper, but the actual determining factor is the Longley-Rice interference study. One full-power station cannot create new interference to more than 0.5% of the population of another full-power or Class A station. Even with the directional pattern noted, WPTY receives 0.2711% new interference from the proposed WTVF-25 using the antenna on file. I would assume that an "omni" would increase that above 0.5%.
Well so much for the theory that UHF is better for digital then if low VHF at 22 kW can be 10X more powerful than UHF at 1000 kW.
It's like anything else: a trade-off. I worked at WDBJ during the transition, and I took plenty of calls from people in the mountains who could receive just 7 and 10 over the air in analog, and said that when they scanned in digital, all they could pull in was 15-1 (WBRA-3). That doesn't mean that channel 3 was better in all situations, it meant that for them, channel 3 worked, while UHF stations did not.
In theory, assuming a low-noise environment, outdoor receiving antenna, appropriate amount of power, proper bandwidth, and the stars are in alignment, AM can have better coverage than FM. And yet, the AM band is losing listeners every day. That's because most people don't have low-noise environments or proper outdoor receiving antennas for AM, and many AM stations are not 50 kW and do not have full-bandwidth audio that lets them sound good instead of muddy.