Yuri wrote:
You guys might try to poke fun at this. But there are many factors
contributing to signal levels received at the other end. Antenna
pattern, local ground conditions, terrain and propagation conditions.
VHFers know about ducting on VHF between W6 and KH6, you drive up the
hill and you can find spot where your signal (few watts) will hit it
and you QSO with KH6. You go few hundred feet up or down and you lose it.
Sure, all of that is true... but it all goes strictly dB for dB. There
is no support for tropo ducts behaving in a non-linear fashion.
Let's not confuse the variable *importance* of a dB under different
circumstances (which is obviously true) with any suggestion that the
propagation medium itself is non-linear.
A non-linear medium would have to mean that your signal was directly
affecting the ionization density or the refractive index of the
troposphere. As I already said, that's wishful thinking at amateur power
levels.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
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