Topband: ground wave & vertical polarization

[Al Williams]

> On the other hand, vertically polarized signals are re-enforced by 
> the earth. Antennas near earth "want" to hear vertical signals, 
> because the earth tends to re-enforce vertically polarized signals 
> and cancel horizontally polarized signals.
> 
> Actually, this is also the very reason ground wave propagation 
> must be vertically polarized, and why the noise that propagates 
> along the earth for a distance is all vertically polarized.
 
I overheard a ham on 75 fone allow as the reason his signal
was not very strong was because of ground wave attenuation.

We could use a few words on the relationship (for more or
less local (i.e. up to perhaps 50/75 miles or so) of signal strengths
for NVIS horizontal antennas, vertical antennas, and ground wave
propagation--at 75 meters.

thanks

k7puc