[TowerTalk] Vertical question

[john at kk9a.com]

I assume that you need NEC4 to accurately model a vertical and elevated
radials. The original poster was using a program called Antenna Model which
I never heard of.

John KK9A

Jim Lux wrote:

It's probably more that the soil dielectric properties far from the 
antenna have a significant effect on vertical polarized propagation, 
while for horizontal polarization, the soil is basically a mirror, 
regardless of the dielectric properties. This is one reason that HFTA is 
for H-pol antennas - it's easier to compute.

The modeling tool will tell you the amplitude of the "launched wave" and 
will factor in the loss in the soil directly under the antenna, which is 
greatly reduced by radials.  But it *might not* factor in the effect of 
the soil hundreds of meters away, or, the soil there might have 
different dielectric properties than the soil you used in your model.