On 2/11/20 11:30 AM, Jim Brown wrote:
On 2/10/2020 8:41 PM, Grant Saviers wrote:
I think 4sq vs 2L beam tradeoff depends on the beam height vs ground
conductivity and thus the 4sq gain/pattern.
Yes. Several years ago, I did a modeling study of horizontal and
vertical antennas vs height and ground conductivity. It's here.
http://k9yc.com/Multi-Station.pdf
N6BT (original Force 12 designer/owner) recently published the results
of a ground-breaking study he did of verticals and terrain. Tom is a
very smart engineer.
https://ncjweb.com/features/mayjun19feat.pdf
I wonder what you'd get if you modeled the vertical as slanted (relative
to vertical) using NEC, as if you had a vertical antenna on a sloping
surface.
You're not going to be able to model things like a cliff, or a slope
down to the beach with NEC, but a 12 degree downslope should be modelable.
I think a lot of the handwaving about vertical pol and models is because
for H-pol, the ground is pretty much a mirror and the incidence angle
isn't super important, nor is the precise soil properties. But for a
V-pol it really depends, and it's highly angle dependent. That's what
Dean N6BV says is why HFTA is Hpol only - it was too complex to add in
the Vpol calculations.
I suspect that these days, one could build an equivalent of HFTA that
handles both pols and a terrain model (such as that for RadioMobile for
VHF and up). However, you're still stuck with the significant
variability in soil properties.
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