[TowerTalk] 80 meter antenna advice. (NY6DX)

[jimlux]

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.