[TowerTalk] Vertical dipole other choices?

[Jim Brown]

On 10/22/2020 8:18 AM, Ron Hill wrote:
> The vertical dipole is about 60' horizontally from the tower so I would
> suspect little interaction.

That's NOT a safe assumption. On the advice of two very smart guys, I 
did NEC modeling to investigate interaction on 160M, and found enough 
interaction to show that my tower gave me more than 2dB of gain to VK/ZL 
using my Tee vertical (with a null to the north), with a separation of 
200 ft. N6LF has published work showing that even relatively short 
towers (and other objects) can cause interaction, both good and bad.

> My ground here is very poor - Sandy gravel down to hard pan at 60' depth.

I have similar conditions here. The only band on which I find verticals 
effective is 160M, and that's because any horizontal antenna I can rig 
is low as a fraction of a wavelength.

73, Jim K9YC