[TowerTalk] vertical distance

[Jim Brown]

On 8/15/2022 9:39 PM, w5jmw at towerfarm.net wrote:
> The dxe 75/80 meter verticals and the phasing box.I have entertained 
> thoughts on selling.No one wants to come and pick them up.SO.I am going 
> to put them up.They will be in somewhat of a line with my 55ft 
> tower.What is a safe distance? By that what distance so the 55ft tower/w 
> beams.wont see the verticals? 1/4 wave is easy.1/2 wave may be a 
> problem...what do you say??

All those vertical conductors WILL see each other. There are no "safe" 
distances. HOW they interact will depend strongly on their layout and 
heights. This is a system that demands a simple NEC model that includes 
all of them, including any others you may be overlooking, like the 
feedlines for horizontal antennas. My 120 ft tower is 210 ft N of my 100 
ft Tee vertical for 160M, and it acts as a reflector, with a bump of 
about 2-3 dB to the south with a matching dip to the north.

My only verticals are for 160M, because I'm in a dense redwood forest, 
and the trees suck up vertically polarized RF much more than 
horizontally polarized RF. I have resonant coax-fed dipoles for 80, 40, 
and 30, each with a serious choke at the feedpoint and an additional 
choke fairly close to the ground to act like an "egg insulator" to break 
up the feedline so that it doesn't interact with the 160 antennas.

Here's all it takes to build a serious choke.
http://k9yc.com/2018Cookbook.pdf

73, Jim K9YC