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Re: [TowerTalk] More on radials

To: towertalk@contesting.com
Subject: Re: [TowerTalk] More on radials
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 6 Sep 2017 11:00:45 -0700
List-post: <mailto:towertalk@contesting.com>
Hi Rudy,

It certainly is possible to model that tower with all the antennas, at least to a first approximation, if you take the time to do so. It's all XYZ coordinates. The only aluminum that matters is what has a DC connection to the tower, so insulated elements don't need to be modeled.

From your description, I'd say that tower is likely to be resonant below 160M, which would make it an excellent reflector. My sloping radiators are fed about 60 ft from my tower, and need only a bit of inductive loading to resonate them. They are insulated from the tower by a 10 ft piece of 4-in PVC conduit, so their top is about 5 ft from the tower.

You'll need good radial systems to get the gain -- lots of radials for the tower on the ground and at least four on the feedpoint of each of the sloping wires. I have one sloping to about 70 degrees and one to about 270 degrees. I feed them one at a time, with the other shorted. I provide the short in the shack through a suitable length of feedline (close to a half wave).

73, Jim K9YC

On 9/5/2017 6:12 PM, Rudy Bakalov via TowerTalk wrote:
I don't really know. Seriously, the tower itself is 90' BUT there is a KT36XA 
at ~65', then 4 el 40m M2 at 90', and finally another KT36XA at about ~105'. I 
don't think any model can properly factor in all this extra aluminum so I will 
have to actually measure it.


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