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Re: [TowerTalk] "Magic" length from tower to first insulator

To: towertalk@contesting.com
Subject: Re: [TowerTalk] "Magic" length from tower to first insulator
From: jimlux <jimlux@earthlink.net>
Date: Wed, 16 Mar 2016 11:57:39 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
On 3/16/16 11:39 AM, Larry Loen wrote:
I could imaginably insulate my guys from the tower sections, because I am
using the Rohn brackets to attach them.  I would have to find some suitable
material before the tower went up, but I have time for that if I know what
to select (would want it to be UV resistant if possible, though the bracket
itself will give some sun protection).

I _think_ this helps or at least simplifies the analysis, because it should
take the tower sections themselves out of the picture.  If I understand the
discussion, it would also mean that it restores the tacit assumptions of
the original ARRL paper (albeit without Mr. London's sophisticated
modelling and analysis).

I also wonder if the second set of guys are grounded (which I intend to do
anyway), makes a difference in how the secondary lengths resonate?


The easy way is to do a quick model in NEC.. you're not looking for gnat's eyelash precision.. just "does the pattern or resonance change" (or for that matter, you can do it by looking at the current in the guy segments).


Once you get your model set up, it's easy to change segment lengths, run the sim, and see what it looks like.




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