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[TowerTalk] Electrically lengthening a boom

To: Towertalk <towertalk@contesting.com>
Subject: [TowerTalk] Electrically lengthening a boom
From: Michael Dinkelman <mwdink@clearwire.net>
Date: Mon, 30 Nov 2009 13:06:39 -0800
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I have a 40M beam underneath a tribander with about 8 feet of 
separation. The tribander is on the mast and
the 40M beam is on a Tic Ring so both can be rotated independently. All 
is well as long as both booms are aligned.
Once the the two start getting a few degrees (~30) out of alignment,  
the SWR on 20M starts rising until I get to
90 degrees (3.3:1) then starts going down again until I reach 180 
degrees. Yes, the boom of the 40M beam is
darn close to resonant  on 20M as it's about 32 feet long. (15M and 10M 
are unaffected)  I've put up with this
for a couple years because I really don't want to bring that 40M monster 
(to me) down.

So, I was investigating detuning the boom (all the elements are isolated 
from it) when I came up with another
possible idea for electrically lengthening it. Why can't I...

1) drill a small hole in the boom
2) insert some stiff wire (or even tubing) inside the boom and push it 
through until it comes out one end
3) electrically connect the wire to the boom where it goes through the hole.

Wouldn't that make my boom longer as far as the 20M elements of the 
tribander
are concerned?  I wouldn't think I would have to go too far out the end 
of the boom.
Even if the wire hangs down a bit off the end that shouldn't be an issue.

Suggestions?

cheers
dink, n7wa


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