You could connect the reflector of the 40m beam to the boom to lengthen it
or you could use Green Heron controllers and keep both antennas in line.
John KK9A
To: Towertalk <towertalk@contesting.com>
Subject: [TowerTalk] Electrically lengthening a boom
From: mwdink <mwdink@clearwire.net>
Date: Mon, 30 Nov 2009 14:45:24 -0800
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
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|