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Topband: Gamma matching crank-up tower

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Subject: Topband: Gamma matching crank-up tower
From: (Jim McDonald)
Date: Wed, 23 Oct 2002 21:37:14 -0700
I now have an inverted vee hung at the top of my motorized US Tower 89'
crank-up (the one that is rated at 30 square feet in a 50 mph wind).  I know
I should have a modeling program, but I don't, so I'd appreciate any
suggestions on a starting point for a gamma match.

The tower has a Force-12 C-31XR at 90', a Force-12 Mag-340 (not the "N") at
about 100', and a Diamond F-22A 2M vertical (AR-Cluster antenna) at the top
of the 20' mast, which is at 105'.  The coax cables (one for VHF and another
to a DX Engineering remote switch), remote switch cable, and rotor cable
hang from the top coax standoff arm through the lower ones.

I don't have any radials now, though I can install some.  Due to a horse
barn about 50' away, the house, a fence, etc., a radial system can't come
close to a full circle.  I do have what I think is an adequate lightning
ground, consisting of several 8' rods near the base of the tower and between
it and the house.  I also have the tower ground tied to a pipe fence for the
horse corral.  The perimeter is maybe 300', and it's connected to the metal
horse barn.  The cables go through ICE arrestors on the rods and are buried
in a trench t the house.

Any suggestions would be appreciated.  (I imagine the first will be to start
burying wire.)  Another suggestion could be to not use the tower due to the
cables and its being a crank-up; that actually wouldn't surprise me.
Anyway, thanks vey much.

Jim McDonald - N7US
Mesa, Arizona

N7US AR-Cluster:

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