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Topband: Switching in Extra Antenna Length

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Subject: Topband: Switching in Extra Antenna Length
From: (John Kaufmann)
Date: Wed, 3 Jul 2002 21:21:02 -0400
W1JR wrote:

> In the 1980's, Colatchco (W1FC and W1CF/SK) sold, among other things, an
> 80/160 meter vertical which I believe had a relay switch. Perhaps someone
> can bring that info forward since they must have had a viable solution. I
> don't think they used a trap!

Joe et al,

You are mostly correct--Colatchco did have a 80/160 vertical.  W1CF, who
lived a few miles from me, did have a prototype that used a relay to switch
in a 160m loading coil about 2/3 the way up the vertical.  A wire run inside
the vertical supplied DC power to the relay.  A small wire top hat connected
to the vertical just above the loading coil.  It was a 60-foot high antenna.
However, I don't believe they ever marketed this version, or if they did,
they only sold a few.

I have some old Colatchco product literature which does describe a 80/160
vertical, 42 feet high, which used an "encapsulated resonator" at the top of
the vertical and acted "as a loading coil on 160 and as a trap on 80".  It
did not use any mechanical switching.  It also had a small wire top hat
above the resonator.  This was the version that I believe they did market
although I'm not sure how many they sold.

73, John W1FV

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