I just chatted on RTTY with someone who'd done this. He used gearhead
motors for driving the tuning components, with additional gearing from
a BC-375 TU, for the cap I would think. And he used potentiometers
for feed back, a multiturn geared 2:1 for the roller inductor.
Voltmeters are used as the indicators.
And on that subject-
Has anyone taken the Antenna Load assembly for the AM-3349/GRC106,
such as the unit Fair Radio is selling, and successfully turned it
into either a manual or automatic tuner? It looks like a good piece
of gear, but it's also $250.
73, doug
From: "Jim Lux" <jimlux@earthlink.net>
Date: Sat, 29 Nov 2003 06:59:50 -0800
----- Original Message -----
From: "Colburn" <kd4e@arrl.net>
To: <towertalk@contesting.com>
Sent: Friday, November 28, 2003 6:07 PM
Subject: Re: [TowerTalk] Best tuner value? (I think that was the topic)
> Jim Lux wrote:
> > I don't know that I'd try to do something like modifying some ancient
> > hamfest special (high quality as it may have originally been) with
steppers
> > or servo motors. Too many potential problems, mostly mechanical in
nature.
>
> Actually, three sets of selsyn motors might do just fine, since they
> track perfectly one with another ... that is if you can find them!
But selsyns don't do multiple turn counting.. Maybe with some sort of
gearing they would, (i.e. 1 turn of selsyn = many turns of cap or inductor).
For a conventional 1/2 turn cap they'd work just fine, and be fast, although
I'm not sure how precise they'd be (or need to be)
>
> Only other things you'd need would be a remote antenna switch and a
> remote sensor for your SWR/PWR meter.
Remote switches are already available, of course.
The SWR could be measured at the Tx end of the feedline (hopefully, your
tuner lets you get fairly well matched, so the loss of the line is not
significant)
Jim, W6RMK
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