I've been to this street and I never want to return... :)
The pots are changing their resistance with humidity and especially
temperature. In addition, RF can leak into your cable and superpose to the
DC voltage resulting false readings.
73 de Zoli HA1AG
> look for a DVM kit.They are cheap around 15us$ here.You can
> find them in LCD versions or LED version.
> whit a 500ohm pot (this one is not cheap,you find them at
> fleamarkets) ,at
> the rotor (driving by a belt).Put a 12vdc on this pot and in
> the schack you measure the
> voltage,build a voltage divider sytem whit 2 pots(linear) for
> 0° and 360° and you are set.
>
> 73
> on4ma
>
> ----- Original Message -----
> From: <Zoltan.Pitman@libertel.nl>
> To: <glenn@gi0kvq.co.uk>; <antennas@qth.net>;
> <towertalk@contesting.com>
> Sent: Thursday, November 01, 2001 9:25 AM
> Subject: RE: [TowerTalk] Homebrew Rotators
>
>
> >
> > Hi Glenn,
> >
> > I suggest to do the following:
> >
> > 1, Create azimuthal maps centered on your QTH. There are
> many free SW for
> > this purpose available on the internet. My preference is
> AZMAP by Paul AA6Z.
> >
> > 2, Print the map and affix it on a piece of plastic board.
> >
> > 3, Drill a 3mm hole at every 15 degrees for LEDs.
> >
> > 4, At the rotator drive a small rotary switch which has 24
> positions. With
> a
> > diode matrix I reduce the number of wires needed back to the shack.
> >
> > You will get a very reliable system providing very visual readout.
> >
> > Best regards,
> >
> > Zoli HA1AG
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: Glenn Millar [mailto:glenn@gi0kvq.co.uk]
> > > Sent: 28 October, 2001 19:54
> > > To: antennas@qth.net; towertalk@contesting.com
> > > Subject: [TowerTalk] Homebrew Rotators
> > >
> > >
> > >
> > > Working on a project here to make a homebuilt rotator. While
> > > the mechanics
> > > of the system are fairly straight forward one problem is with
> > > the direction indication.
> >
> > > However I was wandering does anyone on
> > > the list know of or could suggest any alternatives, using
> > > products that are
> > > easier to find or less expensive.
> > >
> > > Many thanks
> > >
> > > Glenn
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