> I seem to remember an article in CQ or QST within the last 12
> months that addressed this very issue. As I recall the
> indicators being used were inexpensive digital voltmeters
> from All Electronics.
>
> Sorry, wish I could be more specific.......Maybe someone
> within the group will remember the specific article............GL
I didn?t see the article but I can imagine something like this: a stabilised
3.6V or 36V supply across either end of a suitably-rated 360-degree
potentiometer (rated to give a few milliamps standing current? Enough to
get stable readings, anyway, by cutting down contact noise), with the wiper
and cold end of the pot connected to a 3 digit digital voltmeter in the
shack. By setting the correct range and positioning the decimal point
approporiately on the voltmeter, the voltage reading should directly
indicate degrees. It'll need some RF suppression I expect.
Here's a CAD-CAM circuit diagram professionally prepared at great expense
[not]:
www.g4ifb.com/rotator_direction_indicator.jpg
The electronics seem relatively simple. Mechanically coupling the pot to
the mast for a 1:1 turns ratio is likely to be more of a challenge involving
pulleys, belts, rubber drive wheels or chains stripped from an old printer
or scanner maybe. If your beam turns past 360 degrees, you'd need, say, a
450 degree pot, assuming these are available, or mechanical reduction from
the beam's full travel down to the pot's full travel, setting the voltage
accordingly (e.g. 45V = 450 degrees). For more accuracy, a 10-turn pot with
suitable mechanical reduction would work too, I guess. Just don't forget to
position the pot at 0 volts for 0 degrees!
73
Gary ZL2iFB
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