Is this audible rotor control box indicator something a lot of people is
interested in?  


-----Original Message-----
From: For blind ham radio operators [mailto:[log in to unmask]]
On Behalf Of Mike Duke, K5XU
Sent: Sunday, April 19, 2015 4:41 PM
To: [log in to unmask]
Subject: Audible Direction Indicator

Instructions for building one were in a QST Hints and Kinks in either 1979,
or maybe 1980.

I think this is the same circuit that HandiHams built.

To connect the circuit, all you have to do is determine which terminals on
the back of the control box receive the voltage change caused by the
changing value of a pot in the rotor which turns along with the antenna. For
my HD73, I believe that is terminals #2 and #5, but don't quote me on that.

The circuit is basically a wheatstone bridge that is connected across the
two control box terminals that receive the voltage change from the pot in
the rotor to drive the meter in the control box. The wheatstone bridge in
turn drives an audio osilator. When the voltage on the meter is equal to
that of the reference circuit in the bridge, the tone is nulled out.

By having a scale, or at least a few tactile marks in key places around the
knob of the pot in the reference circuit, you can set the pot so that you
get a nul when the antenna is pointed in the direction you want.

Of course, the scale must be set up with the help of someone who can read
the meter on the control box. But once this is done, you are in business.

I may have the schematic somewhere. If I can find it, I will put it where
folks who want it can get it, and post that information here.

--
Mike Duke, K5XU