Hi all,
I haven't read every message in this thread, but I think there's a variant of the D controller which has audio output. I think it's version C, but stand to be corrected on that.
Cheers,
Terry
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----- Original Message -----
From: Mike Duke, K5XU
To: [log in to unmask]
Sent: Sunday, April 19, 2015 10:40 PM
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
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