jim,
Handihams provided a very similar indicator.  I used one on a Ham-m 
rotor for many years.  i put mine away after we moved and i moved in 
to the wire antenna age; promised the indicator to someone on the 
list and darned if I can find it again!!  i found it on a shelf one 
week and when I went back for it again, it had vanished!!  I'm 
guessing it was the man in the moon took it!  But it sure made the 
Ham-m accessible.
pat, K9JAUAt 10:47 PM 4/18/2015, you wrote:
>I don't think I have commented on this thread, but back in 1975,
>I had a HamAm rotor that turned my HighGain TH6DXX 6 element
>beam.  There was no way for a blind person to know the direction
>the antenna was pointing because the rotor meter was of course
>under glass and probably had a very small needle.  A friend at
>the time, built a small device, seems it was a voltage controled
>oscillator with a pointer knob on top that rotated freely 360
>degrees.  I would set the pointer in the direction I wanted to
>point the beam and hit the keys on the rotor.  When the tone in
>the speaker inside the attached box nulled out, I knew I was
>pointing northwest or where ever I needed to point.  I am not
>aware of any similar audible rotor indicators out there today.
>Jim WA6EKS