The Ham-M rotors have a potentiometer built into the rotor so that the
resistance changes as it rotates.  The meter detects this and translates it
into direction.  An audio oscillator with matching resistances can be used
to tone match and know what direction the rotor is pointing.

At 07:19 PM 3/11/02 -0500, you wrote:
>Yes, I have an HD-73 that I never know where it is pointing!
>73, de Lou K2LKK
>At 07:36 PM 3/10/02 -0500, you wrote:
> >Yeah, I'd like a copy too, Tony, if you have it.  I generally don't archive
> >my QST's that far back.
> >
> >Another use I had for my Carl Conway meter was to use it across the meter of
> >an old  rotor.
> >
> >It seems to me there was a device for reading the direction on a Ham-m
> >rotor, if anyone has info on how to adapt a rotor to know its direction,
> >please share it with the list.
>
>Louis (Kim) Kline, A.R.S.  K2LKK
>e-mail:  [log in to unmask]
>Work e-mail:  [log in to unmask]
>Work Tel.  (585) 697-5753