[R-390] wow... the R-391A does exist - Video Update

[Robert Nickels]

Barry Hauser wrote:
> Also notice when you play the video -- it does not seek the shortest 
> path, so to speak -- it cycles through all or most of the way in one 
> direction, then reverses.
Very cool videos, thanks Ray for posting them.

Can anyone explain how the R-391A auto-tuning is accomplished?  Given 
the technology available at the time, I'm guessing it might counts 
pulses from a cam-actuated electromechanical contact, with one or more 
stepper relays as the memory element.   But I know the auto-tune 
transmitters use a phase comparator and closed-loop analog feedback, so 
an all-analog design using a multi-turn pot would be another 
possibility.  Either method could  explain why it seems to drive to a 
"home" position and then reverses direction.

73, Bob W9RAN