Your stepper motor tuning loop would have to be closed on the received
signal strength for it to be of any use in an analog tuning system. Simply
driving the motor open loop to a preset dial position may not be repeatable
enough. Also, the stepper drive system would have to have sufficient
resolution for it to be able to correct for drift with this closed-loop
approach. That is the big advantage of the PLL over a manual tuner.


"Rick Andrews" wrote in message
...
...
Speaking of which, since the car radio I'm using has analog tuning, what's
the expert opinion on using a good stepper motor and an RS-232 interface
to
control tuning with a PC?
I thought it'd be nice to have infinite presets, and maybe even a relay
controller for switching crystals. But again, I thought I'd check here
first.

-Rick