"Nicolae Santean" ) writes:
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Hello everybody,

I have a technical question about old analog receivers.

How difficult would be to replace/modify the local oscillator(s) of an
analog receiver in order to make it PLL? Is it actually feasible?

Thanks a lot,

Nic. Santean
http://www.csd.uwo.ca/~nic

YOu disable the existing local oscillator, and feed in an external oscillator
at that point. Really quite simple, as long as you have the external
oscillator.

But, it gets trickier depending on the receiver. The old single conversion
types with a low IF would have the front end tuning ganged with the oscillator
tuning. If you add an external oscillator, you now have two knobs to turn as
you tune. More important, if the IF is a small percentage of the signal
frequency, this lack of tracking will probably mean you'll be tuning the
image frequency one moment, and the desired frequency the next.

Michael