Factory radio question - Signal won't stay locked on the tuned station

[chrisntam]

I got an am fm non stereo radio (1970) refurbed by a radio restorer I found in Hemmings.

Pretty much ever since I got it back, I find that it won't stay "connected" well with a radio station.  I constantly have to "retune" to get it locked back in.  I use mostly FM, not real sure about AM.

I'd read somewhere this is common with an analog radio and today's digital signals.

True?

Does your factory radio behave the same or does it stay locked on the signal?

[J. Gomez]

I got an am fm non stereo radio (1970) refurbed by a radio restorer I found in Hemmings.

Pretty much ever since I got it back, I find that it won't stay "connected" well with a radio station.  I constantly have to "retune" to get it locked back in.  I use mostly FM, not real sure about AM.

I'd read somewhere this is common with an analog radio and today's digital signals.

True?

Does your factory radio behave the same or does it stay locked on the signal?

chrisntam,

The term you are describing is what is reference to “frequency drifting” which the local radio oscillator do not stay lock in the same radio frequency.

You may need to ask the rebuilder if the modification unit has the old AFC (automatic frequency control) switch. In older FM radios this was common to include an AFC switch which was a circuit that adjusted the oscillator to compensate for drifting. In modern unit this is done different by adding a PLL circuit to hold the frequency.

I do not think we have any issues with station propagation around the DFW metroplex when one station fades in and out, although this not related to drifting.

There is also the tuning and adjustment that would need to be made to the radio, although the restorer would/should had made but you need to check with him.

Good luck…!

[bcroe]

Auto Freq Control was never used on AM radios because they hardly
ever drifted off.  FM tuning is more sensitive, but should only rather
infrequently need retuning.  With the AFC circuit functional it should
just stay always.  Just maybe, your radio has a mechanical issue that
lets the tuner move with vibration for both AM and FM.

A digitally synthesized radio wil never drift at all (even if the station
did).  Uses an internal super stable crystal.  Bruce Roe

[TJ Hopland]

I was going to ask about a mechanical vibration issue.   I had a few where that seemed to be the problem.  That may be a question for the re builder,  there may be something that can be tensioned differently to deal with that.