On Thu, 12 Aug 2004 09:06:46 -0400, "Charles Schuler"
wrote:


All component values drift with age. Your problem seems to be temperature
sensitivity or voltage sensitivity. For example, if the supply voltage to
the local oscillator drifts then the frequency will be affected. When you
are listening to an FM station at 100 on the dial, the local oscillator is
running at 110.7 MHz and a drift of only 0.1 % will throw the tuning way
off. That's why older receivers used AFC and newer ones use PLL frequency
synthesizers for the local oscillator.

Thanks. PLL synthesized tuners was probably what I meant when I said I
would look for "digital" radios. I'm a lot wiser know, thanks!

One last one, while I have I have you guys on the line: will the drift
"amplitude" of component values grow with age as well? Otherwise, it
would just be a matter of re-tuning, but that does not seem to help in
the normal case. These radio set drift away happily while listeing.

Per.