On 03/09/2014 01:09 PM, dave wrote:
On 03/08/2014 08:34 AM, DhiaDuit wrote:
Those push button car radios of years and years ago. They had a habit
of drifting off station. Every once in a while they needed to be re
set. I have about half a dozen of those old push button car radios.


I don't remember them as particularly drifty, and I grew up in the
Arizona Desert. They are usually Permeability Tuned (variable inductors)
which are much more stable than most variable capacitors in tuning duty.
Plus the IFs in those days were wide open and stations were allowed to
broadcast in HiFi.

Ferrite cores age, I am told. That could be a reason for a
slow drift (on the order or decades, perhaps).