[Milsurplus] BC-221Tempature compensating Capacitors

[C Whitaker]

de WB2CPN               Pre-1950
The BC-221's we had ran on batteries, so they
weren't left on a long time.  Also, they were usually
used on frequencies that were well below 7 MHz.
And, on formal nets there was a Beacon Station that
one tuned the receiver and transmitter to.  Or to the
Net Control.   There were a few ways to calibrate
the Xtal, but they usually involved the use of a long
handled screwdriver and a couple of large GI towels
to wrap everything  in.  Trick was to let it warm up for
about the same length of time as it would be ON if you
were going to use it. 
73  Clete