[Heathkit] Tubular Ceramic Capacitor

[Drew P.]

Heinz wrote:

[snipped]

"Tubular ceramic capacitors were available with different temperature
coefficients to allow a free running oscillator to be on frequency over
a wide temperature range. The temperature coefficient was indicated by a
colored spot on the body of the capacitor.
Inventions in ceramic materials with different temperature coefficents
were made in the thirties. Germany had no raw material for making
crystals. All Wehrmacht equipment depended on free running temperature
compensated oscillator circuits."

Thank you for a most fascinating glimpse into German radio history!

I would imagine that this type of frequency stabilization expertise was applied in German radio equipment for a couple of decades after the war. German equipment, then, would seem to be worth looking for.

Drew