Re: Variable Capacitance and Inductance

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 5/23/02 10:14:49 AM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:


>
> Original poster: "David Thomson by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <dave-at-volantis-dot-org>
>
> Hi Gary,
>
> Radios are tuned to crystals precisely because inductor/capacitor only
> circuits do drift.
>
> Dave


Hi Dave,

The vast majority of  receivers in the world don't use crystals for the local
oscillators. The commercial transmitters that use them and the tiny number of
military receivers that do, keep them in temperature-controlled environments,
because even a crystal's frequency IS temperature sensitive (drift). My first
full-time electronics job was building "crystal ovens" for high precision
military communications equipment in '63.

Matt D.