[time-nuts] Crystal ovens

Rick Karlquist richard at karlquist.com
Wed Jun 10 18:16:22 EDT 2009


jmfranke wrote:
> There was an interesting paper by W. A. Morrison (made the first crystal
> controlled clock) in the July 1928 issue of Proceedings of The Institute
> of
> Radio Engineers, pages 976-980, entitled "Thermostat Design for Frequency
> Standards."
> The article describes a crystal oven consisting of four layers: starting
> at
> the outer wall - a layer of insulation, a heater, a distributing layer,
> and
> an attenuating layer.  He described a case wherein the temperature
> variation
> is reduced by a factor of "at least 10,000 to one."
>
> Of course this was for a passive crystal versus an active oscillator.
>
> John  WA4WDL
>

"10,000 to one" (thermal gain = 10,000) is very good.  We
could not achieve that until we applied the techiques in
the following reference:

http://www.karlquist.com/oven.pdf

We eventually demonstated thermal gain of over a million.
Again, for just a crystal.

Rick Karlquist N6RK







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