[time-nuts] Making a HP 10811 better

Rick Karlquist richard at karlquist.com
Tue Mar 30 18:16:38 UTC 2010


It has been interesting reading all the 10811 ideas.
I haven't had time to respond to them individually.
I would recommend reading my oven paper:

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

which will put some of the oven ideas in perspective.
With tweaking, we could get the thermal gain of the
E1938A over 1 million using just a single oven and
nothing exotic.  In production they ran in the several
100,000's.

I would also note that the 10811 has a fairly substantial
humidity coefficient of frequency.  Thus the first order
of business is to get the hermetic version of the 10811.
The common version that is open is never going to be
immune from the environment.

The E1938A was immune from humidity effects, even though
it was not hermetic.  It was nearly immune from temperature
effects as well.  It still had the same 2G turnover effects
as well as crystal frequency jumps, since the crystal was
essentially the same as the 10811 crystal.  You would never
mistake an E1938A for a Rb standard by looking at a strip
chart.  The best that any 10811 could do would be to
approach E1938A performance.

But go ahead, have fun and learn!

Rick Karlquist N6RK




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