[time-nuts] Thermal insulation choice?

[John Ackermann N8UR]

On 1/6/2012 4:14 PM, Rick Karlquist wrote:

> Before making this into a science project, consider this data
> point:  We converted the oscillator in a 10811 to run in mode
> B at 10.95 MHz.  The tempco in mode B is about 30 ppm per degree
> C.  Needless to say, the converted 10811 was extremely sensitive
> to crystal temperature.  I could wave my hands around it and notice
> the temperature change from the air currents.  However, simply
> putting the 10811 into a small empty cardboard box completely
> solved this problem.  No rocket science necessary.  So in the
> short term, this simple box was like a double oven.  Of course,
> in the long run, the 10811 thermal gain is only 1000 or so and
> you can see the effect of the HVAC shutting down at 7PM, etc.

That's interesting, Rick.  I was also thinking that just still air was 
most of the battle, but since I have the opportunity to do it "right" 
within reason and this is a fairly major project, I thought that adding 
some additional thermal isolation couldn't hurt, so why not? 
(time-nuttery, etc.)

John