[time-nuts] Re: DOXCO from Z3801

[Bob kb8tq]

Hi

People on the list have written big long papers about just why ovens do what they do.
To get into all the details, those papers are a much better reference than some quick
messages on an forum like this. 

The quick and dirty version: 

There are a number of things that impact the temperature stability of an OCXO. Gradients
are a big factor. Your heat source, sensor and resonator are never all at a single microscopic
point within the device. Tear one open and that’s what you will find. Heat comes from over 
here, sensor is on that side, blank in the crystal package is here and has a thermal path to 
this over here. 

If you take an SC and fiddle the trap so you are in “thermometer mode”, you can measure the
thermal gain to the crystal. You will find that as you do this or that the gain goes up. Eventually
it changes sign and comes back down again. The higher it gets, the more likely some very minor
thing will have an impact on the gain ( = it’s a sharp peak ).