[time-nuts] EFC info on Trimble 34310-T OXCO

[Charles Steinmetz]

Bert wrote:

>As I said before am waiting for the small spheres and will see what happens.

Monitor carefully, as I suspect the spheres will pack too tightly 
leaving too little airspace.  You could easily burn down an OCXO if 
this proves to be the case and the oven control loop goes 
unstable.  I'd put a thermal sensor on the OCXO itself for testing.

Even if it doesn't burn down, you could find that the oven 
performance is degraded by (i) instability or quasi-instability of 
the oven controller, or (ii) too much thermal resistance (remember, 
you want to add as little thermal resistance as possible).

On the other hand, mounting the OCXO as centrally as possible inside 
the outer enclosure on thermally non-conducting standoffs (teflon or 
nylon), with at least an inch of air on all six sides, has proven to 
work extremely well.

When I described using packing peanuts (or similar) to break up the 
airflow, it was in the context of having already mounted the OCXO as 
centrally as possible inside the outer enclosure on thermally 
non-conducting standoffs with at least an inch of air on all six 
sides.  And as I said, I have not found the additional step necessary 
once you have done this.  It may even be counterproductive.

Best regards,

Charles