Hi A metal shell inside a metal shell pretty well takes care of everything. Gradients, transients, drafts, what ever. You don't need super thick stuff. Bud chassis, Hammond boxes, copper pipe, PC board material, or soldered brass flashing all will do the trick.
Simply tossing a fluffy towel over the unit works amazingly well if drafts are the only real concern. Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rick Karlquist Sent: Friday, January 06, 2012 4:15 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thermal insulation choice? John Ackermann N8UR wrote: > I am looking for a readily available (from Home Depot or other local > source) insulating material to use in a chassis that's housing a > sensitive OCXO. My goal is just to slow down any external thermal > transients so the oven loop has time to react gracefully. 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. Rick Karlquist N6RK _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.