As an additional data point.. When experimenting with various forms of insulation for a thunderbolt board I found that a corrugated carboard box provided a noticeable decrease in temperature fluctuations while limiting the overall temperature rise. Even small ammounts of additional insulation (ie. a few layers of thin flexible foam sheets maybe 2 mm thick used for wraping items for shipment) caused the temperature as reported by the thunderbolt to increase signficantly. (Maybe 15 Deg C IIRC ?)
--- On Fri, 1/6/12, Magnus Danielson <[email protected]> wrote: > From: Magnus Danielson <[email protected]> > Subject: Re: [time-nuts] Thermal insulation choice? > To: [email protected] > Received: Friday, January 6, 2012, 6:10 PM > Rick, > > On 01/06/2012 10:14 PM, Rick Karlquist wrote: > > 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. > > This is essentially what I've found quite useful at many > times, quick air fluctuations affects crystals pretty good > but just blocking the air helps to slow down things. > Long-term creeps through but is not on the same scale. > > A large enough cardboard box will leak over-temperature > such that the oven keeps working. > > Cheers, > Magnus > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
