In the 70's I did a 4 inch pipe 20 feet in the ground in Dallas. Temperature was better than 0.1 C. Got canvas coin bags from my local bank filled them with sand and lowered them one at a time with line each one a subsequent number. Used it for 18 years. Bert Kehren In a message dated 1/29/2014 8:46:29 P.M. Eastern Standard Time, [email protected] writes:
Dave wrote: >what about replacing your aluminium box with a, say 2 foot piece >of 6 inch pvc pipe (ocxo suspended inside it clear of the wall and >sealed off ends) and burying that a few feet in the ground? I share Poul-Henning's lack of enthusiasm for burying electronics. But if you try it, I'd be interested in hearing how it works. Depending on your climate, you may need to go deeper than a few feet to achieve a reasonable approximation to isothermy. Of course, even a few feet should get you to where the rate of change of temperature is quite slow and the peak-to-peak swing is lower than the outside air temperature. (But is that the standard? Aren't most time-nuts labs in climate-controlled living spaces?). If you really want to go nuts, it's pretty simple to put the cast aluminum box into a larger enclosure with a small, thermostatically controlled fan. If you bond a temperature sensor to the inside wall of the cast box, it's easy to hold the temperature of the cast box to well within 0.1C. Best regards, Charles _______________________________________________ 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.
