I've got a foundation trench open right now. I've been thinking it is a great opportunity to keep some electronics at a very stable temperature. What's better then tossing it in a big hole in the ground then dumping a truckload of concrete on top? Likely the only thing I'll burry is a $2 temperature sensor. In So. California you don't need to go very deep to reach stable temp.
On Fri, Jul 13, 2012 at 5:25 PM, Neville Michie <[email protected]> wrote: > > You have to go deep into the ground to get stability. > At 15 metres deep there is a lovely pure sine wave of about 0.3C P-P. > I measured it on the roof of a cave, its period one year. > My design for the bolt is to put it in a 1/4 inch thick aluminium box which > is held at a constant temperature by a fan. Switching control is good > enough as the > thermal diffusivity of 1/4 inch aluminium will attenuate any spectral > components shorter than > a minute. The aluminium box is so conductive that the box is isothermal, > so once the bolt > has established its internal temperature gradients, nothing changes. > cheers, > Neville Michie > _______________________________________________ > 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. > -- Chris Albertson Redondo Beach, California _______________________________________________ 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.
