[time-nuts] Improving the stability of crystal oscillators

Brooke Clarke brooke at pacific.net
Sat Oct 13 21:40:25 EDT 2007

Hi Bruce:

Details on your experiment please.
Hole/pipe diameter, material?
Delta T at different depths vs surface ambient?
Soil type?

Have Fun,

Brooke Clarke
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam

Bruce Griffiths wrote:
> ); SAEximRunCond expanded to false
> Errors-To: time-nuts-bounces+brooke=pacific.net at febo.com RETRY
> Brooke Clarke wrote:
>>Hi Bruce:
>>I've also looked into drilling a hole (garden hose, 90 deg fitting & pipe with 
>>end smashed flat to make a nozzle will easily drill as deep as the pipe is 
>>long).  Then using a short length of capped copper pipe at the bottom and the 
>>rest PVC.
>>Like I think here in California wine country 4 feet would be plenty deep.  But 
>>this method only works at your home location.  Not too good for a clock that 
>>will be sent to someone else.
>>I think the long time constant method can be done in a few cubic inches.
>>Have Fun,
>>Brooke Clarke
> Brooke
> The required depth depends on the soil diffusivity and the temperature
> stability required.
> It is instructive to install thermometers at depth intervals of a foot
> or so and record the temperature fluctuations experienced by each
> thermometer.
> This was first done around 1860 by Forbes.
> I repeated the experiment in 1966.
> Bruce
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list