[time-nuts] Morion MV89A position

[EWKehren at aol.com]

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,  
csteinmetz at yandex.com 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



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