[time-nuts] Morion MV89A position

[Dave Brown]

Thanks- What I'm interested in achieving is the lowest posible energy 
requirement for a set of quartz frequency stds. It seems to me that using 
the close to iso-thermal 'hole in the ground' arrangement is a useful step 
in that direction as it should minimise the power necessary for 
environmental control.
 When we had the bad quakes here back in 2010/2011 I lost all power to the 
gear for several days and the backup batteries only held it running for 
about 36 hours. This, after the oscillators had been running continuously 
for 7 years.  So, rather than invest heavily in a higher capacity battery 
bank, I'm looking to get the lowest energy requirement for the essential 
things like reference oscillators and a minor amount of logging eqpt. 
Inconvenience re access etc is a minor issue in the overall scheme of things 
from my point of view.
I guess I may have to just try it.

Regards
Dave Brown
 Christchurch, NZ



----- Original Message ----- 
From: "Charles Steinmetz" <csteinmetz at yandex.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Thursday, January 30, 2014 2:44 PM
Subject: Re: [time-nuts] Morion MV89A position


> 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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