[time-nuts] Practical considerations making a lab standard with an LTE lite

[Alexander Pummer]

Schomandl -- the company which made the first indirect synthesizers in 
the sixties in the past century -- used buried crystal oscillators as 
standard frequency source, 12meter deep in the companies yard in the 
Belfort Strasse in Munich, Bavaria Germany, ...Rohde& Schwarz also had 
buried oscillators. I have one in California, where, the temperature at 
10m deep is 15,784C° around the year, and measuring the frequency off 
set between wwvb's harmonic and the buried oscillator originally tuned 
to cca 3MHz, to the natural serial resonance of the crystal, by counting 
the beat -- to a harmonic of wwvb, cca 4217Hz , 364 358 801 pulses per 
day, as of Nov 2014, counter resets by wwvb daily, daily changes max ± 8 
pulses, are to see, but a yearly decrement of 15 to 8 pulses per year, 
less per year in the last time is observable the "system down there"is 
running since 1991.
73
KJ6UHN
Alex


On 11/23/2014 8:46 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
> On 23 Nov 2014 14:45, "Bob Camp" <kb8tq at n1k.org> wrote:
>> Hi
>>
>> If you have a basement in your house / building
> I do not.
>
>> —and —
>> it’s dry and reasonably draft free (no garage doors opening up from time
> to time)
>
> My lab is a room which is part of the garage! Just about everything is
> against me with this method,  BUT you do give me an idea...
>
> You got me thinking about the possibility of actually mounting the TCXO
> burried in the ground!   The temperature of that is not going to change
> very rapidly.
>
> FWIW, I know a guy that did work as an air conditioning engineer,, but now
> works for a company selling geothermal heating.  He installs  ground source
> heat pumps for the geothermal energy.  He says that they actually work
> quite poorly in many cases. In a couple of years the temperature of the
> ground falls as the heat is extracted faster than it replenishes.  So the
> efficiency falls off. I don't think that the TCXO would heat the ground
> faster than it dissipates away.
>
> Of course there would be some practical issues burying the TCXO, but those
> would not be insurmountable ones. I have no idea what depth might be
> needed.
>
> My wife thinks thinks I am a nutcase - that would only confirm it to her!
>
> Dave, G8WRB
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