[time-nuts] Making a HP 10811 better

Tom Van Baak tvb at LeapSecond.com
Sun Mar 28 22:44:09 UTC 2010


> I have not had problems with My G changing short term, (BUT it would be 
> interesting to see if I can detect the moon overhead).

Warren,

Lunar/solar tides change g at roughly the 1e-7 level over an
interval of 6 to 12 hours. The g sensitivity of a 10811 is on
the order of 1e-9. So the quartz oscillator you're looking for
needs to be stable to well below 1e-16 at tau 10k to 100k s
to detect the moon. Sorry. Meanwhile, precision pendulum
folks have had success turning their clocks into gravimeters.

Now if you really want some fun connect your OCXO to a
one meter cable and let it swing like a pendulum clock. You
should see some very nice sinusoidal FM as it goes back
and forth. Devise some sort of mechanical, compressed air,
or magnetic impulse system to keep it running like that all day.

/tvb

Thunderbolt +/-g times 3-axis:
http://www.leapsecond.com/pages/ocxo-2g/TBolt-2g-6axis.gif

More on tides and clocks:
http://www.leapsecond.com/hsn2006/





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