[time-nuts] GPS disciplined mechanical clocks

Neville Michie namichie at gmail.com
Thu Mar 5 08:35:34 UTC 2009

Hi Jim,
a "seconds Pendulum" has  frequency of 0.5Hz, and so your subwoofer  
would need 0.5 hz response if it is going to shake walls.
Being a purist I must point out that at 0.5 Hz the sound energy would  
be in the form of pressure which is very weakly coupled to a pendulum.
The only coupling would be buoyancy, and that would need a 1Hz signal  
to give two reductions in apparent gravity per cycle.

Allied to this discussion is the Loomis effect, discovered by the  
American millionaire who had three Shortt clocks running in his  
They synchronised unless aligned at 120 degrees to each other. I  
wonder weather they were shaking the bedrock, or maybe the gravitational
attraction between the 10 kg pendulums may have synchronised them.  
(See "Tuxedo Park" by Jennet Conant) He qualified as the first time nut.

cheers, Neville Michie

On 05/03/2009, at 5:22 PM, Jim Palfreyman wrote:

> So if I set my GPS locked 3325B to 1Hz (sine wave) and put that  
> into my M&K
> subwoofer and sat that next to my pendulum clock (with its ~1m long  
> Reifler
> pendulum) it should keep perfect time.
> Beauty!
> 2009/3/5 Tom Van Baak <tvb at leapsecond.com>
>>> mechanical, more of a hybrid, but I don't know how you'd  
>>> discipline a
>>> mechanical clock with a system that had to drive in parallel with  
>>> the
>> escape
>>> mechanism, the two would fight each other.
>> Eric,
>> Precision pendulum clocks, when mounted near each other,
>> have been known to eventually get into phase lock. So one
>> idea is to add a GPS 1PPS driven bass speaker or solenoid
>> or some sort of thumping contraption. Perhaps eventually the
>> pendulum clock would lock to the vibrations on the the wall.
>> /tvb
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