[time-nuts] GPS disciplined mechanical clocks

Bill Hawkins bill at iaxs.net
Wed Mar 4 21:33:55 UTC 2009

Don and group,

I was about to write about the "pendulum as a VCO" concept. I've seen
articles in the NAWCC Horological Journal that describe ways to do it,
but have been hesitant to do anything to my grandfather's Seth Thomas
wall clock. It gets wound once a week, and generally doesn't need

One thing about an old clock, though. The minute hand can be off by a
minute on either side of vertical due to gravity and  wear of the gears.

"Anathem" surprises on many levels, especially the 'alien' encounter.
Excellent "elsewhere" read, far from the daily news.

Bill Hawkins

-----Original Message-----
From: Don Latham
Sent: Wednesday, March 04, 2009 1:22 PM

I've driven "quartz movement" clocks with one pps signals, bypassing the
"quartz" works. To synchronize pendula (?) is relatively simple, but
best done using a mechanical/magnetic impulse phase locked loop,
considering the pendulum as a VCO.
BTW, I recommend Stephenson's new effort, "Anathem" loosely based on the
clock of the Long Now Foundation, q.v.
Don Latham

Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304

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