[time-nuts] time-nuts Digest, Vol 70, Issue 31
contact at clocktrust.com
Thu May 13 08:40:41 UTC 2010
A potted history. Before I start a warning I suffer from dyslexia and
twitter like a buddie, not a god combination. The aim of the effort in
writting this is to forge a way forward to get young people involved with
the concept of time and the recording of it. Hence www.timemachinefun.com .
Also to preserve the industrial heritage. Another sad day, yesturday, an
important shortts derivate 'frequency standard' went under the hammer. I
hope the buyer realises what they have brought and need to be done to record
and preserve this clock/oscillator.
Its quite a while ago that the pendulum was used as an oscillator. In fact
it was a triple shortts pendulum clock that helped develop quartz
oscillators, in the bell insititute. They needed a 'rock solid' (gravity)
reference and at the time the Shortts clock was it.
The pendulum, giving low frequency oscillation, was a mass and a rod.
Temperature compensation was soon realised and too the affect of humidity
and air pressure. The other major problem was circular error. So low
amplitude, in a vacumm! The other compromise, how to keep the pendulum
going, so it acted like a pure pendulum. It took 300 years of history to
think outside the box, a free pendulum, first in production the Shortts
clock, retailed by synchronome.
When the first one was formed it went up the the Royal Astro of the time. He
first measured the gravity of the earth, over the month the moon, then the
sun, then the flux due to the wobble of the earth. They knew they had struck
gold, but it was the end of the pendulum. These elements could be
compensated for, but not controllable, they needed something to beat, that
was independent of the solar system and something a bit quicker than parts
of a second. The rest is history.
If you did compensate for variation of the solar system, you would just peel
another layer off, you would have to cater for any mass (all mass has
gravity), even a rain drop or us. We have a Huws model of the shorts clock
in the TimeMachineFun museum and other technology advances, towards
synchronisation of society. Just got on display the BBC 1960 crystal
We take time and frequency synchronisation for granted, without it the whole
fabric of society would revert back to a much distant time. A time you could
walk around London, go from church to church, take 30 minutes to do so and
the time was the same on both dials. From the mechanical age, to electric,
broadcast, electronic and computer, we have now divided time so precise and
small, its atomic. Again in the computer age its the division of time that
holds us back, also making smaller and smaller circuits, running at highwer
and higher frequencies. Its not steam trains colliding, or data on bus's its
messing around with groups of particles.
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