[time-nuts] A different timenuts interest

J. Forster jfor at quik.com
Wed Jul 21 22:57:33 EDT 2010


> I remember one someplace in London too.

Science Museum in South Kensington, I'd expect, but I've not been there
20+ years.

-John

> Someone mentioned temperature compensation. What would you need to
> compensate for? Temp change in the wire wouldn't effect the rotation
> as far as I can tell. Swing length might be different based on temp of
> the wire I guess, but with a long pendulum, I think the magnet is
> going to way overcome that issue.
>
> The one @ RPI had issues due to air movement in the shaft, but that's
> a different problem.
>
> I suppose the right method is to use a GPS disciplined oscillator and
> the appropriate divider to drive the magnet under the floor. :) To cut
> down in draft induced drift and jitter, you'd have to put the whole
> thing in a vacuum though!

You don't want to drive it from a clock, IMO. You want to make it a
free-running oscillator. Period is irrelevant.

-John

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