[time-nuts] Measuring the accurcy of a wrist watch

DaveH info at blackmountainforge.com
Sat Apr 19 01:37:51 EDT 2014


Hi Chris

My concern was not the magnetization of the watch movement but the induction
of eddy currents into the balance wheel which will cause drag.

The act of moving the watch into the field of the pickup could cause the
watch to start running more slowly. You will be getting a strong signal but
it will be the wrong signal.

Dave

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Chris Albertson
> Sent: Friday, April 18, 2014 08:44
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Measuring the accurcy of a wrist watch
> 
> On Thu, Apr 17, 2014 at 11:12 PM, Hal Murray 
> <hmurray at megapathdsl.net>wrote:
> 
> >
> >
> > Steel makes very good springs.  Are there any non-magnetic 
> materials that
> > are
> > close?
> >
> 
> I think they can use some kind of non-magnetic stainless steel
> 
> Also this might be a moot point because I got a good strong signal by
> placing the watch on top of the guitar strings.  I did not 
> have to restring
> the guitar.   The wall clock works even some inches away.  
> You don't have
> to get really close to the magnets.   If you were building a 
> sensor, just
> use a plain iron core and 1/4 pound of #40 wire
> 
> >
> >
> -- 
> 
> Chris Albertson
> Redondo Beach, California
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