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

Ulrich Bangert df6jb at ulrich-bangert.de
Wed Apr 16 09:21:13 EDT 2014


Tom,

can you explain what exactly you understand by "a large coil of wire"?

Did you make the easurements on the Junghans with a DIY sensor or with one
of the commercially available?

I have made some basic tests with a coil coming from a loudspeaker's cross
over network. It has a few hundred windings, R=1.3 Ohms, 2.3 mH, but the
only thing i receive with this coil is a strong 10 Mhz signal...perhaps no
real surprise in a time nuts laboratory.

Best regards

Ulrich

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von Tom Van Baak
> Gesendet: Dienstag, 15. April 2014 15:53
> An: Discussion of precise time and frequency measurement
> Betreff: Re: [time-nuts] Measuring the accurcy of a wrist watch
> 
> 
> > Some research has shown that there is an comparable instrument for 
> > ANALOG quarz watches. As far as I understand it does not 
> try to detect 
> > the quarz frequency but detects magnetic pulses from the 
> step motors 
> > that move the hands of the watch.
> > 
> > Has anyone of you ever tried to do this in a time nuts laboratory?
> 
> Ulrich,
> 
> Yes, this works well, for both those with seconds hands (one 
> magnetic pulse per second) and those with only minute/hour 
> hands (one or two steps per minute). A large coil of wire is 
> all you need. Have a look at the watch timing tools and 
> sensors at http://www.bmumford.com/microset.html or 
> http://www.bmumford.com/mset/modelwatch1.html
> 
> Here's an example using a magnetic sensor: 
> http://leapsecond.com/pages/Junghans/
> 
> /tvb
> 
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