[time-nuts] Chronometer contest sponsored by IEEE Spectrum

[michael taylor]

On Nov 30, 2007 1:04 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>
> > With a little work you might be able to precisely  calculate the
> > maxima of the parabola and precisely set the frequency  independent of
> > temp and aging.  Ha!
>
> What's the aging like for watch crystals?

>From a 32.768 kHz crystal taken at random (Fox Electronics)
<http://www.foxonline.com/pdfs/ncseries.pdf>

Aging: +-3ppm/year

> What type of cut to watch crystals use?  Are there any generalizations about
> aging?

I believe the type of cut is just called "tuning fork", but I am not sure.