[time-nuts] Sidereal timekeeping

Attila Kinali attila at kinali.ch
Mon May 16 07:14:51 UTC 2011


On Mon, 16 May 2011 00:01:54 +0200 (CEST)
"iovane at inwind.it" <iovane at inwind.it> wrote:

> >Heh.. I cheated and used a 3325B to make whatever frequency we wanted. 
> >(even better, you can use GPIB to change the frequency vs time to make a 
> >"clock" that displays unusual things like "height above horizon" or 
> >"azimuth to orbiter")  Whether this would be more useful than just 
> >driving a dial with a stepper motor is sort of a good question.
> 
> If a 32859 crystal was easily available, that would be a fantastic solution.

Such crystals are easily available. It's just that the usual suspects
(digikey, farnell,..) do not sell them, as they have not enough volume.
Easiest to get them is to call your local sales rep of a crystal manufacturer
and ask him what options he has. Usually you can get away with buying a dozen
or so of a custom frequency, at the cost of a couple USD each. If you can
get one of the "tunable" types, you should be able to get single pieces
at a reasonable price.

Of course, the stability of those crystals is not time-nuts class, but
<100ppm should always be possible and with a bit of tuning, you can get
rid of that as well.

			Attila Kinali

-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin



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