Greetings All:
There is a very cheap source of very high stability reference available to
everyone. It is the 1 PPS from almost any second hand OEM level GPS
receiver. I have one here that cost $20 US$, about the size of what we once
called a penny folder of paper matches. I did a little poking around on the
Internet over a year ago and found a chap selling Garmin GPS OEM Model 20
and 25 units complete with the external connector. The unit I have here
runs happily on 5V. The removal of selective availability (SA) last year
means only the 5% of the time basic jitter is left, references are possible
to stabilities in a few parts in 10 - 11th.
Brooks Shera published an excellent article in QST on "disciplining" a
frequency standard to the GPS 1 PPS signal.
see http://www.rt66.com/~shera/index_fs.htm
Hope this might help some find a way to improve stability on LF
Larry
VA3LK
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