[time-nuts] A question about GPS pps quality.
robert at kudra.com
Thu Jul 26 11:38:53 EDT 2007
I've been a time-nut for years, and now I have a mailing list.
I've wanted a personal Stratum-1 server for a long time, and I'm still
trying to figure how to get there. I've got three GPS devices around,
all of which promise 1us pulse accuracy. I thought the simplest thing
would be to use the TAPR fatpps gadget to interface with a FreeBSD
machine. I've got three Garmin devices to choose from: A GPS-20, a
GPS-25, and an 18LVC. The 20 and 25 are old and otherwise useless, so
they are the first choices.
I don't have much of a budget, as I'm a grad student (EE).
So the question is:
1. If I interface one of these to my closet-based server, do I really
have a Stratum-1 source? 1us accuracy doesn't sound all that great, but
I'm nut so sure that the server can take advantage of a pulse with
2. Would I get significantly better performance if I shelled out $75
for one of the new trimble timing GPS modules, or found an old oncore
timing module on ebay?
I know that the oscillator on my old AMD based UNIX machine isn't all
that great, but I'll leave that question for another time.
Robert Sexton - robert at kudra.com, Cincinnati OH, USA
You should never wear your best trousers when you go out to fight for
freedom and liberty. -- Henrik Ibsen
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