[time-nuts] PPS offset between GPS receivers

David J Taylor david-taylor at blueyonder.co.uk
Tue Dec 11 12:00:20 UTC 2012

From: Gabs Ricalde

I forgot to thank you for your helpful site and NTP plotter.

I have the antenna outside with a 180 degree view of the sky, outages
should be rare. Looking at the loopstats, the outage during the 4 us
jump is about 12 seconds. This is a test server, I only have the LOCAL
and PPS refclocks configured so during the outage the clock just
flywheels. I agree these cheap GPS receivers are more than enough for a
stratum 1 NTP server.

How about a 10 channel TIC? I'm sure someone could suggest a way to do
it, probably several PICTIC II's?

Agreed, that if your antenna has a good view of the sky you should not be 
seeing these drop-outs, at least not on a regular basis.  There are 
atmospheric conditions which will affect the GPS signals, though, but they 
should be rare.  No chance you get a trucker with a GPS jammer driving by at 
the problem times, I suppose?

You say LOCAL and PPS - no "seconds" reference such as GPS/NMEA?

You might also want to check what's happening on the box at the time of the 
jump.  If it's regular, perhaps some scheduled task is the cause?

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 

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