On Tue, Dec 11, 2012 at 8:00 PM, David J Taylor <david-tay...@blueyonder.co.uk> wrote: > From: Gabs Ricalde > [] > > David, > > 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? > > > Cheers, > David > -- > SatSignal Software - Quality software written to your requirements > Web: http://www.satsignal.eu > Email: david-tay...@blueyonder.co.uk >
I'm not sure about the jammer but I'm running a timing receiver in position hold several floors up, I haven't seen dropouts like this. ntpd is running with a "noselect" NMEA source since I'm having problems with ntpd marking the PPS and NMEA as falsetickers. The startup sequence for the server is this: * run ntpd -g -q with NMEA enabled * run chronyd for 3 minutes to set the time and frequency offset * copy the current frequency to ntpd's drift file, then run ntpd with NMEA disabled This hack seems to work everytime with ntpd ready in less than 4 minutes after turning on. I just hope nothing would happen that changes the time. I have seen 0.2 us spikes every hour from some unknown task but the larger spikes are rare. Another device running the same OpenWrt firmware but with a timing receiver has only the small periodic spikes. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.