Hi Dave! Thanks for your support!
2011/8/2 Dave Hart <h...@ntp.org>: > Actually both were seeing the PPS signal from the start, or else you > would not have been seeing offsets in the low microseconds on both. > ntpd 4.2.4 never uses the 'o' tally code, PPS or not, you will see * > for the controlling peer. With 4.2.6, you will see tally code 'o' for > the controlling PPS, and you can also see '*' at the same time on > another refclock that is "numbering the seconds" for the PPS, though > not in your original configuration where a single NMEA driver is both > numbering the seconds and providing the PPS, for that configuration > you will see 'o' on NMEA once the PPS is engaged. Understood. > You do not need to configure a separate PPS driver, and are probably > best off to not. If you do, change the NMEA flag1 to 0 so it will not > also attempt to process the PPS. Will use only the NMEA driver then. > Note the 'o' tally only appears when ntpd is talking directly to the > PPSAPI interface. A common configuration on Linux systems puts gpsd > in the middle, and provides the GPS and PPS information via a shared > memory driver to ntpd. In that case, the selected refclock never will > show 'o' regardless of ntpd version, because ntpd is not using PPSAPI. > The gpsd approach has the upside of letting you use the GPS from > other programs at the same time as ntpd, and also does not require > PPSAPI support, which mainstream Linux hasn't had until very recently. > The downside is the PPS is being timestamped in > preemptively-scheduled gpsd code, rather than in an interrupt handler, > so the PPS timestamps are noisier with gpsd compared to direct PPSAPI > from ntpd. I am using FreeBSD. This is a pair of stratum 1 servers for a mid-size LAN. I am considering opening the NTP port to the World for one of the servers. I am thinking about security issues this might involve. BTW, I am using a Garmin 18 LVC and a Sure GPS board. The Sure is great. It is working on indors with exterior blinds completely closed and it is picking up 8-9 satellites regularly. I was looking at the Trimble Resolution T to try it out. Can you suggest a cheap and easy to assemble unit that has a detachable antenna like the Sure? Thanks! Cheers, Miguel _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
