On Sat, Mar 24, 2012 at 3:34 PM, Kenyon Ralph <ken...@kenyonralph.com> wrote: > I'm trying to figure out why my FreeBSD 9.0-STABLE system with a > Garmin GPS 18x LVC and ntpd 4.2.7p255 has a consistent -2 ms to -4 ms
My guess is that your GPS is correct and the internet servers are running a positive offset. I think NTP figures the travel time from a pool server to you is one half the roundtrip time. But I'm still confused because you have enough servers that I'd think that effect would average out. But on the other hand all of them share the same "last mile" of wire. The only way to test the GPS is with some other GPSes. Don't use NTP to test a GPS. Compare the PPS from each directly with a counter, a digital scope something you rig up on a breadboard with flip-flops or whatever you have. -- Chris Albertson Redondo Beach, California _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
