-----BEGIN PGP SIGNED MESSAGE----- Hash: RIPEMD160 Patrick Klos wrote: > In article <[EMAIL PROTECTED]>, > DJ <[EMAIL PROTECTED]> wrote: > >>I have a 4000 GPB ($6000 ?) GPS time source - it works beautifully. >>I then took a $200 etrex hand-held GPS, set it to NMEA mode, plugged in >>into a serial port on a Linux machine, I then did >>ln -fs /dev/ttyS0 /dev/gps0 and configured ntp.conf >> >>server 127.127.1.0 >>fudge 127.127.1.0 stratum 10 >> >>server 127.127.20.0 >> >>I started ntpd and then my linux platform appears as a stratum 1 >>server. However, it seems to have an approx 300mS offset from the 4000 >>GBP GPS time source. > > > What are the chances that one or the other of your time sources is using > the wrong edge of the PPS? 300ms sounds like a reasonable "active" time > for a pulse per second signal. >
The Etrex doesn't have PPS so I suspect it's more a case of the NMEA message not being consistent. If the offset is a constant number and the jitter low then it's just a matter of using a fudge to correct the offset in the NMEA message - however if the jitter is high then the using is pretty much unusable as a refclock. John -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (MingW32) iD8DBQFDWVKeaVyA7PElsKkRA0pKAKDGLamcmybwkr6AYoVQcTzprUTOgwCguBkf 2kmomEbQgUpLZHuX5lU94Xk= =ru5p -----END PGP SIGNATURE----- _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
