> This agrees with what Kasper Pedersen wrote earlier: >> 3.10 starts transmitting 350ms .. 480ms after PPS >> 3.30 starts transmitting 920ms .. 1220ms (!) after PPS >> 3.50 starts transmitting 700ms .. 1220ms (!) after PPS Folks, With some help from Hal Murray who knows more of NTP than I do, we have worked round this problem as described here: http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm#gps-18x The basic steps were: - make the GPX18x LVC "noselect" so that NTP would not use it - enable the peerstats to measure where NTP thought the 18x end of message occurred - analyse the peerstats file to determine the apparent offset (which was -1.000 seconds, as it happened) - add that offset (as +1.000 seconds) to the fudge time2 value for the 18x in the ntp.conf - restart NTP I hope that helps someone. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-taylor@blueyonder.co.uk