All the GPS receivers that I have tested get the time message out within a second (either before or after depending upon the model) of the 1PPS pulse... except the Jupiter receivers. For those, the last byte of the time messages arrives 1.25 seconds after the 1PPS pulse. This might cause some problems if the NTP software is not aware of this "feature" of the Jupiter receivers. --------------- > I think the Jupiter has a jitter of around 15ns, not sure what the Jupiter-T specs but I believe 10-20ns.