[time-nuts] GPS receiver time message offsets to 1PPS

Mark Sims holrum at hotmail.com
Mon Jul 25 22:09:41 EDT 2016

Heather will take either time format,  but requests the receiver to send T2 format.

I originally thought the SCPI receivers would be right on time due to my original measurements of their message jitter,  but when I started measureing the actual message arrival times... surprise, surprise, surprise!    I think the issue is due to the fact that they use Motorola receivers and those ramp the time the message comes out (1 msec per second).

The other surprise was the Jupiter-T message is 1.2 seconds after the 1PPS... that's just plain wrong... it reports the correct leap-second offset, but maybe they are off by a second internally?  Maybe premature application of the leap pending?  Maybe it's always just plain wrong?

Attached is a plot of the evil Z3801A in action...   

Those ramps don't make sense to me.  Mine are consistently right on.
Are you using T1 or T2 format?  t1 is the default.  I'm using T2.  (Seems unlikely it would make a difference, but stranger things have happened.)

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