[time-nuts] Msg to N.Z. time nuts

Hal Murray hmurray at megapathdsl.net
Mon May 18 20:49:17 UTC 2009


lists at philpem.me.uk said:
> Interesting that the three receivers with issues were all SiRF III
> based. Do  you know what firmware these were running? 

Nope.  If you know the recipe to find out, I'll ask them.  :)

I just scanned their NMEA documentation and didn't see any way to get it.


> How are you running the comparisons -- comparing against public NTP servers?

The data gets collected on a system without PPS, but it's sitting next to a 
machine that does have PPS from a Z3801A.  So their is some noise on the 
reference time, but not much on the scale of a 100 ms that the SiRF chips 
wander over.


> I'm just curious, there's a pair of Fastrax SiRF III modules that I
> was going  to wire up for testing (and maybe use for a GPSDO), but
> your test results have  planted the seeds of doubt! 

I expect the PPS output is still OK.  It's just that the software is off by 
one in some strange pattern when a leap second is pending.



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