[ntp:questions] Odd offset for PPS DCD w/ Garmin GPS 18x LVC

lellis larry.ellis at gmail.com
Tue Mar 22 15:30:56 UTC 2011


On Win XP, I am seeing an odd positive offset of about 128ms on the
Atom driver, relative to other sources:


     remote           refid      st t when poll reach   delay
offset  jitter
==============================================================================
*GPS_NMEA(1)     .GPS.            0 l    6   16  377    0.000
0.373   0.919
xPPS(1)          .PPS.            0 l    5   16  377    0.000
125.447   0.830
-clock.team-cymr 172.16.65.22     2 u   39   64   77   12.989
-41.044  44.960
+ntp.okstate.edu .USNO.           1 u   42   64   77   28.906
-18.762  25.784
+navobs1.wustl.e .GPS.            1 u   38   64   77   19.133
1.819  19.599

Normally, I just use NMEA with fudge, but that was also showing the
odd offset so I removed fudge and added the Atom driver to help debug
this.

(Normally the status shows oPPS(1) but xPPS(1) is seen above for the
obvious reason.

ntpd is Dave Hart release 4.2.7p138;  I have a serialpps-ppsapi-
provider.dll dated 6/6/2009.

Any ideas or recommendations.




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