Hello People,
I seem to have a timing issue with a HP 58534A smart antenna; the NMEA refclock
is always about half a second out and never gets selected:
[root@NTP /etc/ntp]# ntpq -p
remote refid st t when
poll reach delay offset jitter
==============================================================================
GPS_NMEA(0) .GPS. 0 l 6 16
377 0.000 525.229 0.027
*time.non-stop.c 203.35.x.x 2 u 28 64 377
0.285 1.158 0.312
I have tried this on a win NTP server and a freebsd job. Same result.
I wonder if I could bounce this off you, any insight would be appreciated.
According to the manual:
The first character of the first serial data packet is transmitted 400 ms
(± 2 ms) following the rising edge of a 1PPS pulse.
A date/time stamp for a 1PPS pulse is included in the serial data
packets which are transmitted by the 58534A GPS Timing Antenna
directly before the rising edge of each 1PPS pulse.
In a series of data packets, the date/time stamp is normally the last data
packet in the series.
Please see http://www.non-stop.com.au/sites/users/marks/097-58534-01-iss-1.jpg
for diagram.
The timing looks wrong to me, and I would have thought the sentence should come
on the pulse, not before.
*Is this normal behaviour?
Now, I have just applied fudge 127.127.20.0 time2 -0.5 via ntpdc
After a few seconds:
[root@NTP /etc/ntp]# ntpq -p
remote refid st t when poll
reach delay offset jitter
==============================================================================
GPS_NMEA(0) .GPS. 0 l 4 16
377 0.000 25.272 377.930
*time.non-stop.c 223.252.x.x 2 u 26 128
377 0.299 0.731 0.076
I will monitor for a few hours and post result.
Many thanks,
Mark
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