[ntp:questions] Too much offset from GPS?
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Mar 7 13:56:50 UTC 2008
chowalit.lab Chowalit Lab Linux wrote:
> Dear all
> I have problem with my stratum1 box. My box include: freebsd
> 5.2-RELEASE without PPS , ntp-4.2.0_1, Intel Pentium III, 40 G IDE,
> Germin GPSmap60 , connect with serial com. In GPSmap60 set as NMEA.
> Freebsd box can get NMEA input string. My configuration of ntp.conf
> like this:
>
> server 127.127.20.0 mode 1 prefer minpoll 4
> server 127.127.1.0 minpoll 5
>
> server 69.25.96.14 minpoll 6
> server 192.43.244.18 minpoll 6
> server us.pool.ntp.org minpoll 6
> server 203.185.69.60 minpoll 6
> server 122.154.11.67 minpoll 6
>
>
> logfile /var/log/ntp
> logconfig =all
> driftfile /var/log/ntp.drift
>
> It's look OK. After I start my ntp. And I try to check with "ntpq
> -p", result like this
>
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> *GPS_NMEA(0) .GPS. 0 l - 16 3 0.000 -7.127 7.982
> LOCAL(0) 73.78.73.84 5 l 22 32 1 0.000 0.000 0.002
> time.symmetrico .GPS. 1 u 21 64 1 248.084 167.016 0.002
> time.nist.gov .ACTS. 1 u 20 64 1 273.165 156.541 0.002
> andromeda.cs.pu .CDMA. 1 u 19 64 1 295.742 157.582 0.002
> 203.185.69.60 .PPS. 1 u 18 64 1 270.912 292.165 0.002
> 122.154.11.67 .INIT. 16 u - 64 0 0.000 0.000 4000.00
>
>
> My GPS have offset lower than other stratum 1 server ?? .......
> Please help me.
>
>
> Thanks you
> Chowalit
The delay values shown above suggest that you have chosen servers
located many thousand miles away from your location! Since the
potential error in transmitting time from server to client is one half
of the round trip delay these would appear to be the worst possible
choices unless they are the only available servers!
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