[ntp:questions] ntp-dev: PPS is a falseticker?

Paul tik-tok at bodosom.net
Sun Jun 15 14:37:32 UTC 2014


On Sun, Jun 15, 2014 at 2:29 AM, Rob <nomail at example.com> wrote:

> Maybe you can help me?   The following is in the documentation:



This works using 4.2.7p440.  I don't expect it's too version specific.
It's the simplest solution.  Season start-up to taste.

root at bbb2# ntpq -p
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
oPPS(0)          .GPPS.           0 l    6    8  377    0.000    0.015
0.007
*LOCAL(0)        .LOCL.          12 l   46    8   40    0.000    0.000
0.004

root at bbb2# ntpq -p nub
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
oPPS(0)          .GPPS.           0 l    6    8  377    0.000    0.000
0.002
*ntpa            .GPPS.           1 s    5    8  376    0.176    0.007
0.010
+black           .GPPS.           1 s    1    8  377    0.167   -0.002
0.003
+rPi1            .GPPS.           1 s    5    8  376    0.203    0.059
0.057
+ntp1            .GPS.            1 u    6    8  377    0.666    0.129
0.185
+bbb2            .GPPS.           1 u    5    8  377    0.390   -0.081
0.008
 t3500-6         .GPPS.           1 u   33   64  377   36.032    2.172
0.358

Of course the better solution is to get a more capable GPSDO.  I recommend
a Fury which shows that NMEA can deliver low jitter results and will
provide many days of hold-over.

root at ntpa# ntpq -p
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
oPPS(0)          .GPPS.           0 l    6    8  377    0.000    0.001
0.002
*GPS_NMEA(0)     .FURY.           0 l    6    8  377    0.000   -0.049
0.013
...

Finally you can rethink your (problem,solution).  For most folks that want
a local stratum 1 I'd suggest getting a Laureline -- [michael.cook at sfr.fr
] (I suspect) reviewed his second generation unit a few days ago.


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