Yo All! I have some solid results on minpoll=maxpoll=1. That gives a poll time of 2 seconds. When minpoll=maxpoll=0 works Ill be testing that. UNtil thne I'll be testing other values.
First, the good news. On a Raspberry Pi 3B, with Uputronics hat,
minpoll=maxpoll=1 is much better than minpoll=maxpoll=6 (64s).
At poll=64:
Local Clock Freq Offset: 90% 1.4ppm, Jitter 90% 3.3 us
Local Stability 90%: 2.2 ppt
PPS Offset 90% 68us, Jitter 90% 9.7 us
At poll=2:
Local Clock Freq Offset: 90% 1.1ppm, Jitter 90% 0.43 us
Local Stability 90%: 2.3 ppt
PPS Offset 90% 1.6us, Jitter 90% 0.34 us
See attached pi3-local-offset.png. Before 18:25 12 Sep 2016 UTC is poll=64s
after is poll=2. Pretty nice, a very good improvement in time, for a slight
decrease in frequency. And NTP is all about time, right?
Now the bad news. On a quad XEON, with an MR-350P serial GPS:
At poll=64
Local Clock Freq Offset: 90% 570ppb, Jitter 90% 10.2 us
Local Stability 90%: 1.2 ppt
PPS Offset 90% 34.2us, Jitter 90% 16.3 us
At poll=2
Local Clock Freq Offset: 90% 495ppb, Jitter 90% 16.9 us
Local Stability 90%: 27.7 ppt
PPS Offset 90% 39.0us, Jitter 90% 26.7 us
See attached spidey-local-offset.png. Before 18:10 12 Sep 2016 UTC is poll=64s
after is poll=2. That went really, really badly...
So, the answer to the best poll? It depends...
RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com Tel:+1 541 382 8588
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