I haven’t used the NTP configuration below for years. I came up with it from some recipe(s) I found online (some commented in the file). The "time2 0.350" was the generally accepted best number for the original Raspberry Pi A/B. I personally have no idea how to tune NTP. I just used what I thought was the best information I could find at the time.
My current NTP server is part of pfSense (FW/Router/NTP/etc., based on FreeBSD-10.3-RELEASE) Their web interface is limited in some of the NTP/PPS/GPS settings you can easily get to. If you make changes outside the web interface, you risk them being overwritten by the web interface. I really need to get a good config nailed down & not touch it. > On May 5, 2016, at 7:12 PM, Gary E. Miller <g...@rellim.com> wrote: > > I use the 28 refclock, you the 20. Regarding 28 ref clock, that is SHM? Why that rather than NMEA (20)? > I think for our purposes time1 and time2 are the same? Basically the > NMEA fudge. > > I use a time1 of 0.480 for my Ultimate GPS HAT. Just about in the > middle of my 30 to 70 milliSec jitter. I don’t remember what the difference is between time1 & time2. I do remember it was for NMEA fudge I just know the documentation I found always had time2 set. > I find a short poll leads to a more unstable result. Have you tried > a longer poll? I’ll look at this on my current configuration. What’s a good way to “tune” my NTP config? What’s a good way to monitor my NTP performance? > Mode 17 is 9600? Up that if you can. Correct, 16 = 9600 & 1 = specified the NMEA sentence to get time from, I think... I’ll look at upping it on my current configuration. I had to limit the statements that came out, so they didn’t run over the second (some periodic (every 5 or 10 seconds) NMEA statements made it take > 1 second for a cycle). > You'll do better if you hand pick some close chimers. There is some > bad shit in the pool, and you may be using something from Singapore > or Bangalore. If you must pool, at least use a US pool. Like: > > server 0.us.pool.ntp.org iburst > server 1.us.pool.ntp.org iburst > server 2.us.pool.ntp.org iburst > server 3.us.pool.ntp.org burst Thanks - I’ll look at this on my current configuration _______________________________________________ devel mailing list devel@ntpsec.org http://lists.ntpsec.org/mailman/listinfo/devel
