[time-nuts] leontp offset?

[Chris Albertson]

I think the best assumption you can make is to take it at face value.
It looks like leontp is about 10ms "off" from your local time.   One
of you is wrong and at this point there is no way to know who is wrong

But of course you appear to be getting time closer to arbiter

So either arbiter or leontp is wrong.  You don't know which.

I would add five more pool servers to your set of reference clocks and
let it run over night.  Pool servers are good because many people use
them so if there was a problem they would hear about it

In any case you don't have enough reference clocks.  Get some more
diversity, certainly more than two sources

One more thing, just because an NTP server is shown as getting time
from GPS does not mean it is accurate.  They may be using only NMEA
sentences and no PPS in which case a 10ms error would be quite good




On Fri, Oct 14, 2016 at 5:31 PM, gmx tallahassee
<gmx.tallahassee at gmail.com> wrote:
> Hi all,
>
> I'm checking out the leontp ntp time server (leontp.com).  After a week of
> use I am getting the following ntp -q output:
>
> $ ntpq -pn
>      remote           refid      st t when poll reach   delay   offset
> jitter
> ==============================================================================
> *172.17.21.11    .GPS.            1 u   13   16  377    0.137    0.077
> 0.054             <- Arbiter 1084C GPS Clock
> +172.17.21.12    .GPS.            1 u   11   16  377    0.101    0.085
> 0.174             <- Arbiter 1084C GPS Clock
> x172.17.21.233   .GPS.            1 u   11   16  377    0.071    9.760
> 0.061            <- LeoNTP
>
> the offset of the leontp device from the other clocks has consistently been
> in the 9.5 -10.5 range.  since I'm measuring all three sources  from the
> same (EL7) computer, I would expect that the offset of the leontp unit to
> converge to be in the close neighborhood of the offsets of the arbiters.
> It has not converged, instead maintaining the ~10ms offset.
>
> Thoughts?
>
> Thanks.
>
> Details:
>
> 172.17.21.11 is approx 400M away through two Cisco 3750G switches no
> routing.
> 172.17.21.12 is in the same rack as the leoNTP unit and plugged into the
> same 3750G switch
>
> Antenna location for the .12 arbiter and the leontp is on the same rung of
> the same tower.  Tower has clear horizon to horizon view.  cable runs are
> the same (obviously).
>
> I did run with the included puck in my south facing office window (rather
> than the GPS antenna on the tower) for a couple of days when I first got
> the unit.  The offset behaviour was the same.
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-- 

Chris Albertson
Redondo Beach, California