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Groups > comp.protocols.time.ntp > #164179

Re: Using ntpd with -g option

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David Taylor via questions Mailing List <questions@lists.ntp.org> wrote:
> On 28/03/2025 21:54, Jim Pennino wrote:
>> On Fri, Mar 28, 2025 at 04:37:09PM -0500, Steven Sommars wrote:
>>> Caution advised.  When I monitored a FC-NTP-Mini 1.5 years ago the
>>> timestamp resolution was only 1 msec.
>>> Additionally once in 2000 NTP responses the time stamp was in error by 1
>>> second (top of the second problem).
>>>
>>> Things may have improved since then.
>>>
>>
>> I have been running a pair of them for 995 days, do extensive graphing
>> of all the ntp servers here, and have noticed nothing strange.
>>
>>       remote           refid      st t when poll reach   delay   offset  jitter
>> ==============================================================================
>> *127.127.28.0    .SHM.            0 l    5   16  377    0.000   +3.562   2.434
>> -192.168.0.21    .PPS.            1 u   19   64  377    1.326   -2.751   1.908
>> +192.168.0.100   .PPS.            1 u   48   64  377    0.077   -3.755   0.878
>> +192.168.0.101   .PPS.            1 u   56   64  377    1.150   -3.295   1.724
>> -192.168.0.185   .PPS.            1 u    2   64  377    1.120   -1.329   0.890
>>
>>
>> The SHM server is a ublox USB GNSS.
>>
>> The .21 server is a Raspberry Pi with a late model GNSS HAT.
>>
>> The .100 and .101 servers are FC-NTP-Minis.
>>
>> The .185 server is a precision steared, temperature controlled
>> oscillator box with a GNSS receiver and a specified PPS accurace of +/-
>> 1 nanosecond.
>>
>>
> 
> Jim,
> 
> May I suggest making comparisons on a device with (working) PPS synchronisation.
>  This should make the jitter and offset values more consistent.

     remote           refid      st t when poll reach   delay   offset   jitter
===============================================================================
*NMEA(0)         .GPS.            0 l    2   16  377   0.0000  -5.0594   0.9532
oPPS(0)          .PPS.            0 l    1   16  377   0.0000   0.0010   0.0007
+192.168.0.100   .PPS.            1 u   20   64  377   0.1318  -2.5307   0.0226
+192.168.0.101   .PPS.            1 u   25   64  377   0.1462  -2.5510   0.0241

OK, there you go.

> 
> As an example, here I'm looking at a Win-11 PC (Oslo) with PPS sync for its NTP,
> viewing its remote servers:
> 
> C:\Users\win-8>ntpq -pn oslo
>      remote           refid      st t when poll reach   delay   offset  jitter
> ==============================================================================
>  127.127.20.1    .NMEA.           0 l    -   16    0    0.000   +0.000   0.000
> o127.127.22.1    .uPPS.           0 l   14   16  377    0.000   +0.033   0.002
> *192.168.0.20    .GPS.            1 u   21   32  377    0.462   -0.106   0.028
> +192.168.0.3     .PPS.            1 u    6   32  377    0.463   -0.142   0.030
> +192.168.0.71    .PPS.            1 u    9   32  377    0.693   -0.139   0.029

I note that you are not processing NMEA data at all. You might want to
fix that.

> 
> .20 - LeoNTP (old version)
> .3 - Linux box (x86) with PPS feed
> .71 - Raspberry Pi with PPS feed
> 
> The delays are higher than I would wish, but likely due to multiple switches in
> the paths and some parts be just 100 Mbps links
> 
> Cheers,
> David
> 
> --
> SatSignal Software - Quality software for you
> Web: https://www.satsignal.eu
> Email: davidtaylor@writeme.com
> BlueSky: @gm8arv.bsky.social, Twitter: @gm8arv
> 

-- 
penninojim@yahoo.com

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Using ntpd with -g option "rcheaito via questions Mailing List" <questions@lists.ntp.org> - 2025-03-27 22:43 +0000
  Re: Using ntpd with -g option "Harlan Stenn via questions Mailing List" <questions@lists.ntp.org> - 2025-03-28 00:58 +0000
    Re: Re: Using ntpd with -g option "rcheaito via questions Mailing List" <questions@lists.ntp.org> - 2025-03-28 11:48 +0000
      Re: Using ntpd with -g option David Woolley <david@ex.djwhome.demon.invalid> - 2025-03-28 14:39 +0000
      Re: Using ntpd with -g option Terje Mathisen <terje.mathisen@tmsw.no> - 2025-03-28 15:51 +0100
        Re: Using ntpd with -g option William Unruh <unruh@invalid.ca> - 2025-03-28 15:40 +0000
          Re: Using ntpd with -g option Jim Pennino <jimp@gonzo.specsol.net> - 2025-03-28 12:07 -0700
        Re: Using ntpd with -g option "David Taylor via questions Mailing List" <questions@lists.ntp.org> - 2025-03-29 08:43 +0000
          Re: Using ntpd with -g option Jim Pennino <jimp@gonzo.specsol.net> - 2025-03-29 07:47 -0700
            Re: Using ntpd with -g option "David Taylor via questions Mailing List" <questions@lists.ntp.org> - 2025-03-30 18:18 +0000
              Re: Using ntpd with -g option Jim Pennino <jimp@gonzo.specsol.net> - 2025-03-30 12:04 -0700
    Re: Using ntpd with -g option "Jim Pennino" <jimp@gonzo.specsol.net> - 2025-03-28 22:58 +0000
    Re: Using ntpd with -g option "David Taylor via questions Mailing List" <questions@lists.ntp.org> - 2025-03-30 08:13 +0000
      Re: Using ntpd with -g option Jim Pennino <jimp@gonzo.specsol.net> - 2025-03-30 07:27 -0700

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