[ntp:questions] Second attempt at GPS-18 based NTP server

David J Taylor david-taylor at blueyonder.co.uk.invalid
Fri Feb 10 16:25:36 UTC 2012


> Hello Again,
>
> Okay, everyone has said I definitely need to use a custom kernel, and I 
> have now done that, and ntpdc -c kern now reports the following:
>
> pll offset:           -1.091e-06 s
> pll frequency:        -3.196 ppm
> maximum error:        0.019912 s
> estimated error:      1e-06 s
> status:               2107  pll ppsfreq ppstime ppssignal nano
> pll time constant:    7
> precision:            1e-09 s
> frequency tolerance:  496 ppm
> pps frequency:        -3.196 ppm
> pps stability:        0.022 ppm
> pps jitter:           1.261e-06 s
> calibration interval: 128 s
> calibration cycles:   797
> jitter exceeded:      522
> stability exceeded:   0
> calibration errors:   5
>
> Which looks fairly reasonable, as the status line is talking about 
> ppstime and ppssignal. Not sure about 5 calibration errors...
>
> But then I look at ntpq -p and it says this:
>
>     remote           refid      st t when poll reach   delay   offset 
> jitter
> ==============================================================================
> +server1.terrybu 158.43.192.66    2 u   70  128  377    6.356   -0.122 
> 13.187
> -82.113.154.206  193.62.22.82     2 u   70  128  377    5.441   -0.582 
> 13.929
> +gamma.h3x.no    195.234.155.123  3 u    1  128  377    6.066   -0.228 
> 0.660
> *GPS_NMEA(0)     .PPS.            0 l    2   64  377    0.000   -0.001 
> 0.001
>
> I'm fairly sure that there should be a lower case "o" to the left of 
> GPS_NMEA, and there is not.
>
> Am I right to be worried?
>
> Thanks again!
>
> Paul

Paul, I had the same problem about the tally code.  NTP 4.2.4 (as supplied 
with FreeBSD 8) produced a "*" when PPS /was/ in operation.  NTP 4.2.6p5 
produced a "o", as does the current development version - ntpd 4.2.7p255. 
All these as viewed from a remote PC running Windows NTP 4.2.7p241.

Your 2107 status looks good to me.  I also see calibration errors - about 
25 in ten hours since a cold start.

I hope that helps.

Cheers,
David 



More information about the questions mailing list