[ntp:questions] Sure GPS - PPS not working

Chris North chris at invalid.comt
Sun Dec 8 16:36:31 UTC 2013


Most of the discussion here is way above my head, but I'm hoping somebody 
will be able to help me.

I have a Sure GPS board, modified according to David Taylor's plan, 
connected to a Windows 7 PC by USB (for power only) and by serial null-modem 
cable to COM1 on a PCI serial card.

I am running ntpd 4.2.7p401 and have installed the signed serialpps.sys 
(14.May.2012 16:08) in place of the standard serial.sys driver. I have also 
installed the serialpps-ppsapi-provider.dll with a suitable value for the 
PPSAPI_DLLS environment variable.

When I first set this up a year or more ago, I got the GPS_NMEA and PPS 
entries displayed in the output from ntpq. However, I have just realised 
that PPS is no longer there. NTP is still giving reasonable accuracy - 
adequate for my needs - but I'd still like to get PPS working again.

I have also tried the same setup on my alternative boot into Windows 8.1 and 
the result is the same. And I have tried rolling back to earlier versions of 
ntpd and the serial driver (putting the PC into test mode for unsigned 
drivers).

Here is the event log showing the startup of NTP (newest item at the top) 
The first and second items from the top appear to show a problem.

Level       Date and Time       Source Event Task Category
Information 08/12/2013 15:37:38 NTP    3     None 127.127.22.1 local addr 
127.0.0.1 -> <null>
Error       08/12/2013 15:37:38 NTP    1     None refclock_ppsapi: 
time_pps_create: Exec format error
Information 08/12/2013 15:37:38 NTP    3     None Listen normally on 6 Local 
Area Connection* 12 [fe80::2483:3039:3f57:fef5%12]:123
Information 08/12/2013 15:37:38 NTP    3     None Listen normally on 5 Local 
Area Connection* 12 [2001:0:5ef5:79fb:2483:3039:3f57:fef5]:123
Information 08/12/2013 15:37:38 NTP    3     None Listen normally on 4 
Loopback Pseudo-Interface 1 127.0.0.1:123
Information 08/12/2013 15:37:38 NTP    3     None Listen normally on 3 
Loopback Pseudo-Interface 1 [::1]:123
Information 08/12/2013 15:37:38 NTP    3     None Listen normally on 2 Local 
Area Connection 192.168.1.10:123
Information 08/12/2013 15:37:38 NTP    3     None Listen and drop on 1 
v6wildcard [::]:123
Information 08/12/2013 15:37:38 NTP    3     None Listen and drop on 0 
v4wildcard 0.0.0.0:123
Information 08/12/2013 15:37:38 NTP    3     None proto: precision = 0.400 
usec (-21)

Here is the output from ntpq -p after a decent wait:

     remote           refid      st t when poll reach   delay   offset 
jitter
==============================================================================
*GPS_NMEA(1)     .GPS.            0 l    5    8  377    0.000   -0.036 
0.074
-109.169.89.48   193.79.237.14    2 u   28   64  377   22.674   -4.448 
0.253
+betelgeuse.retr 158.43.192.66    2 u   15   64  377   22.621   -2.651 
0.275
+ntp2.websters-c 193.62.22.82     2 u    -   64  377   25.693   -3.363 
5.207

and this is my ntp.conf file:

driftfile "F:\NTP\etc\ntp.drift"
# PPS - serialpps.sys
server 127.127.22.1 minpoll 3
# NMEA serial port, 16 = 9600 baud, 2 = $GPGGA
server 127.127.20.1 minpoll 3 mode 18 prefer
server 0.uk.pool.ntp.org maxpoll 8 iburst
server 1.uk.pool.ntp.org maxpoll 8 iburst
server 2.uk.pool.ntp.org maxpoll 8 iburst

Can anybody suggest anything useful, please?



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