[ntp:questions] using both a PPS source and a HBG (dcf-77-like) timesource?
Folkert van Heusden
folkert at vanheusden.com
Mon Jan 14 16:21:29 UTC 2008
> > day, but I think that was for long distances, bouncing off the
> > ionosphere which changed height at night. I'd expect it to be
> > pretty stable if you are close to the transmitter - ground wave.
>
> HBG is in Switzerland if I remember correctly, and from your post, you are
> in Netherlands,
correct
> so you can estimate propagation delay. However, I don't see
> why you would want to use an LF reference of lesser accuracy and estimated
> delay when you can use GPS.
> Just a thought.
Well if I remember correctly someone said to me once that the
time-string returned by cheap gps device (like my garmin 18 lvc)
sometimes is a bit off while its PPS signal is fine.
Currently I'm syncing against NMEA/PPS and seeing quiet a big offset:
remote refid st t when poll reach delay offset jitter
==============================================================================
xGPS_NMEA(0) .GPS. 0 l 7 16 377 0.000 -185.08 1.001 <---
PPS(0) .PPS. 0 l - 16 0 0.000 0.000 0.001 <---
-muur.intranet.v .DCFa. 1 u 5 64 77 0.072 -9.207 0.023
-thegateap.intra .SHM. 1 u 46 64 37 0.873 0.931 0.045
SHM(0) .SHM0. 2 l - 64 0 0.000 0.000 0.001
SHM(1) .SHM1. 2 l - 64 0 0.000 0.000 0.001
SHM(2) .SHM2. 2 l - 64 0 0.000 0.000 0.001
SHM(3) .SHM3. 2 l - 64 0 0.000 0.000 0.001
NTP.MCAST.NET .MCST. 16 u - 64 0 0.000 0.000 0.001
192.168.64.0 .BCST. 16 u - 64 0 0.000 0.000 0.001
-auth1.xs4all.nl 194.109.22.19 3 u 48 64 77 7.945 1.514 1.158
-auth2.xs4all.nl 193.67.79.202 2 u 46 64 77 9.450 -0.893 0.713
+ntp1.nl.uu.net .GPS. 1 u 45 64 77 13.693 0.173 9.097
*chime2.surfnet. .GPS. 1 u 111 64 76 12.262 0.387 1.092
-superboer12.stu 193.79.237.14 2 u 45 64 77 13.012 4.401 2.248
+ntp.networking4 193.190.230.65 2 u 46 64 77 9.242 0.444 0.494
+mailer.zylom.co 193.190.230.65 2 u 44 64 77 9.040 0.430 0.538
-aivd.xelerance. 193.0.0.228 2 u 41 64 77 8.881 -0.610 3.154
Folkert van Heusden
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