[ntp:questions] NMEA ref.clock better than my ISP's timeserver?

Unruh unruh-spam at physics.ubc.ca
Wed May 27 20:45:51 UTC 2009


pisteoff at start.no writes:

>On 27 Mai, 21:43, Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
>> piste... at start.no wrote:
>> > After first trying the Haicom HI-204III claiming to have PPS in the
>> > manual without really having it, I bought a Garmin 18x LVC and
>> > connected it to the onboard COM-port (COM1) on my Asus M3N78 PRO
>>
>> Very good!
>>
>> (Using USB power I assume?)

>I was thinking about USB-power, but ended up with keyboard-power since
>a PS2 connector was easiest to find when soldering the cable. :)

>Actually the Garmin 18x LVC is quite expensive here in Norway? Seems
>like it's quite a lot cheaper abroad, but with tax and postage I don't
>think it's any cheaper to order one unit from US or somewhere...

How much is "quite expensive" It should be about US$100.


>> > mainboard. The Haicom is residing on a USB serial adapter (COM6) to
>> > check how stable the offset is.
>>
>> > Running ntp4.2.5p175-win-x86-bin configured with a couple of
>>
>> Windows...

>Windows XP SP3 running on an AMD Athlon Dual Core 4850e (2,5G0Hz) with
>4GB PC8500 RAM. Quite overkill for a pure NTP-server I suppose, but I
>have lot's of other things I like to test on this computer!

No, serioius underkill. windows is NOT what you want to use to keep
time. The time keeping functions of windows are not up to the job of
keeping accurate time. Operating system limitations, not hardware. 



>> > timesources it seems like my ISP's NTP-server gets "disqualified".
>> > Before setting up my own ref.clock I used to have ntp.online.no as my
>> > "favorite NTP-server" thinking it would be the best / most local
>> > server, but now I might offer them to use me as a clock-source? ;)
>>
>> > Anyone wishing to see on their own, might check with ntpq
>> > solbakken.dyndns.org =A0 What kind of accuracy is expectable with a NME=
>A
>> > GPS with PPS connected to the DCD-line of the serial port? It's not
>> > that I have any special need for extreme accuracy, but I suppose it's
>> > allright having the most accurate clock in the neighborhood. :)
>>
>> Hei, hei!
>>
>> If your neighborhood is Oslo, I probably have you beat, with 6-8
>> GPS-quality PPS sources, including 5 Oncore timing receivers, all
>> connected to FreeBSD servers with PPS support. :-)

>I'm on Gj=F8vik, so until the opposite is proved I still think I have
>got the most accurate clock in the neighborhood :)




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