[ntp:questions] help with setting up NTP on windows with a USB GPS
unruh-spam at physics.ubc.ca
Sat Nov 28 00:24:42 UTC 2009
"David J Taylor" <david-taylor at blueyonder.not-this-bit.nor-this-part.co.uk.invalid> writes:
>"David Woolley" <david at ex.djwhome.demon.invalid> wrote in message
>news:hen3cv$nit$1 at news.eternal-september.org...
>> jack wrote:
>>> I am trying to setup NTP on Windows XP with a USB GPS at "COM1". I can
>> You are making life difficult. Without PPS, GPS has poor accuracy, and
>> potentially high jitter. USB adds a lot of extra jitter. Windows is
>> not the best platform for time keeping.
>>> I installed the Meinberg NTP server and then overwrote ntpd.exe with
>> Meinberg don't do an NTP server, they do a Windows installer for the
>> reference version of ntpd.
>So in these days of energy economy would your solution be to install
So throw away all your computers. Then all of these problems disappear.
>another PC running a different OS (with all the associated extra learning)
>just so that accuracy could be improved from scores of microseconds to
I think you mean 10s of msec to 1s of microseconds. If you do not need
it, certainly using a separate computer would be overkill. If you need
it, then presumably you have to factor in the costs and figure out how
much you need it.
I would certainly NOT use USB for accuracy. I would certainly not use
Windows for accuracy.
On a windows system, using the net (Ie external servers ) might well be
just as good or better than a usb gps.
>microseconds? Does jack need the greater accuracy? Using USB doesn't
>mean you need to give up PPS - some serial-to-USB converters carry the DCD
>line. Even with USB, even with Windows, fractions of milliseconds are
>achieved as I show on my Web page.
>Whilst I see what you mean, pedantically, Meinberg's installation of
>ntpd.exe works just like any other NTP server, by the way.
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