[ntp:questions] help with setting up NTP on windows with a USB GPS

David J Taylor david-taylor at blueyonder.not-this-bit.nor-this-part.co.uk.invalid
Fri Nov 27 06:45:00 UTC 2009


"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 
another PC running a different OS (with all the associated extra learning) 
just so that accuracy could be improved from scores of microseconds to 
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.

Cheers,
David 




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