[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
Tue Dec 1 14:13:24 UTC 2009


"Dave Baxter" <g8kbv at nospam.uko2.co.uk> wrote in message 
news:MPG.257f313bfbd49ce989683 at news.demon.co.uk...
[]
> Is there a blow by blow (with screenshots?) description as to how to put
> all this together anywhere?   David Taylor's site gets close, but I
> suffer "informaion overload" after a while.   (The Grey cell version of
> a buffer overun I think!)
[]
> Comments, suggestions welcome.
>
> Regards.   You can all stop laughing now!
>
> Dave Baxter.

Dave,

I would not worry about adding the special serialpps.sys, at least not 
initially.  Why?  If you take a look at the offset graph here:

  http://www.satsignal.eu/ntp/2009-05-17-Feenix_offset.png

I would challenge you to see which "half" of it was with the kernel-mode 
serialpps.sys and which was with the standard driver.  Yes, it's more 
obvious if you look at the jitter graph here:

  http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html#PPSAPI_DLLS

but even then the averaged jitter only changes from just over three to 
just over two microseconds - to me negligible in comparison with the ~150 
microseconds of offset.  Temperature appears to be the main enemy I'm 
facing.

Just concentrate on getting the basic GPS/PPS working.

73,
David - GM8ARV 




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