[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
Wed Dec 2 20:14:09 UTC 2009

> David,
> I got this going and everything is working well. However, comparing
> NTP time to an IRIG board time with a GPS antenna, I see a difference
> of 100ms. Not sure where this came from.
> Jack

Good question!  What is the pulse-length of your GPS PPS, and to which 
edge is NTP syncing?  There's a setting in NTP you can tweak.  I think 
that mine is probably right as I see only a few milliseconds of offset 
compared to Internet servers.  I have the DCD line directly connected to 
the output from the GPS 18 LVC with no inverter in the path.


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