[time-nuts] Checking Time difference between PCs

David J Taylor david-taylor at blueyonder.co.uk
Fri May 24 01:31:01 EDT 2013

I wonder if anyone has suggestions as to how to check the timing variations
between two PCs that are running windows.

The background to this request is that I am running two instances of the
Weak Signal Program WSJT on the same computer and get variations of +/-0.2
seconds.  It has been suggested that the variations might be caused by the
windows operating system.  As a check on this I am proposing to run two PCs
locked by GPS-18 USB and set by NMEATime which should show the difference on
WSJT.  But is there some program that will show the difference due to the PC
clocks alone? Or perhaps a program that outputs the PC time as a pulse on a
sound card so I can compare these on a CRO.

Regards Rex VK7MO


My NTP plotter program may help with that task:


If you are using a PPS GPS (/not/ a USB version) and install NTP your should 
easily get within a millisecond on Windows PCs, see my results here:


Installing NTP on Windows, and using some GPS/PPS receivers:

David GM8ARV
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 

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