[ntp:questions] NTP Performance on WINNT

David J Taylor david-taylor at blueyonder.not-this-part.nor-this.co.uk.invalid
Mon Jul 20 16:06:42 UTC 2009

Richard B. Gilbert wrote:
> Assuming a GPS *TIMING* receiver, and that it can be installed with
> the antenna having a good view of MOST of the sky, you can expect
> results that are *almost* as good as the atomic clocks on board the
> satellites!
> You do need to run a "site survey" to establish your location as
> exactly as possible!  Once your location is known, the calculation of
> the "speed of light delay from your selected satellite to you can be
> done quickly and easily.

I didn't have such difficulties when using today's sensitive GPS devices - 
e.g. GPS 18x LVC:


Having a view of, say, a 180-degree arc of southern sky is probably good 
enough.  I have mine indoors, sitting on top of a PC on the top floor of 
my building.  No separate antenna.  The earlier GPS 18 LVC sits on the 
roof.  The GPS determines its location all by itself - no site survey 
required.  Microsecond accuracy.

Of course, if you are looking at a basement located or tempest-spec server 
room, using GPS becomes rather more difficult!


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