Posted by
David Woolley (E.L) on
Mar 16, 2009; 8:32am
URL: http://elecraft.85.s1.nabble.com/K3-Time-tp2481285p2484689.html
Julian, G4ILO wrote:
>>
>>
> If you use Windows then the best program for ensuring your computer clock is
> spot on is NTP for Windows which you can get from here:
>
http://www.meinberg.de/english/sw/ntp.htm . I have used it when I received
As this often causes confusion, it is worth pointing out that this is
not something written by Meinberg, but simply the reference
implementation of NTP, which Meinberg have compiled for Windows and to
which they have added an installer. The reference implementation is the
definitive implementation that needs to be produced before an RFC can be
issued. The NTP reference implementation is open source.
> NOAA satellite images and when using WSPR when you need better than one
> second accuracy. This program runs as a service and after it has worked out
> the drift in your computer clock it applies constant millisecond corrections
Technically it applies frequency corrections - NTP uses a PLL - it was
designed by an electronics engineer and ham.
> so it is spot on all the time. The time synchronizer built in to Windows XP
Windows is a poor platform for time and, on most other platforms the
reference implementation gives even better time, although there is some
evidence that another open source implementation, chrony, that uses the
same over the wire formats but a different (linear regression based)
mathematical approach, has better behaviour for start up and temperature
change transients, in real world use. However chrony is only supported
on Linux, and doesn't support local radio reference clocks.
> only syncs the clock once a week which may not be enough on some PCs.
The poll period is configurable, and the Windows 2003 version can be
configured to almost use the proper NTP algorithm. The reference
implementation is still much better, as it uses various tricks to get
round the fact that Windows only reports time to applications with a
10ms resolution, by default, or 1ms with the fastest multi-media timers.
I would generally ignore the non-open source alternatives as many are
very crude and none are better than the reference implementation, or chrony.
--
David Woolley
"The Elecraft list is a forum for the discussion of topics related to
Elecraft products and more general topics related ham radio"
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