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Re: Time references (UT vs. GPS) Whoa, there!



On Mon, 7 Jul 2003  NX7U wrote:
>I found this interesting...it may be widely known but it wasn't by
>me ;-)
>
><http://www.leapsecond.com/java/gpsclock.htm>
>
>
>Definitions - pulled from the Leapsecond website:
>UTC, Coordinated Universal Time, popularly known as GMT (Greenwich
>Mean Time), or Zulu time. Local time differs from UTC by the number
>of hours of your timezone.
>GPS, Global Positioning System time, is the atomic time scale
>implemented by the atomic clocks in the GPS ground control stations
>and the GPS satellites themselves. GPS time was zero at 0h 6-Jan-
>1980 and since it is not perturbed by leap seconds GPS is now ahead
>of UTC by 13 seconds.

<snip>

To which VE7LDH added:

>I work with systems that are synchronized with GPS, and
>that 13 second difference to UTC is very much part of my
>soul nowadays.

OK, this has been bugging me no end - I simply don't see any 
13-second difference between (a) my receiver hearing WWV over the 
air, (b) an atomic clock that synchs up with WWVB every evening and 
(c) my Garman GPS-12.  There IS NO 13 SECOND DIFFERENCE that I can 
see!

Now, I saw the reference to the 13 second difference on the web page 
that Scott referenced, but I can't find it anywhere else in the 
references I've looked at.  Is this merely another urban legend?

Or, is my GPS unit really 13 seconds slower than it should be?

Anyone care to duplicate or dispute my observation?

73 Wayne N5WD

--
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  R. Wayne Day N5WD Ft Worth,Texas n5wd@charter.net
QRV: IRLP node 3852  146.450smpx PL 100.0 Bedford, TX
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