[ntp:questions] Re: Naval Observatory Master Clock

roy roy at suespammers.org
Tue Jul 12 04:04:22 UTC 2005


David M. Alexander wrote:
> I plan on using it to calibrate timers for work.  My device used to
> calibrate the timers must be traceable to a NIST standard.

If the time "must be traceable to a NIST standard" then you probably
should read the NIST documentation on traceability.  A good starting
point is http://ts.nist.gov/traceability/

> Right now I have
> to call a long distance number and listen for 1 minute, then call again at
> 15, 30 minutes and again at 24 hours.

This is certainly a defined measurement process, which is required to
support a claim of traceability.  But if I were your auditor, I would
be concerned that it doesn't really provide good documentation of the
uncertainty in your measurement process.  However, if your
synchonization requirement is only to be with +/- 5 seconds of
UTC(NIST), then this procedure might suffice.

> Was thinking if I could just use a
> function or a macro in excel that would get the time in UTC, GMT or Zulu I
> would have to call.  The spreadsheet could do the calculations to see if the
> timers met the requirements.  I have been to  web sites that displays UTC so
> figured that there must be a way to get it and place it in a cell.
>
> The reason I would like to place the time in a spreadsheet is so I can
> create a certification for audit purposes.

The spreadsheet can probably create a very pretty certificate.
However, I agree with Danny -- the time value in a spreadsheet cell
isn't traceable to anything.

Enjoy,


roy
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>
>
> "Danny Mayer" <mayer at gis.net> wrote in message
> news:42D184A4.9080603 at gis.net...
> > David M. Alexander wrote:
> >> Is there a simple way to download the time from this site or any other
> >> site and place it in an excel spreadsheet? I can't use the computer time
> >> as it isn't traceable to NIST.
> >
> > Apart from the question about why you want it in a spreadsheet, what makes
> > it so important to be traceable to NIST, and even if it is, what you have
> > in the spreadsheet isn't traceable to anything, let alone NIST.
> >
> > Danny
> >
> > _______________________________________________
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> > questions at lists.ntp.isc.org
> > https://lists.ntp.isc.org/mailman/listinfo/questions
> >




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