[time-nuts] Testing frequency using NTP Bruce GPS ps

[Didier Juges]

I suspect another reason is that even if it were adjusted, a user's
individual standard would still deviate from the NIST average standard, and
the drift would have to be accounted for anyhow, so what's the point of
attempting to mess with it and take the risk of loosing the data accumulated
so far? (the fact of readjusting a standard, if such adjustment is even
possible, invalidates much of the data collected up to that point.)

Didier KO4BB

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of WB6BNQ
> Sent: Friday, October 03, 2008 10:43 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Testing frequency using NTP Bruce GPS ps
> 
> Mike Monett wrote:
> 
> > > For more detail see:
> >
> >   >  http://tf.nist.gov/timefreq/service/fms.htm
> >
> >   Thanks very  much  for the link. It is curious  they  
> don't  seem to
> >   spend much  effort on correcting the user's  frequency  
> errors. They
> >   just want to report how much they are off.
> >
> >   Why is that? You'd think they would perform a more  
> valuable service
> >   by applying  advanced techniques to adjust the  user's  
> equipment to
> >   minimize the  error, then report and certify the  actual  
> result. Is
> >   there some  reason   they   want   to   leave  the  
> user's equipment
> >   free-running?
> >
> 
> Mike,
> 
> One of the worst perturbations is that of man himself.  
> Unless one is highly knowledgeable of the effect of an 
> adjustment, usually the act of the adjustment is worst then 
> if it had been left alone.
> 
> In the world of the "Primary masters," they do not make 
> adjustments, only compare differences and then report those 
> differences.  Typically, the standards that are inter 
> compared are of such high quality construction that 
> adjustment is neither possible nor wanted.
> 
> For inter comparisons, a device of known quality is measured 
> before it starts its journey around the labs, of course it is 
> measured at each lab and then upon return is measured again 
> at the lab where it all started.  No human adjustment is ever 
> performed.  This way mostly just environmental factors 
> influence the portable reference device and much of that can 
> be mitigated with careful record keeping during its trip.
> 
> In the case of the "FMS" you mentioned, the only difference 
> is the devices being compared are not being moved.  The same 
> methodology still applies however.
> 
> Bill....WB6BNQ
> 
> 
> 
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