[time-nuts] Traceability after loss of LORAN and WWVB
magnus at rubidium.dyndns.org
Sat Jun 1 13:43:30 EDT 2013
On 06/01/2013 07:18 PM, Bob Camp wrote:
> On Jun 1, 2013, at 11:40 AM, Magnus Danielson<magnus at rubidium.dyndns.org> wrote:
>> On 06/01/2013 04:54 PM, Bob Camp wrote:
>>> At least the way I read the pdf's NIST seems to believe that GPS is legally traceable to NIST. It is the same "measure and then look up the data" sort of thing that LORAN used to be. Took a while to read through them all…
>> However, just taking time from GPS does not achieve NIST traceability.
>> The NIST folks will point it out too.
>> You can achieve NIST traceability (or to any other NIH) if you do a whole bunch of things _right_ and in accordance with relevant standards. Few do.
> In the context of the original post - exactly the same was true of LORAN. To actually achieve traceability you needed to do this and that once you had your "observations". In reality the same is true of WWVB and WWV. None of them achieve traceability in the strict sense simply from the observation of their frequency or time.
I agree fully, and could have added that point to my post, but I wanted
to keep it short.
What I was saying is that many confuse "adjust to" with "traceable to",
which is quite different. Traceability does not even require any form of
adjustment. You can have a clock being off and running at a different
rate, but with calibration these phase and frequency offsets can be
compensated out and a proper reading be given when measurement is
combined with calibration valules.
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