[time-nuts] Traceability after loss of LORAN and WWVB

Sun Jun 2 11:43:22 EDT 2013

Hi

By the procedures currently being used today, IF you still could use LORAN, it would be no cheaper or easier than GPS. The issue is not GPS versus LORAN, it's that the world of legal traceability has moved forward over the last 50 years. The commonly accepted process of how you do it correctly is different today than it once was. We didn't used to all do ISO-9000 either ….

By the procedures used 50 years ago, you could indeed make a measurement against LORAN. That did not give you a letter from NIST showing that your *measurement* was right. What you got back then was a letter from USNO at the end of the month showing their data on LORAN as radiated. That's 100% identical to the data you click on and download today from the NIST  web site for GPS. It's quicker and easier to do today (the old way) than it ever was in the past. 

Bob

On Jun 1, 2013, at 4:36 PM, Scott McGrath <scmcgrath at gmail.com> wrote:

> The key is the nice letter from NIST proving to the auditors that you followed the procedure.   
> 
> That's the piece that's harder to get today than in the LORAN days unless I am missing something here like a website where you enter your measurements and they certify and send the nice letter back electronically
> 
> The quick process is done by the 'lick-n-stick' quickie-cal shops all over the place
> 
> Key is need to do it RIGHT and prove its right as well
> 
> 
> Right now doing it the really hard and expensive way 
> 
> 
> Sent from my iPhone
> 
> On Jun 1, 2013, at 4:08 PM, Bob Camp <lists at rtty.us> wrote:
> 
>> Hi
>> 
>> Well, back in the day:
>> 
>> Check your gizmo versus LORAN station(s) over time period what ever. Get the report in the mail from USNO a while later. Check your numbers against theirs. Do the math. You have traceability. Yes there's a bit more to it in terms of verifying measurement techniques. 
>> 
>> Today:
>> 
>> Check your gizmo versus GPS sat(s) over time period what ever. Get on the web and get the data from NIST the same day. Check your numbers against theirs. Do the math. You have traceability. Yes there's a bit more to it interns of verifying measurement techniques. 
>> 
>> If you were doing it correctly with LORAN, it's actually faster / easier today. If you were shortcutting the process back in the day, then it's pretty much the same shortcut today. 
>> 
>> If you are hearing that it's a whole lot more expensive today because LORAN is gone, that's not really the full story….
>> 
>> On Jun 1, 2013, at 3:02 PM, Scott McGrath <scmcgrath at gmail.com> wrote:
>> 
>>> True
>>> 
>>> However with LORAN and to a lesser extent WWVB traceability process was well/known and documented and had been in place for decades and was easy to implement correctly     With GPS not so much especially with S/A. Supposedly the new satellites don't have S/A but since the GPS satellites are primarily military in nature how will precise positioning be denied in emergency situations.  Shut down L1?,  dither the signal ????  Or is S/A still there and how does a T/F user respond to GPS not running normally???
>> 
>> Every sat now in orbit has data on the NIST site. The verification process (go to NIST and get the report) is how you see that things are running correctly. Same as the process you should have used with LORAN. The rest assumes that GPS is turned off, that's a completely different issue than any form of traceability. 
>> 
>>> 
>>> A colleague of mine runs a cal lab. Guy is a wizard with physical and electrical standards    
>>> 
>>> I run some of my gear there in exchange for calibration of my instruments as lab has temp / pressure / humidity controls for physical standards so we both benefit.
>>> 
>>> Since the demise of LORAN and WWVB (although d-PSKer may allow us to bring spectracoms and 117a's back.  
>>> 
>>> To achieve traceability we have been shipping our CS and some Rb standards under power to labs who have achieved traceability
>> 
>> Back in the day LORAN boxes cost more in real dollars than GPS boxes cost today. With inflation, GPS is significantly cheaper to set up. LORAN coverage never was as good as GPS is today. It got better as time went on, but it never could give you the performance you can get from GPS now. 
>> 
>>> 
>>> This is is a pain to say the least.  The procedures currently are not well documented on achieving traceability in the age of GPS only.    
>> 
>> The process for legal traceability to LORAN was not all that well documented. The approach with GPS is roughly 90% the same. The difference is you go to here not there for the data you need.
>> 
>>> 
>>> And it's also true that most people confuse traceability with adjustment.  In reality it's more of a chain of data with documented values all the way back to NIST or other national standards lab
>> 
>> ….. I'd much rather get the data from NIST near real time than wait for a report in the mail. 
>> 
>> If you really want to do it the easy way - NIST will set up a nice automated system on your site. The gizmo works *very* well, we had one for a few years. That's not something they would have done back in the days of LORAN. 
>> 
>> 
>> Bob
>> 
>>> 
>>> 
>>> 
>>> 
>>> Sent from my iPhone
>>> 
>>> On Jun 1, 2013, at 1:18 PM, Bob Camp <lists at rtty.us> wrote:
>>> 
>>>> Hi
>>>> 
>>>> 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:
>>>>>> Hi
>>>>>> 
>>>>>> 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.
>>>> 
>>>> Bob
>>>> 
>>>>> Cheers,
>>>>> Magnus
>>>>> 
>>>>>> Bob
>>>>>> 
>>>>>> On May 31, 2013, at 4:37 PM, Charles P. Steinmetz<charles_steinmetz at lavabit.com>  wrote:
>>>>>> 
>>>>>>> Scott wrote:
>>>>>>> 
>>>>>>>> How are those of you dealing with traceability in the commercial space
>>>>>>> 
>>>>>>> The topic is known as "legal metrology."  Start here:
>>>>>>> 
>>>>>>> <http://www.nist.gov/traceability/nist_traceability_policy_external.cfm>
>>>>>>> 
>>>>>>> You need to click through lots of links to get the whole picture.  I believe the material is printed in the NIST Administrative Manual.
>>>>>>> 
>>>>>>> Other potentially helpful links:
>>>>>>> 
>>>>>>> <http://tf.nist.gov/general/pdf/2289.pdf>
>>>>>>> 
>>>>>>> <http://tf.nist.gov/seminars/2002%20NIST%20Seminar%20-%20Traceability%20and%20Legal%20Metrology.ppt>
>>>>>>> 
>>>>>>> <http://www.icllabs.com/pdfs/A2LA_P102%20Policy%20on%20Measurement%20Traceability.pdf>
>>>>>>> 
>>>>>>> <http://tf.nist.gov/general/pdf/1305.pdf>
>>>>>>> 
>>>>>>> 
>>>>>>> Best regards,
>>>>>>> 
>>>>>>> Charles
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
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