[time-nuts] WWVB Response

David McGaw n1hac at Alum.Dartmouth.ORG
Wed Sep 26 20:34:03 UTC 2012


Hi John,

Thank you very much for the clarification.

Best regards,

David McGaw N1HAC
Dartmouth College
Dept. of Physics and Astronomy


On 9/26/12 2:29 PM, John Lowe wrote:
> Dear Time-Nuts Forum,
>
> In an attempt to quiet the discussion that has started, I will take 
> the unusual step and address this forum.
>
> NIST is providing full disclosure of the WWVB PM format.  There are no 
> hidden bits or protocols.  We will continue to be entirely forthcoming 
> with the WWVB broadcast both in its content and its schedule.  All 
> information is available and will continue to be available at:
>
> http://www.nist.gov/pml/div688/grp40/wwvb.cfm
>
> NIST has never been in the business of developing, designing or 
> producing receiver designs.  We provide the format and allow our users 
> to create designs as they see fit.  Individuals are invited to design 
> receivers based on the format provided.
>
> We have taken great care to preserve the existing AM format of the 
> WWVB transmission.  We expect the vast majority of AM envelope-type 
> receivers will continue to operate as designed and will detect the 
> Time-of-Day.  Unfortunately, there are devices out there that detected 
> the phase of the carrier through a Phase-Locked-Loop. These devices 
> will no longer function as designed.  There are methods of creating an 
> interface to recover the signal for these devices, some of which have 
> been discussed and presented in this forum.  It is an unfortunate 
> consequence of improving the reception capability of our broadcast 
> that this segment of our loyal user base are so adversely affected.  
> The decision to proceed was not taken lightly, but in the end it was 
> decided that the improvement in reception capability (especially along 
> the JJY interference prone East Coast) outweighed the loss of use of 
> existing PLL devices.
>
> It should be noted that the carrier-phase information is still there 
> and will provide the same level of reference calibration capability as 
> it always has, it just must be extracted in a new way.  Maybe this 
> change will prompt a commercial enterprise to develop a new WWVB 
> frequency reference device as there has been no commercially produced 
> frequency reference devices manufactured or supported in some time.
>
> I have given much effort in being available to answer questions and 
> provide information concerning this transition and I will continue to 
> be available to help.  I hope this response to this forum aids in that 
> effort.
>
> Regards,
>
> John Lowe
> WWVB Broadcast Manager
> NIST Time and Frequency Division
>
>
>
>
>
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