[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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