[time-nuts] WWVB Response

[John Lowe]

Thank you.
On 9/26/2012 2:34 PM, David McGaw wrote:
> 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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