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Enhanced WWVB Broadcast Format Change

Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST Radio Station WWVB has been broadcasting a phase modulation (PM) time code protocol that has been added to the legacy AM/pulse-width-modulation signal. This enhancement to the broadcast, which has been tested throughout 2012, provides significantly improved performance in new products that are designed to receive it. Existing radio-controlled clocks and watches are not affected by this enhancement, and continue to work as before. A detailed technical description of the new format can be found here.

Disciplined oscillator products that track and lock to the 60 kHz WWVB carrier and were designed to work as frequency standards, will not work with the PM signal and will now become obsolete. A few radio controlled clocks that used information from the carrier – specifically the Spectracom NetClock and receivers manufactured by True Time during the 1970s and 1980s – will no longer be able to read the time code and will also be obsolete. For more information, contact Broadcast Manager John Lowe at john.lowe@nist.gov or 303-497-5453.



Broadcast Outages for WWVB

 WWVB Home 2003 Outages 2004 Outages 2005 Outages 2006 Outages 2007 Outages 2008 Outages 2009 Outages

2010 Outages
2011 Outages 2012 Outages 2013 Outages 2014 Outages 2015 Outages 2016 Outages 2017 Outages

During normal operation, the 60 kHz signal from WWVB is transmitted 24 hours per day, 7 days a week. The table includes periods when the signal was off or intermittent for more than 5 minutes.

Date MJD Began (UTC) Ended (UTC)

14 October 2014

56944

0708

0824

13 October 2014

56943

0238

0328

3 October 2014

56933

0029

0119

20 September 2014

56920

0549

0639

13 September 2014

56913

2117

2206

22 August 2014

56891

0057

0125

21 August 2014

56890

1010

1119

27 July 2014

56865

 

0021

26 July 2014

56864

2236

 

25 July 2014

56863

0653

0811

8 July 2014

56846

0158

0248

3 July 2014

56841

0023

0140

4 June 2014

56812

1147

1233

12 May 2014

56789

2234

2252

11 May 2014

56788

1450

1603

10 May 2014

56787

0442

0530

31 March 2014

56747

0922

1042

15 March 2014

56731

1443

1547

11 February 2014

56699

2327

2337

09 February 2014

56697

1906

2006

06 February 2014

56694

0638

0745

12 January 2014

56669

1918

1956

12 January 2014

56669

1115

1223

10 January 2014

56667

0818

0918

09 January 2014

56666

1037

1152

04 January 2014

56661

0707

0801