WWVH - Broadcast Format

Broadcast Format

The WWVH signal is extremely similar to the WWV signal, but some changes have been made to reduce confusion if both are heard at once:

• The 5 ms second ticks are 6 cycles of 1200 Hz rather than 5 cycles of 1000 Hz. The 800 ms minute beep is also 1200 Hz. (Like WWV, this is omitted during minutes 29 and 59, and changed to 1500 Hz at the top of each hour.)
• The voice announcements use a female voice (that of Jane Barbe) and last 7.5 seconds starting 15 seconds before the minute. (WWV broadcasts in a male voice during the last 7.5 seconds of each minute.)
• The audio tones sent during the first 45 seconds of most minutes are swapped: 600 Hz is played during even minutes, and 500 Hz is played during odd minutes. (Receiving both simultaneously gives the listener a sound similar to a continuously-ringing chime.)
• The A440 tone marking the hour is sent during minute 1 (as opposed to minute 2 for WWV). Like WWV, it is omitted during the first hour of each UTC day.
• The audio tones are suppressed while WWV is transmitting voice announcements: minutes 00, 08–10, 14–19, and 30.
• The voice announcements are rescheduled relative to WWV:
  • Station identification is made during minutes 29 and 59 (vs. 00 and 30)
  • GPS satellite health reports are transmitted during minutes 43 and 44 (vs. 14 and 15)
  • NOAA space weather geoalerts are transmitted during minute 45 (vs. 18)
  • National Weather Service storm warnings for all sections of the Pacific ocean are broadcast during minutes 48–51, overflowing to minute 52 when necessary (vs. Atlantic and northeast Pacific information during 08–10 and 11).
  • Minutes 03 and 47 are used for NIST special announcements when necessary (vs. 04 and 16).