WWVH is the callsign of the U.S. National Institute of Standards and Technology's shortwave radio time signal station located at the Pacific Missile Range Facility Barking Sands, in Kekaha, on the island of Kauai in the state of Hawaii. 21°59′16″N 159°45′47″W / 21.98778°N 159.76306°W
WWVH is the Pacific sister station to WWV, and has a similar broadcast format. Like WWV, WWVH's main function is the dissemination of the official U.S. Government time and frequency standard.
Due to ionospheric conditions, at certain times and locations some listeners may receive both WWV and WWVH on the same frequency at the same time. The information modulated on the carrier is modified to reduce confusion if both are received simultaneously. In particular, voice announcements on one correspond to silent periods on the other. WWVH uses a female voice (Jane Barbe) to distinguish itself from WWV, which uses a male voice.
WWVH time signals can also be accessed by telephone at +1 (808) 335-4363.
Station | Year in service |
Year out of service |
Radio frequencies |
Audio frequencies |
Musical pitch |
Time intervals |
Time signals |
UT2 correction |
Propagation forecasts |
Geophysical alerts |
---|---|---|---|---|---|---|---|---|---|---|
WWV | 1923 | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | |
WWVH | 1948 | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ||
WWVB | 1963 | ✔ | ✔ | ✔ | ✔ | |||||
WWVL | 1963 | 1972 | ✔ |
WWVH antenna coordinates[2] | |
---|---|
2.5 MHz | 21°59′20.9″N 159°45′52.4″W / 21.989139°N 159.764556°W |
5 MHz | 21°59′10.8″N 159°45′44.8″W / 21.986333°N 159.762444°W |
10 MHz | 21°59′18.2″N 159°45′51.3″W / 21.988389°N 159.764250°W |
15 MHz | 21°59′15.3″N 159°45′50.0″W / 21.987583°N 159.763889°W |
WWVH broadcasts its signal on four transmitters, one for each frequency. The 2.5 MHz transmitter puts out 5 kW, while the other transmitters provide 10 kW. The 2.5 antennas are one quarter-wavelength tall, and radiate in an omnidirectional pattern. The 10.0 and 15.0 MHz antennas are omnidirectional half-wave antennas. The 5 MHz antenna consists of two elements one half-wavelength tall and horizontally separated by one quarter-wavelength. This directional antenna produces a broad cardioid radiation pattern with a maximum gain directed west.
Emergency stand-by transmitters and antennas are provided for each frequency.
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:[2]
WWVH identifies itself twice each hour, at 29 and 59 minutes past the hour. The text of the identification is as follows:
National Institute of Standards and Technology Time. This is radio station WWVH, Kauai, Hawaii, broadcasting on internationally allocated standard carrier frequencies of 2.5, 5, 10 and 15 megahertz, providing time of day, standard time interval, and other related information. Inquiries regarding these transmissions may be directed to the National Institute of Standards and Technology, Radio Station WWVH, Post Office Box 417, Kekaha, Hawaii 96752. Aloha.
Reception reports sent to that address will on request be answered with a QSL card.[3]
WWVH's time signal can also be accessed by calling +1 (808) 335-4363.[4]