WWVH is the callsign of the U.S.

National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical s ...

shortwave Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 me ...

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a tr ...

time signal A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, a ...

station located at the Barking Sands Missile Range, in

Kekaha Kekaha (literally, "the place" in Hawaiian) is a census-designated place (CDP) in Kauai County, Hawaii, United States. The population was 3,715 at the 2020 census, up from 3,175 at the 2000 census. History For most of the 20th century, the K ...

, on the island of

Kauai Kauai, () anglicized as Kauai ( ), is geologically the second-oldest of the main Hawaiian Islands (after Niʻihau). With an area of 562.3 square miles (1,456.4 km2), it is the fourth-largest of these islands and the 21st largest islan ...

in the state of

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

. WWVH is the Pacific sister station to WWV, and has a similar broadcast format. Like WWV, WWVH's main function is the dissemination of official U.S. Government time, through exactly the same methods as found on WWV's signal. To minimize interference with the WWV broadcasts on the same frequencies, WWVH's broadcasts on 5, 10 and 15 MHz are directional, pointed primarily west. Despite this strategy, in certain places, particularly on the west coast of North America; and at certain times, due to

ionospheric The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an ...

conditions, the listener can actually hear 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 Jane Barbe ( ; July 29, 1928 – July 18, 2003) was an American voice actress and singer. She was known as the "Time Lady" for the recordings she made for the Bell System and other phone companies. The ubiquity of her recordings eventually made he ...

) to distinguish itself from WWV, which uses a male voice. WWVH time signals can also be accessed by telephone.

Transmission system

WWVH broadcasts its signal on four transmitters, one for each frequency. The 2.5 MHz transmitter puts out an ERP of 5 kW, while the other transmitters use 10 kW of ERP. The 2.5 MHz antenna is one half-

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tr ...

tall, and radiates in an omnidirectional pattern. The remaining antennas each consist of two elements one half-wavelength tall and horizontally separated by one quarter-wavelength. The signal radiating from one element is in quadrature phase with respect to the signal from the other. This results in a

cardioid In geometry, a cardioid () is a plane curve traced by a point on the perimeter of a circle that is rolling around a fixed circle of the same radius. It can also be defined as an epicycloid having a single cusp. It is also a type of sinusoidal ...

radiation pattern with a maximum gain directed west.

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 1,200 Hz rather than 5 cycles of 1,000 Hz. The 800 ms minute beep is also 1,200 Hz. (Like WWV, this is omitted during minutes 29 and 59, and changed to 1,500 Hz at the top of each hour.) * The voice announcements use a female voice (that of

) 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 The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...

space weather geoalerts are transmitted during minute 45 (vs. 18) **

National Weather Service The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...

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). Like WWV, prior to the

OMEGA Omega (; capital: Ω, lowercase: ω; Ancient Greek ὦ, later ὦ μέγα, Modern Greek ωμέγα) is the twenty-fourth and final letter in the Greek alphabet. In the Greek numeric system/ isopsephy ( gematria), it has a value of 800. The ...

Navigation System shutdown in 1997, the OMEGA status report was broadcast at :47 past the hour.

Half-hourly station identification announcement

WWVH identifies itself twice each hour, at 29 and 59 minutes past the hour. The text of the identification is as follows: Reception reports sent to that address will on request be answered with a

QSL card A QSL card is a written confirmation of either a two-way radiocommunication between two amateur radio or citizens band stations; a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station; or the re ...

Telephone service

WWVH's time signal can also be accessed by calling +1 (808) 335-4363.

References

External links