RADIO TIME SIGNALS
In the United States, the National Bureau of Standards operates two radio stations providing constant time information that mariners can use for navigational work. The stations are WWV located in Fort Collins, Colorado, and WWVH located in Maui, Hawaii. The stations, in addition to providing continuous time signals, also provide marine storm warnings, geophysical alerts, Omega navigation system status reports, and time corrections when required. There are additional services available, but they are not generally used by the mariner.
Radio station WWV broadcasts on frequencies of 2.5 MHz, 5.0 MHz, 10.0 MHz, 15.0 MHz, and 20.0 MHz. Radio station WWVH broadcasts on frequencies of 2.5 MHz, 5.0 MHz, 10.0 MHz, and 15.0 MHz. The stations can be distinguished from one another because WWV utilizes a male announcer and WWVH utilizes a female announcer. The listener should use signals from the nearest station for time calibration. For additional information on National Bureau of Standards time services and formats, you should consult either Pub. No. 117 A or 117B.
International time signals are also available from many other nations on the shortwave bands. Normally you can pick up the stations operated by the National Bureau of Standards anywhere in the world. There are also stations broadcasting from India, France, Switzerland, Italy, Japan, Argentina, England, Czechoslovakia, the Soviet Union, South Africa, and Canada. Frequencies and periods of operation can be located in any general shortwave listener's guide. In some areas of the western North Atlantic and eastern Pacific, radio station CHU located in Ottawa, Canada, can be picked up more easily than the NBS stations. CHU broadcasts eastern standard time in English and French at 3.33 MHz, 7.335 MHz, and 14.67 MHz continuously.
