The LF is partially utilized for the sound broadcasting in Europe, Africa, and some other regions, while in Japan, it is used for Loran C stations for radio navigation, navigation beacons for vessels and aircrafts, and standard frequency and time signal stations providing information on the standard frequency and time signal. The LF had been in use for radiotelegraphy till around 1930 however, it has not gradually been in use for the purpose as it required a large-scale antenna and transmitting device and the high frequency communication has been largely developed. The LF radio wave has a wavelength between 1km and 10km, and it propagates very far. The VLF radio wave has a very long wavelength between 10km and 100km, and it propagates on the ground surface, past small mountains.
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