Short waves is a term for radio waves with wavelengths shorter than those used in amplitude modulation (AM) radio transmissions. The wavelengths, however, are longer than those of waves used in very high frequency (VHF) television transmissions. Wavelength is the distance between successive repeated patterns of a wave. Short waves have wavelengths from about 10 to 100 meters (33 to 330 feet). Short wave transmissions reflect off Earth’s ionosphere, part of the upper atmosphere, enabling long-distance radio communication without the use of satellites.
Wavelength is related to frequency. As frequency increases, wavelength decreases. Short waves have frequencies from about 3 to 30 megahertz. One megahertz (MHz) equals 1 million hertz (cycles per second).
Short waves carry conversations between amateur radio operators, citizens’ band (CB) radio operators, and emergency service personnel. International communications services, such as the British Broadcasting Corporation (BBC) World Service, make long-distance broadcasts via short waves.
See also Ionosphere ; Radio (Transmitting radio waves) ; Radio, Amateur .
