Ultrahigh frequency waves (UHF) are a type of short radio wave. Their frequency ranges from 300 to 3,000 megahertz. One megahertz equals 1 million hertz (cycles per second). The wavelength (distance between successive wave crests) of UHF waves measures from 4 to 40 inches (0.1 to 1 meter).
UHF waves are widely used in television broadcasting. UHF waves also are used in aircraft and ship navigation and for police and emergency communication. Cellular telephone networks and household cordless phones also use UHF. Other uses include two-way radio communication (walkie-talkies), satellite radio, and radio astronomy. In some cases, UHF waves provide a communication link between vehicles traveling in space and monitoring stations located on Earth.
UHF waves mainly travel in a straight line, and they cannot pass through Earth. For this reason, the transmission of UHF waves between two points on the earth is limited by the curvature of the earth to 50 miles (80 kilometers) or less. Certain radio waves that have frequencies lower than those of UHF waves can be reflected off the upper layers of the atmosphere to reach beyond Earth’s curvature. As a result, they can be transmitted much farther along Earth’s surface than UHF waves in some cases.
See also Short waves ; Television (Broadcasting) .
