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Shortwave radio refers to the HF (high frequency) portion of the radio spectrum, between 3,000–30,000 kHz.[1] Shortwave radio received its name because the wavelengths in this band are shorter than those used for medium and low frequency bands first used for radio communications.

Initially thought to be useless, shortwave radio now has many applications where the behaviour of radio waves in the Earth's atmosphere make long-range communication possible. Shortwave radio is used for broadcasting of voice and music, and long-distance communication to ships and aircraft, or to remote areas out of reach of wired communication or other radio services. Amateur radio on these frequencies can provide hobby, educational and emergency communication.



The discovery of long-distance shortwave propagation

Amateur radio operators are credited with the discovery of long-distance communication on the shortwave bands. Early long-distance services used surface wave propagation at very low frequencies[2], which are attenuated along the path. Longer distances and higher frequencies using this method meant more signal attenuation. This, and the difficulties of generating and detecting higher frequencies, made discovery of shortwave propagation difficult for commercial services.

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