Shortwave radio is radio communication using the upper MF (medium frequency) and all of the HF (high frequency) portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m (1500 kHz) which marked the original upper limit of the medium frequency band first used for radio communications. The broadcast medium wave band now extends above the 200 m/1500 kHz limit, and the amateur radio 1.8 MHz – 2.0 MHz band (known as the "top band") is the lowest-frequency band considered to be 'shortwave'.
Initially thought to be useless, shortwave radio now has many applications where the behaviour of radio waves in the Earth's atmosphere makes 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. Additionally, amateur radio on these frequencies can provide hobby, educational and emergency two-way communication.
Read more about Shortwave Radio: Propagation Characteristics, Types of Modulation, Uses, Shortwave Broadcasting, Shortwave Listening, Amateur Radio, Utility Stations, Unusual Signals, Shortwave Broadcasts and Music, Shortwave's Future
Famous quotes containing the word radio:
“The radio ... goes on early in the morning and is listened to at all hours of the day, until nine, ten and often eleven o’clock in the evening. This is certainly a sign that the grown-ups have infinite patience, but it also means that the power of absorption of their brains is pretty limited, with exceptions, of course—I don’t want to hurt anyone’s feelings. One or two news bulletins would be ample per day! But the old geese, well—I’ve said my piece!”
—Anne Frank (1929–1945)