A variety of radio antennas
on Sandia peak
, New Mexico, US. Transmitting antennas are often located on mountain peaks, to give maximum transmission range.
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by a radio receiver connected to another antenna. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking and satellite communication among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft and missiles, a beam of radio waves emitted by a radar transmitter reflects off the target object, and the reflected waves reveal the object's location. In radio navigation systems such as GPS and VOR, a mobile receiver receives radio signals from navigational radio beacons whose position is known, and by precisely measuring the arrival time of the radio waves the receiver can calculate its position on Earth. In wireless radio remote control devices like drones, garage door openers, and keyless entry systems, radio signals transmitted from a controller device control the actions of a remote device.
Applications of radio waves which do not involve transmitting the waves significant distances, such as RF heating used in industrial processes and microwave ovens, and medical uses such as diathermy and MRI machines, are not usually called radio. The noun radio is also used to mean a broadcast radio receiver.
The Hitchhiker's Guide to the Galaxy is a science fiction comedy radio series written by Douglas Adams (with some material in the first series provided by John Lloyd). It was originally broadcast in the United Kingdom by the BBC, and was soon afterwards broadcast on global short wave radio on the BBC World Service, in 1978. Broadcasting by National Public Radio (one of their first to occur in stereo) in the United States followed in March, 1981, with a repeat broadcast in September. The following year, 1982, the BBC series was carried by CBC Radio (Canadian Broadcasting Corporation).
A pilot programme was commissioned in March 1977, and was recorded by the end of the following June. A second series was commissioned in 1979, and this was transmitted in 1980. Episodes of the first series were specially re-recorded for release on LP records and cassettes. After the 1980 transmissions of the second radio series, the first series was adapted for television; it included some material originally written by Adams for stage adaptations and the aforementioned LP adaptation. This in turn was followed by five novels, a computer game, and adaptations into three series of comic books.
Adams considered writing a third radio series, to be based on his novel Life, the Universe and Everything, in 1993 but the project did not begin for another ten years, after Adams's death. Dirk Maggs, with whom Adams had discussed the new series in 1993, 1997 and 2000, eventually directed and co-produced radio series adaptations of that novel, as well as So Long, and Thanks for All the Fish and Mostly Harmless. These became the third, fourth and fifth radio series. The third series was recorded in 2003 and transmitted in September and October 2004, and the fourth and fifth series were recorded in late 2004 and early 2005 and transmitted in May and June 2005. Recordings of all five series have been released on audio cassette and compact disc, and the third series was released on DVD in 2006, after being "delayed" more than once.
Frequency spectrum of a typical modulated AM or FM radio signal. It consists of a component C at the carrier wave frequency with the information (modulation) contained in two narrow bands of frequencies called sidebands (SB) just above and below the carrier frequency.
A variety of radio antennas on Sandia peak near Albuquerque, New Mexico, US. Transmitting antennas are often located on mountain peaks, to give maximum transmission range.
Laptop computer and typical home wireless router (right) connecting it to the Internet
Radio communication. Information such as sound is converted by a transducer such as a microphone to an electrical signal, which modulates a radio wave produced by the transmitter. A receiver intercepts the radio wave and extracts the information-bearing modulation signal, which is converted back to a human usable form with another transducer such as a loudspeaker.
Comparison of AM and FM modulated radio waves
Rotating marine radar antenna on ship.
Neighborhood wireless WAN router on telephone pole
Wildlife officer tracking radio tagged mountain lion
||With electricity we were wired into a new world, for electricity brought the radio, a "crystal set" and with enough ingenuity, one could tickle the crystal with a cat's whisker and pick up anything.
Howard Stern (born Howard Allen Stern on January 12, 1954) is an American radio and TV personality, media mogul, humorist, actor, and author. He is best known for his national radio show, which for many years was syndicated on FM radio stations (and a few AM stations) throughout the United States until his last terrestrial radio broadcast on December 16, 2005. He began broadcasting on the subscription-based Sirius satellite radio service on January 9, 2006.
The self-proclaimed "King of All Media" (a humorous reference to Michael Jackson's appellation "The King of Pop") has been dubbed a shock jock for his highly controversial use of scatological, sexual and racial humor. Stern has said that the show was never about shocking people, but primarily intended to offer his honest opinions on a gamut of issues (ranging from world affairs to problems among his own staff). Though controversial, he is one of the highest-paid radio personalities in the United States and the most fined personality in radio broadcast history.
- Radio December 12, 2006 "...to create, expand, and maintain wikipedia articles related to radio, including radio propagation and reception, radio programming, radio personalities, and the business of radio." (Example: Mutual Broadcasting System)
- Amateur Radio August 24, 2006 "...to improve Wikipedia's articles related to Amateur radio, maintain the amateur radio category and its sub-categories for clean organization, and to produce and maintain templates for Amateur radio-related topic identification." (Example: Amateur radio)
- Radio Stations February 15, 2005 "...to coordinate the activities of creating and maintaining articles about radio stations." (Example: Pulse FM Kingborough & Huon)
- Podcasting January 21, 2007 "...to make Wikipedia's knowledge of notable Podcast and podcast-related information as complete as possible." (Example: Podcast)
||Music radio, Old-time radio, Radio comedy, Radio documentary, Radio drama, Top 40
||BBC Radio, Blue Network, Columbia Broadcasting System, Mutual Broadcasting System, National Broadcasting Company, Sirius Satellite Radio, XM Satellite Radio
||Fred Allen, Gracie Allen, Don Ameche, Jack Benny, Edgar Bergen, Jagadish Chandra Bose, George Burns, Ronald Colman, Jim Connors, Frank Conrad, Norman Corwin, Frankie Crocker, Alice Faye, Stan Freberg, Vaughn Harper, Phil Harris, Bob Hope, Hal Jackson, Spike Jones, Hans von Kaltenborn, Kay Kyser, Frances Langford, Guglielmo Marconi, Elizabeth McLeod, J. Carrol Naish, Ozzie Nelson, Arch Oboler, Dorothy Parker, Virginia Payne, Harold Peary, David Sarnoff, Red Skelton, Kate Smith, Howard Stern, Nikola Tesla, Jonathan Toubin, Lurene Tuttle, Rudy Vallée, Fred Waring, Orson Welles
||Abbott and Costello, Amos 'n' Andy, Arch Oboler's Plays, Burns and Allen, Cavalcade of America, CBS Radio Mystery Theater, Dragnet, Duffy's Tavern, Fibber McGee and Molly, The Goldbergs, The Howard Stern Show, Inner Sanctum Mysteries, The Jack Benny Program, Life with Luigi, Lights Out, Lux Radio Theater, Opie and Anthony, The Archers, The Hitchhiker's Guide to the Galaxy, The Phil Harris-Alice Faye Show, Quiz Kids, The Screen Guild Theater, The Shadow, Suspense, Theater Guild on the Air, Twenty Questions, The Whistler, Yours Truly, Johnny Dollar
||Amateur radio, AM broadcasting, FM broadcasting, International broadcasting, Internet Radio, Digital Radio Mondiale, HD Radio, Digital Audio Broadcasting and GNU Radio, Software-defined radio, Transistor radio, Vacuum tube