Portal:Radio

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The Radio Portal

Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver. In addition to communication, radio is used for 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 to a receiver that is typically colocated with the transmitter. In radio navigation systems such as GPS and VOR, a mobile navigation instrument receives radio signals from multiple 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. (Full article...)

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Orson Welles explaining to reporters that he had not intended to cause panic (October 31, 1938)

"The War of the Worlds" was a Halloween episode of the radio series The Mercury Theatre on the Air directed and narrated by Orson Welles as an adaptation of H. G. Wells's novel The War of the Worlds (1898) that was performed and broadcast live at 8 pm ET on October 30, 1938, over the CBS Radio Network. The episode is famous for inciting a panic by convincing some members of the listening audience that a Martian invasion was taking place, though the scale of panic is disputed, as the program had relatively few listeners.

The episode begins with an introductory monologue based closely on the opening of the source novel, after which the program takes on the format of an evening of typical radio programming being periodically interrupted by news bulletins. The first few bulletins interrupt a program of live music and are relatively calm reports of unusual explosions on Mars followed by a seemingly unrelated report of an unknown object falling on a farm in Grovers Mill, New Jersey. The crisis escalates dramatically when an on-scene reporter at Grovers Mill describes creatures emerging from what is evidently an alien spacecraft. The aliens employ a heat ray against police and onlookers, and the radio correspondent describes the attack in increasing panic until his audio feed abruptly goes dead. This is followed by a rapid series of news updates detailing the beginning of a devastating alien invasion and the US military's futile efforts to stop it. The first portion of the episode climaxes with a live report from a rooftop in Manhattan, from where a correspondent describes citizens fleeing from poison smoke released by towering Martian "war machines" until he coughs and falls silent. Only then does the program take its first break, about thirty minutes after Welles's introduction. (Full article...)

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The following are images from various radio-related articles on Wikipedia.

Image 1Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
Image 2Advertisement placed on November 5, 1919, Nieuwe Rotterdamsche Courant announcing PCGG's debut broadcast scheduled for the next evening (from Radio broadcasting)
Image 3Animated diagram of a half-wave dipole antenna receiving a radio wave. The antenna consists of two metal rods connected to a receiver $R$ . The electric field ( $E$ , green arrows) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive (+) and negative (−). Since the length of the antenna is one half the wavelength of the wave, the oscillating field induces standing waves of voltage ( $V$ , represented by red band) and current in the rods. The oscillating currents (black arrows) flow down the transmission line and through the receiver (represented by the resistance $R$ ). (from Radio wave)
Image 4Wildlife officer tracking radio-tagged mountain lion (from Radio)
Image 5Worldwide presence of Radio Maria broadcasters (from Radio broadcasting)
Image 6Frequency spectrum of a typical modulated AM or FM radio signal. It consists of a component C at the carrier wave frequency $f_{c}$ with the information (modulation) contained in two narrow bands of frequencies called sidebands (SB) just above and below the carrier frequency. (from Radio)
Image 7The first commercial AM Audion vacuum tube radio transmitter, built in 1914 by Lee De Forest who invented the Audion (triode) in 1906 (from History of radio)
Image 8Reginald Fessenden (around 1906) (from History of radio)
Image 9British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Image 10An antenna farm hosting various radio antennas on Sandia Peak near Albuquerque, New Mexico, US (from Radio)
Image 11Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves. (from History of radio)
$Image 12Early experiment demonstrating refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio)$

Image 12Early experiment demonstrating refraction of microwaves by a paraffin lens by John Ambrose Fleming in 1897 (from History of radio)
Image 13Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio)
Image 14Neighborhood wireless WAN router on telephone pole (from Radio)
Image 15Volkswagen's RNS-510 receiver supports Sirius Satellite Radio. (from Radio)
Image 16In the 1920s, the United States government publication, "Construction and Operation of a Simple Homemade Radio Receiving Outfit", showed how almost any person handy with simple tools could a build an effective crystal radio receiver. (from History of radio)
Image 17A laptop (with Wi-Fi module) and a typical home wireless router (on the right) connecting it to the Internet. The laptop shows its own photo (from Radio)
Image 18Around 1920, radio broadcasting started to get popular. The Brox Sisters, a popular singing group, gathered around the radio at the time. (from History of radio)
Image 19Use of a sound broadcasting station (from Radio broadcasting)
Image 20Diagram of the electric fields (E) and magnetic fields (H) of radio waves emitted by a monopole radio transmitting antenna (small dark vertical line in the center). The E and H fields are perpendicular, as implied by the phase diagram in the lower right. (from Radio wave)
Image 21Comparison of AM and FM modulated radio waves (from Radio)
Image 22The Regency TR-1, which used Texas Instruments' NPN transistors, was the world's first commercially produced transistor radio in 1954. (from History of radio)
Image 23Animation of a half-wave dipole antenna radiating radio waves, showing the electric field lines. The antenna in the center is two vertical metal rods connected to a radio transmitter (not shown). The transmitter applies an alternating electric current to the rods, which charges them alternately positive (+) and negative (−). Loops of electric field leave the antenna and travel away at the speed of light; these are the radio waves. In this animation the action is shown slowed down tremendously. (from Radio wave)
Image 24Rotating marine radar antenna on a ship (from Radio)
Image 25Control room and radio studio of the Finnish broadcasting company Yleisradio (YLE) in the 1930s. (from Radio broadcasting)
Image 26An early iPhone with its GPS navigation app in use. (from Radio)
Image 27Motorola SCR-536 from WW2, the first walkie-talkie (from Radio)
Image 28Radio 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. (from Radio)

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Did you know...

... that French broadcast regulators failed to mediate a dispute between four Jewish radio stations in Paris sharing the same frequency: Judaïques FM, RCJ, Radio J, and Radio Shalom?
... that Chicago Radio public address systems were used extensively by the pro-independence Indian National Congress during the British Raj?
... that pioneer radiologist Sydney Domville Rowland coined the term "skiagraphy"?
... that the Indian independence movement's underground Congress Radio once submerged their equipment in the Godavari River?
... that the first song played on That's 60s was the same song Tony Blackburn had played on BBC Radio 1 more than 55 years earlier?
... that Shanthi Kalathil believes Radio Free Asia "filled a critical role in combating Chinese disinformation"?

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“

People who think radio acting is easy are wrong, because you got nothing to work with but your voice.

”

— Melanie Griffith

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Radio topics

Formats	Community radio, Music radio, Old-time radio, Radio comedy, Radio documentary, Radio drama, Sports radio, Talk Radio, Top 40
Networks	BBC Radio, Blue Network, Columbia Broadcasting System, Mutual Broadcasting System, National Broadcasting Company, Sirius Satellite Radio, XM Satellite Radio
People	Fred Allen, Gracie Allen, Don Ameche, Jack Benny, Edgar Bergen, Jagadish Chandra Bose, George Burns, Charlamagne tha God, Ronald Colman, Jim Connors, Frank Conrad, Norman Corwin, Charles Coughlin, Frankie Crocker, Ebro Darden, Alice Faye, Stan Freberg, Sean Hannity, Vaughn Harper, Phil Harris, Bob Hope, Hal Jackson, Spike Jones, Tom Joyner, Hans von Kaltenborn, Larry Elder, Larry King, Kay Kyser, Frances Langford, Rush Limbaugh, Guglielmo Marconi, Angie Martinez, Elizabeth McLeod, J. Carrol Naish, Ozzie Nelson, Arch Oboler, Dorothy Parker, Virginia Payne, Harold Peary, David Sarnoff, Red Skelton, Kate Smith, Stephen A. Smith, Howard Stern, Nikola Tesla, Jonathan Toubin, Lurene Tuttle, Rudy Vallée, Fred Waring, Orson Welles, Wendy Williams, Angela Yee
Shows	Abbott and Costello, Amos 'n' Andy, Arch Oboler's Plays, The Breakfast Club, Burns and Allen, Cavalcade of America, CBS Radio Mystery Theater, Dragnet, Duffy's Tavern, Ebro in the Morning, 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, Tom Joyner Morning Show, Rush Limbaugh Show
Technology	Amateur radio, AM broadcasting, FM broadcasting, International broadcasting, Internet Radio, Digital Radio Mondiale, HD Radio, Digital Audio Broadcasting, GNU Radio, Software-defined radio, Transistor radio, Vacuum tube, Pirate radio Top 40
Industry	Radio promotion

WikiProjects

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)
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)
Amateur Radio (Inactive), 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)