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 accepts 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. (Full article...)
It has 32 overseas correspondent bureaux and 6 main regional bureaux, and broadcasts over 2,700 hours of programming each day (24 hours in English), including news, current affairs, and features on politics, the economy, culture, science and technology. Its overseas reporting involves 65 languages. More than 50 shortwave transmitters are used to cover most of the world; it is broadcast via the internet and numerous satellites; and its programs are rebroadcast by many local AM and FM radio stations worldwide. (Full article...)
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 in the 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 4Around 1920, radio broadcasting started to get popular. A group of women gathered around the radio at the time. (from History of radio)
Image 5British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Image 8Diagram 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 9Heinrich Rudolf Hertz (1856-1894) discovered an important step in the process of radio development called the Hertzian waves. (from History of radio)
Image 10Animation of a half-wave dipoleantenna 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 enormously. (from Radio wave)
Image 17In 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)
... that conductor and politician Klaus Bernbacher was responsible for 600 Radio Bremen music broadcasts, including of the original version of Schönberg's Gurre-Lieder?
... that Travancore Radio's first English-language broadcaster, Indira Joseph Venniyoor, was paid 69 rupees (then equivalent to US$14.50) for her broadcasts in 1949?
... that Irish folklorist Bríd Mahon wrote the first of her hundreds of radio scripts for Radio Éireann as a child, discussing the history and music of County Cork?
RadioDecember 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)
PodcastingJanuary 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)
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