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...)
John Florence Sullivan (May 31, 1894 – March 17, 1956), known professionally as Fred Allen, was an American comedian. His absurdist topically-pointed radio program The Fred Allen Show (1932–1949) made him one of the most popular and forward-looking humorists in the
Golden Age of American radio.
His best-remembered gag was his long-running mock feud with friend and fellow comedian
Jack Benny, but that was only part of his appeal. Radio historian
John Dunning (in On the Air: The Encyclopedia of Old-Time Radio) wrote that Allen was perhaps radio's most admired comedian and most frequently censored. A master
ad libber, Allen often tangled with his network's executives and often barbed them on the air over the battles while developing routines whose style and substance influenced fellow comic talents, including
Groucho Marx,
Stan Freberg,
Henry Morgan, and
Johnny Carson; his avowed fans also included President
Franklin D. Roosevelt, humorist
James Thurber, and novelists
William Faulkner,
John Steinbeck, and
Herman Wouk, who began his career writing for Allen. (Full article...)
Image 3Animation 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 tremendously. (from Radio wave)
Image 4Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation (from History of radio)
Image 8Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
Image 9Animated 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 10Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves (from History of radio)
Image 11Advertisement placed on November 5, 1919, Nieuwe Rotterdamsche Courant announcing PCGG's debut broadcast scheduled for the next evening (from Radio broadcasting)
Image 13In 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 14British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Image 15Around 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 17Diagram 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)
... that the relative rarity of the
radiodontTitanokorys(video featured) in
Marble Canyon suggests that the deposits in which it was found may represent the outermost edge of its distribution in life?
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)
Radio StationsFebruary 15, 2005 "...to coordinate the activities of creating and maintaining articles about radio stations." (Example: Pulse FM Kingborough & Huon)
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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