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...)
The Quatermass Memoirs is a British radiodrama-documentary, originally broadcast in 5 episodes on BBC Radio 3 in March 1996. Written by Nigel Kneale, it was born out of his Quatermass series of films and television serials, which had first been broadcast in the 1950s. The idea for the show appeared as BBC radio intended to create a season of programming looking back at the 1950s, and it was the final piece of writing Kneale completed relating to the character.
The show is centered on the character of Professor Bernard Quatermass who, albeit older than in the previous series, is "the same very concerned scientist" but worried about his previous decisions. Andrew Keir, who had played Quatermass in the 1967 film Quatermass and the Pit, was chosen to voice the character. Later, Nigel Kneale himself became dismissive of the serial, but critics gave the production relatively positive reviews. (Full article...)
The following are images from various radio-related articles on Wikipedia.
Image 1In 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 5Diagram 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 8Frequency 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. (from Radio)
Image 10Donald Manson working as an employee of the Marconi Company (England, 1906) (from History of radio)
Image 11Comparison of AM and FM modulated radio waves (from Radio)
Image 12Around 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 13British Post Office engineers inspect Guglielmo Marconi's wireless telegraphy (radio) equipment in 1897. (from History of radio)
Image 14An early iPhone with its GPS navigation app in use. (from Radio)
Image 21Animated 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 results in oscillation of the electrons in the rods, 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 24Oliver Lodge's 1894 lectures on Hertz demonstrated how to transmit and detect radio waves. (from History of radio)
Image 25Heinrich Rudolf Hertz (1856–1894) proved the existence of electromagnetic radiation. (from History of radio)
Image 26Reginald Fessenden (around 1906) (from History of radio)
Image 27Radio 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)
Image 28Neighborhood wireless WAN router on telephone pole (from Radio)
Image 29Advertisement placed on November 5, 1919 in the Nieuwe Rotterdamsche Courant, announcing PCGG's debut broadcast scheduled for the next evening. (from Radio broadcasting)
Image 30Animation 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)
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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