Radio control

Radio control (often abbreviated to R/C or simply RC) is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small handheld radio transmitter unlocks or opens doors. Radio control is also used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well. A rapidly growing application is control of unmanned aerial vehicles (UAVs or drones) for both civilian and military uses, although these have more sophisticated control systems than traditional applications. Radio control (often abbreviated to R/C or simply RC) is the use of control signals transmitted by radio to remotely control a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small handheld radio transmitter unlocks or opens doors. Radio control is also used for control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make use of radio-controlled vehicles as well. A rapidly growing application is control of unmanned aerial vehicles (UAVs or drones) for both civilian and military uses, although these have more sophisticated control systems than traditional applications. In 1894, the first example of wirelessly controlling at a distance was during a demonstration by the British physicist Oliver Lodge, in which he made use of a Édouard Branly's coherer to make a mirror galvanometer move a beam of light when an electromagnetic wave was artificially generated. This was further refined by Guglielmo Marconi and William Preece, at a demonstration that took place on December 12, 1896, at Toynbee Hall in London, in which they made a bell ring by pushing a button in a box that was not connected by any wires. In 1897 a British engineer Ernest Wilson had invented a torpedo that was controlled by 'Hertzian' waves. In 1898, at an exhibition at Madison Square Garden, Nikola Tesla demonstrated a small unmanned boat that used a coherer based radio control. In a bit of showmanship, Tesla entertained the audience to make it seem that the boat could apparently obey commands from the audience but it was, in fact, controlled by Tesla interpreting the verbal requests and sending appropriate frequencies to tuned circuits in the boat. Tesla was granted a US patent on this invention on July 1, 1898. In 1903, the Spanish engineer Leonardo Torres y Quevedo presented the 'Telekino' at the Paris Academy of Science, and was granted a patent in France, Spain, Great Britain and the United States. In 1904, Bat, a Windermere steam launch, was controlled using experimental radio control by its inventor, . In 1909 the French inventor Gabet demonstrated what he called his 'Torpille Radio-Automatique', a radio-controlled torpedo. In 1917, Archibald Low as head of the RFC Experimental Works, was the first person to use radio control successfully on an aircraft. During World War I American inventor John Hays Hammond, Jr. developed many techniques used in subsequent radio control including developing remote controlled torpedoes, ships, anti-jamming system's and even a system allowing his remote-controlled ship targeting an enemy ship's searchlights. In 1922 he installed radio control gear on the obsolete US Navy battleship USS Iowa so it could be used as a target ship (sunk in gunnery exercise in March 1923). The Soviet Red Army used remotely controlled teletanks during the 1930s in the Winter War against Finland and fielded at least two teletank battalions at the beginning of the Great Patriotic War. A teletank is controlled by radio from a control tank at a distance of 500–1,500 m, the two constituting a telemechanical group. There were also remotely controlled cutters and experimental remotely controlled planes in the Red Army. In the 1930s, the United Kingdom developed the radio-controlled Queen Bee, a remotely controlled unmanned Tiger Moth aircraft for a fleet's gunnery firing practice. The Queen Bee was superseded by the similarly named Queen Wasp, a purpose-built, target aircraft of higher performance. Radio control was further developed during World War II, primarily by the Germans who used it in a number of missile projects. Their main effort was the development of radio-controlled missiles and glide bombs for use against shipping, a target otherwise both difficult and dangerous to attack. However, by the end of the war, the Luftwaffe was having similar problems attacking Allied bombers and developed a number of radio command guided anti-aircraft missiles, none of which saw service. The effectiveness of the Luftwaffe's systems, primarily comprising the series of Telefunken Funk-Gerät (or FuG) 203 Kehl twin-axis, single joystick-equipped transmitters mounted in the deploying aircraft, and Telefunken's companion FuG 230 Straßburg receiver placed in the ordnance to be controlled during deployment and used by both the Fritz X unpowered, armored anti-ship bomb, and the powered Henschel Hs 293 guided bomb, was greatly reduced by British efforts to jam their radio signals, eventually with American assistance. After initial successes, the British launched a number of commando raids to collect the missile radio sets. Jammers were then installed on British ships, and the weapons basically 'stopped working'. The German development teams then turned to wire guidance once they realized what was going on, but the systems were not ready for deployment until the war had already moved to France.