Changes

[[File:lighterstill.jpg]][[File:Reiki_Radar.jpg|right|frame]]

[[File:lighterstill.jpg]][[File:Reiki_Radar.jpg|right|frame]]

*[http://en.wikipedia.org/wiki/1941 1941]

*[https://en.wikipedia.org/wiki/1941 1941]

==Definitions==

==Definitions==

*1: a device or [[system]] consisting usually of a [[synchronized]] radio [[transmitter]] and receiver that emits [http://en.wikipedia.org/wiki/Radio_waves radio waves] and processes their [[reflections]] for display and is used especially for detecting and locating objects (as aircraft) or [[surface]] features (as of a [[planet]])

*1: a device or [[system]] consisting usually of a [[synchronized]] radio [[transmitter]] and receiver that emits [https://en.wikipedia.org/wiki/Radio_waves radio waves] and processes their [[reflections]] for display and is used especially for detecting and locating objects (as aircraft) or [[surface]] features (as of a [[planet]])

*2: range of notice <fell off the radar after losing their first three games>  

*2: range of notice <fell off the radar after losing their first three games>  

==Description==

==Description==

'''Radar''' is an object-detection [[system]] which uses [[electromagnetic]] [[waves]]—specifically [http://en.wikipedia.org/wiki/Radio_wave radio waves]—to determine the range, altitude, direction, or [[speed]] of both moving and fixed objects such as aircraft, ships, spacecraft, guided missiles, motor vehicles, [[weather]] formations, and terrain. The radar dish, or antenna, [[transmits]] [[pulse]]s of radio waves or microwaves which bounce off any object in their [[path]]. The object returns a tiny part of the [[wave]]'s [[energy]] to a dish or antenna which is usually located at the same site as the transmitter.

'''Radar''' is an object-detection [[system]] which uses [[electromagnetic]] [[waves]]—specifically [https://en.wikipedia.org/wiki/Radio_wave radio waves]—to determine the range, altitude, direction, or [[speed]] of both moving and fixed objects such as aircraft, ships, spacecraft, guided missiles, motor vehicles, [[weather]] formations, and terrain. The radar dish, or antenna, [[transmits]] [[pulse]]s of radio waves or microwaves which bounce off any object in their [[path]]. The object returns a tiny part of the [[wave]]'s [[energy]] to a dish or antenna which is usually located at the same site as the transmitter.

The [[military]] applications of radar were developed in [[secret]] in nations across the world during [[World War II]]. The term ''RADAR'' was coined in 1940 by the [http://en.wikipedia.org/wiki/U.S._Navy U.S. Navy] as an acronym for radio detection and ranging. The term radar has since entered the [[English]] and other languages as the common noun radar, losing all capitalization. In the United Kingdom, the technology was initially called ''RDF'' (range and direction finding), using the same initials used for radio direction finding to conceal its ranging capability.

The [[military]] applications of radar were developed in [[secret]] in nations across the world during [[World War II]]. The term ''RADAR'' was coined in 1940 by the [https://en.wikipedia.org/wiki/U.S._Navy U.S. Navy] as an acronym for radio detection and ranging. The term radar has since entered the [[English]] and other languages as the common noun radar, losing all capitalization. In the United Kingdom, the technology was initially called ''RDF'' (range and direction finding), using the same initials used for radio direction finding to conceal its ranging capability.

The [[modern]] uses of radar are highly [[diverse]], including air traffic [[control]], [http://en.wikipedia.org/wiki/Radar_astronomy radar astronomy], air-defense systems, antimissile systems; nautical radars to locate landmarks and other ships; aircraft anticollision systems; [[ocean]]-[[surveillance]] systems, outer-[[space]] surveillance and rendezvous systems; meteorological precipitation monitoring; altimetry and flight-control systems; guided-missile target-locating systems; and ground-penetrating radar for geological [[observations]]. High tech radar systems are associated with digital signal processing and are capable of extracting objects from very high [[noise]] levels.

The [[modern]] uses of radar are highly [[diverse]], including air traffic [[control]], [https://en.wikipedia.org/wiki/Radar_astronomy radar astronomy], air-defense systems, antimissile systems; nautical radars to locate landmarks and other ships; aircraft anticollision systems; [[ocean]]-[[surveillance]] systems, outer-[[space]] surveillance and rendezvous systems; meteorological precipitation monitoring; altimetry and flight-control systems; guided-missile target-locating systems; and ground-penetrating radar for geological [[observations]]. High tech radar systems are associated with digital signal processing and are capable of extracting objects from very high [[noise]] levels.

Other systems similar to radar have been used in other parts of the [[electromagnetic]] [[spectrum]]. One example is "lidar", which uses visible [[light]] from [[lasers]] rather than [http://en.wikipedia.org/wiki/Radio_waves radio waves].[http://en.wikipedia.org/wiki/Radar]

Other systems similar to radar have been used in other parts of the [[electromagnetic]] [[spectrum]]. One example is "lidar", which uses visible [[light]] from [[lasers]] rather than [https://en.wikipedia.org/wiki/Radio_waves radio waves].[https://en.wikipedia.org/wiki/Radar]

[[Category: Physics]]

[[Category: Physics]]