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Cobra Mist
Cobra Mist was the codename for an Anglo-American experimental over-the-horizon radar station at Orford Ness, England. It was known technically as AN/FPS-95 and sometimes referred to as System 441a; a reference to the project as a whole. Cobra Mist was part of a small number of "Cobra" long-range surveillance radars operated by the U.S. Cobra Mist was originally intended to be mounted in Turkey and offer coverage of most of European Soviet airspace. When Turkey objected to the site it was moved to the UK and sited to offer a view of most of Eastern Europe. Built through the late 1960s and into 1970, when the system was first turned on it proved to be plagued by noise problems that could not be identified and the project was shut down in 1973. The site and buildings were then occupied by a radio transmitting station used mainly for the UK Foreign Office and the BBC World Service until 2011. In August 2015 the site and all the facilities previously held by the UK Foreign Office a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesetsk
Plesetsk (russian: Плесе́цк) is an urban locality (a work settlement) and the administrative center of Plesetsky District, Arkhangelsk Oblast, Russia, situated about northeast of Moscow and south of Arkhangelsk. Municipally, it is the administrative center of Plesetskoye Urban Settlement, one of eight urban settlements in the district. Population: The vast Plesetsk Cosmodrome territory is located nearby and is administered from the town of Mirny which is away from Plesetsk. The territory also includes the Plestsy Airport. Etymology The name is derived from the word "" (''plyos'') which means "river reach". Plestsy is the name for a small lake which Plesetsk adjoins. History The area was populated by speakers of Uralic languages and then colonized by the Novgorod Republic. It belonged at the trading routes connecting central and northern Russia: first, from Moscow to the White Sea along the Onega River, and then, after 1765, along the newly built road between Sai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Equipment Introduced In The 1970s
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct military uniform. It may consist of one or more military branches such as an army, navy, air force, space force, marines, or coast guard. The main task of the military is usually defined as defence of the state and its interests against external armed threats. In broad usage, the terms ''armed forces'' and ''military'' are often treated as synonymous, although in technical usage a distinction is sometimes made in which a country's armed forces may include both its military and other paramilitary forces. There are various forms of irregular military forces, not belonging to a recognized state; though they share many attributes with regular military forces, they are less often referred to as simply ''military''. A nation's military may f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Over-the-horizon Radars
Over-the-horizon radar (OTH), sometimes called beyond the horizon radar (BTH), is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is the distance limit for ordinary radar. Several OTH radar systems were deployed starting in the 1950s and 1960s as part of early warning radar systems, but these have generally been replaced by airborne early warning systems. OTH radars have recently been making a comeback, as the need for accurate long-range tracking becomes less important with the ending of the Cold War, and less-expensive ground-based radars are once again being considered for roles such as maritime reconnaissance and drug enforcement. Technology The frequency of radio waves used by most radars, in the form of microwaves, travel in straight lines. This generally limits the detection range of radar systems to objects on their horizon (generally referred to as "line of sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Radars
Ground may refer to: Geology * Land, the surface of the Earth not covered by water * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical circuit from which voltages are measured * Earthing system, part of an electrical installation that connects with the Earth's conductive surface * Ground and neutral, closely related terms Law * Ground (often grounds), in law, a rational motive or basis for a belief, conviction, or action taken, such as a legal action or argument: * Grounds for divorce, regulations specifying the circumstances under which a person will be granted a divorce Music * ''Ground'' (album), the second album by the Nels Cline Trio * "Ground" (song), one of the songs in the debut album of the Filipino rock band Rivermaya * Ground bass, in music, a bass part that continually repeats, while the melody and harmony over it change * ''The Ground'', a 2005 album by Nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold War Military Radars Of The United States
Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00K on the Kelvin scale, an absolute thermodynamic temperature scale. This corresponds to on the Celsius scale, on the Fahrenheit scale, and on the Rankine scale. Since temperature relates to the thermal energy held by an object or a sample of matter, which is the kinetic energy of the random motion of the particle constituents of matter, an object will have less thermal energy when it is colder and more when it is hotter. If it were possible to cool a system to absolute zero, all motion of the particles in a sample of matter would cease and they would be at complete rest in the classical sense. The object could be described as having zero thermal energy. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duga Radar
''Duga'' (, ) was an over-the-horizon radar (OTH) system used in the Soviet Union as part of its early-warning radar network for missile defense. It operated from July 1976 to December 1989. Two operational ''duga'' radars were deployed, with one near Chernobyl and Chernihiv in the Ukrainian SSR (present-day Ukraine), and the other in eastern Siberia (present-day Russia). The ''duga'' system was extremely powerful, reaching over 10 MW, and broadcast in the shortwave radio bands. It was given the nickname Russian Woodpecker by shortwave listeners for its emissions randomly appearing and sounding like sharp, repetitive tapping noises at a frequency of 10 Hz. The random frequency hops often disrupted legitimate broadcasts, amateur radio operations, oceanic commercial aviation communications, and utility transmissions, resulting in thousands of complaints by many countries worldwide. The signal became such a nuisance that some communications receivers began including "Woodpecker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jindalee Over-the-horizon Radar
Jindalee may refer to: * Jindalee, New South Wales * Jindalee, Queensland * Jindalee, Western Australia * Jindalee Operational Radar Network See also * ''Jindalee Lady ''Jindalee Lady'' is a 1992 Australian film about an Aboriginal Australian woman who is a successful fashion designer. Directed by Brian Syron, it is the first feature film directed by an Aboriginal person in Australia.Ed. Scott Murray, ''Austra ...'', 1990 film {{Disambiguation, place name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Effect
The Doppler effect or Doppler shift (or simply Doppler, when in context) is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach, identical at the instant of passing by, and lower during the recession. The reason for the Doppler effect is that when the source of the waves is moving towards the observer, each successive wave crest is emitted from a position closer to the observer than the crest of the previous wave. Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse Repetition Frequency
The pulse repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is turned on and off; the term "frequency" refers to the carrier, while the PRF refers to the number of switches. Both are measured in terms of cycle per second, or hertz. The PRF is normally much lower than the frequency. For instance, a typical World War II radar like the Type 7 GCI radar had a basic carrier frequency of 209 MHz (209 million cycles per second) and a PRF of 300 or 500 pulses per second. A related measure is the pulse width, the amount of time the transmitter is turned on during each pulse. After producing a brief pulse of radio signal, the transmitter is turned off in order for the receiver units to hear the reflections of that signal off distant targets. Since the radio signal has to travel out to the target and back ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
