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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] |
Weather Modification
Weather modification is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding, which increases rain or snow, usually for the purpose of increasing the local water supply. Weather modification can also have the goal of preventing damaging weather, such as hail or hurricanes, from occurring; or of provoking damaging weather against the enemy, as a tactic of military or economic warfare like Operation Popeye, where clouds were seeded to prolong the monsoon in Vietnam. Weather modification in warfare has been banned by the United Nations under the Environmental Modification Convention. History A popular belief in Northern Europe that shooting prevents hail caused many agricultural towns to fire cannons without ammunition. Veterans of the Seven Years' War, Napoleonic wars, and the American Civil War reported that rain fell after every large battle. After their stories were collected in ''War and Weather'', the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equivalent Isotropically Radiated Power
Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power, such as that emitted by a radio transmitter. It is the total power in watts that would have to be radiated by a half-wave dipole antenna to give the same radiation intensity (signal strength or power flux density in watts per square meter) as the actual source antenna at a distant receiver located in the direction of the antenna's strongest beam (main lobe). ERP measures the combination of the power emitted by the transmitter and the ability of the antenna to direct that power in a given direction. It is equal to the input power to the antenna multiplied by the gain of the antenna. It is used in electronics and telecommunications, particularly in broadcasting to quantify the apparent power of a broadcasting station experienced by listeners in its reception area. An alternate parameter that measures the same thing is effec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WWVH
WWVH is the callsign of the U.S. National Institute of Standards and Technology's shortwave radio time signal station located at the Barking Sands Missile Range, in Kekaha, on the island of Kauai in the state of Hawaii. WWVH is the Pacific sister station to WWV, and has a similar broadcast format. Like WWV, WWVH's main function is the dissemination of official U.S. Government time, through exactly the same methods as found on WWV's signal. To minimize interference with the WWV broadcasts on the same frequencies, WWVH's broadcasts on 5, 10 and 15 MHz are directional, pointed primarily west. Despite this strategy, in certain places, particularly on the west coast of North America; and at certain times, due to ionospheric conditions, the listener can actually hear both WWV and WWVH on the same frequency at the same time. The information modulated on the carrier is modified to reduce confusion if both are received simultaneously. In particular, voice announcements on on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Novaya Zemlya
Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, considered the easternmost point of Europe. To Novaya Zemlya's west lies the Barents Sea and to the east is the Kara Sea. Novaya Zemlya consists of two main islands, the northern Severny Island and the southern Yuzhny Island, which are separated by the Matochkin Strait. Administratively, it is incorporated as Novaya Zemlya District, one of the twenty-one in Arkhangelsk Oblast, Russia.Law #65-5-OZ Municipally, it is incorporated as Novaya Zemlya Urban Okrug.Law #258-vneoch.-OZ The population of Novaya Zemlya as of the 2010 Census was about 2,429, of whom 1,972 resided in Belushya Guba, an urban settlement that is the administrative center of Novaya Zemlya District. The indigenous population (from 1872 to the 1950s when it was resett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baikonur Cosmodrome
The Baikonur Cosmodrome ( kk, Байқоңыр ғарыш айлағы, translit=Baiqoñyr ğaryş ailağy, ; russian: Космодром Байконур, translit=Kosmodrom Baykonur, ) is a spaceport in an area of southern Kazakhstan leased to Russia. The Cosmodrome is the world's first spaceport for orbital and human launches and the largest (in area) operational Spaceport, space launch facility. All crewed Russian spaceflights are launched from Baikonur. The spaceport is in the Kazakh Steppe, desert steppe of Baikonur, about east of the Aral Sea and north of the river Syr Darya. It is near the Tyuratam railway station and is about above sea level. The spaceport is currently leased by the Government of Kazakhstan, Kazakh Government to the Russian Federation until 2050 and is managed jointly by the Roscosmos State Corporation, Roscosmos and the Russian Aerospace Forces. The shape of the area leased is an ellipse, measuring east–west by north–south, with the cosmodrome at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mykolaiv
Mykolaiv ( uk, Миколаїв, ) is a List of cities in Ukraine, city and List of hromadas of Ukraine, municipality in Southern Ukraine, the Administrative centre, administrative center of the Mykolaiv Oblast. Mykolaiv city, which provides Ukraine with access to the Black Sea, is the location of the most downriver bridge crossing of the Southern Bug river. This city is one of the main shipbuilding centers of the Black Sea. Aside from three shipyards within the city, there are a number of research centers specializing in shipbuilding such as the State Research and Design Shipbuilding Center, Zoria-Mashproekt and others. As of 2021, the city has a population of Mykolaiv holds the honorary title Hero City of Ukraine. The city serves as a transportation hub for Ukraine, containing a sea port, commercial port, river port, highway, Junction (rail), railway junction, and airport. Much of Mykolaiv's land area consists of Park, parks. Park Peremohy (''Victory'') is a large park on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Warning Satellite
An early warning satellite is a satellite designed to rapidly detect ballistic missile launches and thus enable defensive military action. To do this, these satellites use infrared detectors that identify the missile thanks to the heat given off by its engines during the propulsion phase. This type of satellite was developed in the 1960s in the context of the Cold War in order to activate early warning systems in the target territories of a missile attack. It later became a component of missile defense systems, as well as regulatory control systems for nuclear tests. Only the two main nuclear powers, Russia and the United States, have a constellation of early warning satellites. Description The objective of an early warning satellite is to detect the launch of a ballistic missile at the beginning of its trajectory, when its detection is possible since its propulsion system gives off heat. For a typical ICBM fired from a distance of 10,000 km, this propulsive phase lasts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-ballistic Missile
An anti-ballistic missile (ABM) is a surface-to-air missile designed to counter ballistic missiles (missile defense). Ballistic missiles are used to deliver nuclear weapon, nuclear, Chemical weapon, chemical, Bioagent, biological, or conventional weapon, conventional warheads in a ballistics, ballistic flight trajectory. The term "anti-ballistic missile" is a generic term conveying a system designed to intercept and destroy any type of ballistic threat; however, it is commonly used for systems specifically designed to counter intercontinental ballistic missiles (ICBMs). Current counter-ICBM systems There are a limited number of systems worldwide that can intercept intercontinental ballistic missiles: * The Russian A-135 anti-ballistic missile system (renamed in 2017 to A-235) is used for the defense of Moscow. It became operational in 1995 and was preceded by the A-35 anti-ballistic missile system. The system uses ABM-4 Gorgon, Gorgon and Gazelle (missile), Gazelle missiles pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissolution Of The Soviet Union
The dissolution of the Soviet Union, also negatively connoted as rus, Разва́л Сове́тского Сою́за, r=Razvál Sovétskogo Soyúza, ''Ruining of the Soviet Union''. was the process of internal disintegration within the Soviet Union (USSR) which resulted in the end of the country's and its federal government's existence as a sovereign state, thereby resulting in its constituent republics gaining full sovereignty on 26 December 1991. It brought an end to General Secretary Mikhail Gorbachev's (later also President) effort to reform the Soviet political and economic system in an attempt to stop a period of political stalemate and economic backslide. The Soviet Union had experienced internal stagnation and ethnic separatism. Although highly centralized until its final years, the country was made up of fifteen top-level republics that served as homelands for different ethnicities. By late 1991, amid a catastrophic political crisis, with several republics alre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam Steering
Beam steering is a technique for changing the direction of the main lobe of a radiation pattern. In radio and radar systems, beam steering may be accomplished by switching the antenna elements or by changing the relative phases of the RF signals driving the elements. In recent days the beam steering is playing significant role in 5G communication because of quasi-optic nature of 5G frequencies. In acoustics, beam steering is used to direct the audio from loudspeakers to a specific location in the listening area. This is done by changing the magnitude and phase of two or more loudspeakers installed in a column where the combined sound is added and cancelled at the required position. Commercially, this type of loudspeaker arrangement is known as a line array. This technique has been around for many years but since the emergence of modern Digital Signal Processing technology there are now many commercially available products on the market. Beam steering and directivity Control u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Frequency
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters). Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or " skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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