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Shortwave Relay Station
Shortwave relay stations are transmitter sites used by international broadcasters to extend their coverage to areas that cannot be reached easily from their home state. For example, the BBC operates an extensive net of relay stations. These days the programs are fed to the relay sites by satellite, cable/optical fiber or the Internet. Frequencies, transmitter power and antennas depend on the desired coverage. Some regional relays even operate in the medium wave or FM bands. Relay stations are also important to reach listeners in countries that practice radio jamming. Depending on the effect of the shortwave dead zone the target countries can jam the programs only locally, e.g. for bigger cities. For this purpose Radio Free Europe/ Radio Liberty with studios in Munich, Germany operated a relay station in Portugal, in the extreme west of Europe, to reach then-communist Eastern Europe. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sistema HR ALLISS
AFK Sistema PAO is a large Russian conglomerate company, founded by Vladimir Yevtushenkov, who was chairman of the corporation's board of directors until 2022. In April, Yevtushenkov's shareholding in Sistema has decreased to 49.2%, and he also stepped down from Sistema's board. Sistema has its headquarters in Moscow. The company's global depository receipts (GDRs) traded on the London Stock Exchange from 2005 until delisting in May 2023. It has been under US sanctions since November 2023. History In 1993, Evgeny Novitsky and Vladimir Yevtushenkov founded the holding company AFK Sistema, also known as Sistema JSFC, to group together several information technology (IT) and cell phone companies including MTS. Structure Sistema operates a number of consumer service businesses in the areas of: * IT and telecoms — Mobile TeleSystems, Moscow City Telephone Network, SkyLink, Sitronics (formerly known as 'Science Center Concern'), NIIME, Mikron, STROM telecom. * Banking — MTS B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Log-periodic
A log-periodic antenna (LP), also known as a log-periodic array or log-periodic aerial, is a multi-element, directional antenna designed to operate over a wide band of frequencies. It was invented by John Dunlavy in 1952. The most common form of log-periodic antenna is the log-periodic dipole array or LPDA, The LPDA consists of a number of half-wave dipole driven elements of gradually increasing length, each consisting of a pair of metal rods. The dipoles are mounted close together in a line, connected in parallel to the feedline with alternating phase. Electrically, it simulates a series of two- or three-element Yagi–Uda antennas connected together, each set tuned to a different frequency. LPDA antennas look somewhat similar to Yagi antennas, in that they both consist of dipole rod elements mounted in a line along a support boom, but they work in very different ways. Adding elements to a Yagi increases its directionality, or gain, while adding elements to an LPDA increases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency Antenna Types
Radio is the technology of telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna (radio), antenna which radiates the waves. They can be received by other antennas connected to a radio receiver; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar, radio navigation, radio control, remote control, remote sensing, and other applications. 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 Modulation, modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency Propagation
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves. They can be received by other antennas connected to a radio receiver; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar, radio navigation, remote control, remote sensing, and other applications. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Broadcasting
International broadcasting consists of radio and television transmissions that purposefully cross international boundaries, often with then intent of allowing expatriates to remain in touch with their countries of origin as well as educate, inform, and influence residents of foreign countries. Content can range from overt propaganda and counterpropaganda to cultural content to news reports that reflect the point of view and concerns of the originating country or that seek to provide alternative information to that otherwise available as well as promote tourism and trade. In the first half of the twentieth century, international broadcasting was used by colonial empires as a means of connecting colonies with the metropole (for example the BBC Empire Service as well as France's Poste Colonial and the Dutch overseas radio services, PCJJ and PHOHI). When operated by governments or entities close to a government, international broadcasting can be a form of soft power. Less frequentl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperial Wireless Chain
The Imperial Wireless Chain was a strategic international communications network of powerful long range radiotelegraphy stations, created by the British government to link the countries of the British Empire. The stations exchanged commercial and diplomatic text message traffic transmitted at high speed by Morse code using paper tape machines. Although the idea was conceived prior to World War I, the United Kingdom was the last of the world's great powers to implement an operational system.Empire Wireless Papers Past, Evening Post (New Zealand), published 1923-04-23, accessed 2010-10-03 The first link in the chain, between Leafield in Oxfordshire and |
Broadcast Relay Station
A broadcast relay station, also known as a satellite station, relay transmitter, broadcast translator (U.S.), re-broadcaster (Canada), repeater ( two-way radio) or complementary station (Mexico), is a broadcast transmitter which repeats (or transponds) the signal of a radio or television station to an area not covered by the originating station. These expand the broadcast range of a television or radio station beyond the primary signal's original coverage or improves service in the original coverage area. The stations may be (but are not usually) used to create a single-frequency network. They may also be used by an AM or FM radio station to establish a presence on the other band. Relay stations are most commonly established and operated by the same organisations responsible for the originating stations they repeat. Depending on technical and regulatory restrictions, relays may also be set up by unrelated organisations. Types Translators In its simplest form, a broadcast tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio France Internationale
Radio France Internationale, usually referred to as RFI, is the State media, state-owned international radio news network of France. With 59.5 million listeners in 2022, it is one of the most-listened-to international radio stations in the world, along with Deutsche Welle, the BBC World Service and Voice of America. RFI broadcasts 24 hours per day around the world in French and in 16 other languages in FM, shortwave, medium wave, satellite and on its website. It is a channel of the state company France Médias Monde. The majority of shortwave transmissions are in French and Hausa language, Hausa but also includes some hours of Swahili language, Swahili, Fulfulde language, Fulfulde and Mandinka language, Mandinka. RFI broadcasts to over 150 countries on 5 continents. Africa is the largest part of radio listeners, representing 60% of the total audience in 2010. In the Île-de-France, Paris region, RFI comprises between 150,000 and 200,000 listeners. Its digital platforms attract an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TDF Group
TDF (which stands for ''Télédiffusion de France'' officially renamed ''TDF'' in 2004) is a French company which provides radio and television transmission services, services for telecommunications operators, and other multimedia services – digitization of content, encoding, storage, etc. Its headquarters are located in Paris. It is the dominant partner in the HDRR WiMAX consortium and is also part of Digital Radio Mondiale. Arkena Arkena was European company that regroups four entities: Cognacq-Jay Image (France), PSN (Poland), Qbrick (Sweden) and SmartJog (France). These entities were all part of the Media Services division of the TDF Group. http://www.broadbandtvnews.com/2014/01/20/arkena-joins-together-all-tdf-media-subsidiaries/ - Broadband TV News, 20 January 2014 Arkena provides f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint-Aoustrille
Saint-Aoustrille () is a commune in the Indre department in central France. It is named after the 7th-century Saint Austregisilus. Population See also *Communes of the Indre department The following is a list of the 241 communes of the Indre department of France. The communes cooperate in the following intercommunalities (as of 2025):Communes of Indre {{Indre-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Issoudun
Issoudun () is a commune in the Indre department, administrative region of Centre-Val de Loire, France. It is also referred to as ''Issoundun'', which is the ancient name. Geography Location Issoudun is a sub-prefecture, located in the east of the Indre department. It is in the former region of Berry. The surrounding communes are: * Les Bordes (4 km) * Saint-Aoustrille (5 km) * St. Lizaigne (7 km) * Chouday (7 km) * Lizeray (8 km) * Condé (8 km) * Thizay (8 km) * Saint-Georges-sur-Arnon (10 km) * Saint-Ambroix (10 km) * Saugy (10 km) * Saint-Aubin (11 km) * Châteauroux (27 km) * Châtre (41 km) * Le Blanc (79 km) Terrain The river of Théols passes through Issoudun. The commune of Issoudun takes up an area of 36.6 km2. Transport The national road N151 passes through the area. The nearest airport is the Marcel Dassault Airport, 27 km away. The Issoudun station is located at 4 Pierre Favr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Direction Finding
Direction finding (DF), radio direction finding (RDF), or radiogoniometry is the use of radio waves to determine the direction to a radio source. The source may be a cooperating radio transmitter or may be an inadvertent source, a naturally-occurring radio source, or an illicit or enemy system. Radio direction finding differs from radar in that only the direction is determined by any one receiver; a radar system usually also gives a distance to the object of interest, as well as direction. By triangulation, the location of a radio source can be determined by measuring its direction from two or more locations. Radio direction finding is used in radio navigation for ships and aircraft, to locate emergency transmitters for search and rescue, for tracking wildlife, and to locate illegal or interfering transmitters. During the Second World War, radio direction finding was used by both sides to locate and direct aircraft, surface ships, and submarines. RDF systems can be used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
