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Delimara Transmitter
The Delimara Transmitter was a Broadcast relay station, relay station of Deutsche Welle near Cyclops on Malta. It was used as Shortwave radio, short- and medium wave Transmission (telecommunications), transmission site. For the medium wave transmissions, which took place on 1557 hertz, kHz with a transmission power of 600 watt, kW, it had two guyed masts, insulated against ground, which were guyed with polymeric Guy-wire, guyes. The short wave antennas were mounted on free-standing lattice towers. Direction was achieved by different slewing of the various antennae available. Originally, the medium wave antenna consisted of three masts, each 88 metres tall, but at one mast one (Parafil) guy melted as a result of the high electric field values halfway up from the anchor point. Unfortunately there was also a storm at this time, which resulted in mast collapse. This was later replaced. Delimara Transmitter was shut down in 1996. The site is now a nature reserve. References Sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymeric
A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals. The term "polymer" derives from the Greek word πολύς (''polus'', meaning "many, much") and μέρος (''meros'', meaning "pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Towers In Malta
A tower is a tall structure, taller than it is wide, often by a significant factor. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures. Towers are specifically distinguished from buildings in that they are built not to be habitable but to serve other functions using the height of the tower. For example, the height of a clock tower improves the visibility of the clock, and the height of a tower in a fortified building such as a castle increases the visibility of the surroundings for defensive purposes. Towers may also be built for observation, leisure, or telecommunication purposes. A tower can stand alone or be supported by adjacent buildings, or it may be a feature on top of a larger structure or building. Etymology Old English ''torr'' is from Latin ''turris'' via Old French ''tor''. The Latin term together with Greek τύρσις was loaned from a pre-Indo-European Mediterranean langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsaxlokk
Marsaxlokk () is a small, traditional fishing village in the South Eastern Region of Malta. It has a harbour, and is a tourist attraction known for its views, fishermen and history. As at March 2014, the village had a population of 3,534. The village is also known for the Marsaxlokk Market, which is mainly a large fish market which takes place along the seafront on Sundays, and a tourist market during all other days of the week. Inhabited and well-known since antiquity, Marsaxlokk was used as a port by Phoenicians, Carthaginians and also has the remains of a Roman-era harbour. Originally a part of the city of Żejtun, the fishing village became a separate parish in the late nineteenth century. Traditional luzzi and other larger and more modern vessels line the sheltered inner harbour. The village is also popular among locals and tourists alike for its walks around the coast and harbour, its restaurants, as well as for its swimming zones. Marsaxlokk Bay also includes a contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications In Malta
This article is an overview of telecommunications in Malta. Telephone Telephones - main lines in use: 229,700 (2012) Telephones - mobile cellular: 539,500 (2012) Telephone system: automatic system satisfies normal requirements ''domestic:'' submarine cables and microwave radio relay between islands ''international:'' 2 submarine cables; satellite earth station - 1 Intelsat (Atlantic Ocean) Radio Radio broadcast stations: AM 1, FM 18, shortwave 6 (1999) Radios: 255,000 (1997) Amateur radio operators: Approx. 500 Amateur radio repeaters: 1 HF ALE EchoLink Gateway (9H1BBS-L) DTMF Access 145300 CTCSS 77 Hz (Owned by G0DEO/9H1IA) 1 VHF/UHF 9H1IA-L Frequency Agile CrossBand Link CTCSS 151.4 Hz (Owned by G0DEO/9H1IA) 1 VHF (9H1BBS 145.750 MHz CTCSS 77 Hz (Owned by G0DEO/9H1IA) 1 UHF (9H1BBS 433.175 MHz CTCSS 77 Hz (Owned by G0DEO/9H1IA) 2 Microwave Amateur Television ( ATV ) Repeaters ( 9H1ATV built by 9H1LO and run by MARL and 9H1LO/r built and run ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Broadcast Transmitters
Broadcasting is the distribution of audio or video content to a dispersed audience via any electronic mass communications medium, but typically one using the electromagnetic spectrum (radio waves), in a one-to-many model. Broadcasting began with AM radio, which came into popular use around 1920 with the spread of vacuum tube radio transmitters and receivers. Before this, all forms of electronic communication (early radio, telephone, and telegraph) were one-to-one, with the message intended for a single recipient. The term ''broadcasting'' evolved from its use as the agricultural method of sowing seeds in a field by casting them broadly about. It was later adopted for describing the widespread distribution of information by printed materials or by telegraph. Examples applying it to "one-to-many" radio transmissions of an individual station to multiple listeners appeared as early as 1898. Over the air broadcasting is usually associated with radio and television, though more r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lattice Tower
A lattice tower or truss tower is a freestanding vertical framework tower. This construction is widely used in transmission towers carrying high voltage electric power lines, in radio masts and towers (a self-radiating tower or as a support for aerials) and in observation towers. Its advantage is good shear strength at a much lower weight than a tower of solid construction would have as well as lower wind resistance. In structural engineering the term ''lattice tower'' is used for a freestanding structure, while a ''lattice mast'' is a guyed mast supported by guy lines. Lattices of triangular (3-sided) cross-section are most common, particularly in North America. Square (4-sided) lattices are also widely used and are most common in Eurasia. Lattice towers are often designed as either a space frame or a hyperboloid structure. Before 1940, they were used as radio transmission towers especially for short and medium wave. Occasionally lattice towers consisting of wood were utilized. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guy-wire
A guy-wire, guy-line, guy-rope, or stay, also called simply a guy, is a tensioned cable designed to add stability to a free-standing structure. They are used commonly for ship masts, radio masts, wind turbines, utility poles, and tents. A thin vertical mast supported by guy wires is called a guyed mast. Structures that support antennas are frequently of a lattice construction and are called "towers". One end of the guy is attached to the structure, and the other is anchored to the ground at some distance from the mast or tower base. The tension in the diagonal guy-wire, combined with the compression and buckling strength of the structure, allows the structure to withstand lateral loads such as wind or the weight of cantilevered structures. They are installed radially, usually at equal angles about the structure, in trios and quads. As the tower leans a bit due to the wind force, the increased guy tension is resolved into a compression force in the tower or mast and a late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guyed Mast
A guyed mast or guyed tower is a tall thin vertical structure that depends on guy lines (diagonal tensioned cables attached to the ground) for stability. The mast itself has the compressive strength to support its own weight, but does not have the shear strength to stand unsupported. It requires guy lines to stay upright and to resist lateral forces such as wind loads. Guy lines are usually spaced at equal angles about the structure's base. Guyed masts are used for telecommunications, sailing, and meteorology. The tallest guyed mast in the world is currently the KVLY-TV mast near Blanchard, North Dakota, USA. Two subtypes exist. A ''partially guyed tower'' is a structure consisting of a guyed mast on top of a freestanding tower. The guys may be anchored to the top of the freestanding structure, or to the ground. A famous tower of this type is the Gerbrandy Tower. An ''additionally guyed tower'' is a freestanding tower which either has guys attached temporarily to add stab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. It expands 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. However, depending on technical and regulatory restrictions, relays may also be set up by unrelated organisations. Types Broadcast translators In its simplest form, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Watt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Watt (1736–1819), an 18th-century Scottish inventor, mechanical engineer, and chemist who improved the Newcomen engine with his own steam engine in 1776. Watt's invention was fundamental for the Industrial Revolution. Overview When an object's velocity is held constant at one metre per second against a constant opposing force of one newton, the rate at which work is done is one watt. : \mathrm In terms of electromagnetism, one watt is the rate at which electrical work is performed when a current of one ampere (A) flows across an electrical potential difference of one volt (V), meaning the watt is equivalent to the volt-ampere (the latter unit, however, is used for a different quantity from the real power of an electrical circuit). : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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