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Encyclopedia > Above mean sea level

The term above mean sea level (AMSL) refers to the elevation (on the ground) or altitude (in the air) of any object, relative to the average sea level. AMSL is used extensively in radio (both in broadcasting and other telecommunications uses) by engineers to determine the coverage area a station will be able to reach. It is also used in aviation, all heights are recorded and reported with respect to AMSL (though also see flight level). Basic Definition In geography, the elevation of a geographic location is its height above mean sea level (or some other fixed point). ... Altitude is the elevation of an object from a known level or datum. ... AIR is a three-letter abbreviation with multiple meanings, as described below: The Annals of Improbable Research, a monthly magazine devoted to scientific humour All India Radio - Indias Government Radio service AIR, a popular electronica band from France. ... In mathematics, there are numerous methods for calculating the average or central tendency of a list of n numbers. ... For considerations of sea level change, in particular rise associated with possible global warming, see sea level rise. ... individually-donated time and energy direct government payments or operation indirect government payments, such as radio and television licenses grants from foundations or business entities selling advertising or sponsorship public subscription or membership fees charged to all owners of TV sets or radios, regardless of whether they intend to receive... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... Look up engineer in Wiktionary, the free dictionary. ... Coverage has a number of meanings: It can be the state of being covered, by insurance, cell phone connectivity(more accurately and generic - radio frequency(RF)) or other service that is selectively available, depending on a factor such as location. ... Area is a physical quantity expressing the size of a part of a surface. ... First flight, December 17, 1903 Aviation or air transport refers to the activities surrounding human flight and the aircraft industry. ... In aviation, a flight level is the nominal altitude of an aircraft referenced to a standard pressure datum, as opposed to the real altitude above mean sea level. ...


When referring to geographic features such as mountains on a topographic map, variations in elevation are shown by contour lines. The elevation of a mountain denotes the highest point or summit and is typically illustrated as a small circle on a topo map with the AMSL height shown in either metres or feet or both. Geography (from the Greek words Ge (γη) or Gaea (γαια), both meaning Earth, and graphein (γραφειν) meaning to describe or to write) is the study of the Earth and its features and of the distribution of life on the earth, including human life and the effects of human activity [1]. There are at... Mount McKinley (Denali) in Alaska (USA) has the highest visible base-to-summit elevation on Earth (approximately 5400 metres). ... It has been suggested that Topographic profile be merged into this article or section. ... Elevation contour map A contour line (also level set, isopleth, isogram or isarithm) for a function of two variables is a curve connecting points where the function has a same particular value. ... Height is a measurement of the distance from the bottom to the top of something which is upright. ... metre or meter, see meter (disambiguation) A metre or meter[1] (symbol: m) is a unit of length and the current base unit of length in the International System of Units (SI). ... A foot (plural: feet) is any of several old units of distance or length, measuring around a quarter to a third of a meter. ...


The height above average terrain (HAAT) for a station is determined from topographic maps by averaging the elevation AMSL at points along several radials or radii. This is subtracted from the elevation AMSL of the antenna, including both the tower itself and the ground it is on, to determine the difference. HAAT is used extensively in radio, as it is actually much more important than power. ... To meet Wikipedias quality standards and appeal to a wider international audience, this article may require cleanup. ... A radial is a line drawn along a vector. ... In classical geometry, a radius of a circle or sphere is any line segment from its center to its boundary. ... A yagi antenna Most simply, an antenna is an electronic component designed to send or receive radio waves. ... The Eiffel Tower Fire-observation watchtower in Kostroma, Russia. ...


Negative numbers for HAAT sometimes result from this when the station or airport is in a valley, which is significantly lower AMSL than the surrounding mountains. In the rare case that a location is below sea level, AMSL itself is a negative number. For one such case see Schiphol Airport. A negative number is a number that is less than zero, such as −3. ... Fljótsdalur in East-Iceland A valley is a landform, which can range from a few square miles (square kilometers) to hundreds or even thousands of square miles (square kilometers) in area. ... Schiphol (IATA: AMS, ICAO: EHAM) (municipality Haarlemmermeer) is the Netherlands main airport. ...


AMSL is also important to engineers in high-elevation areas because some equipment is not designed with enough airflow for sufficient cooling in the thin air, which can cause overheating, damage, and failure of the electronic components within a transmitter. Fatale is also the title of a comic book published in the mid-1990s by Broadway Comics. ... Look up failure in Wiktionary, the free dictionary. ... Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...


It should be noted that the concept of a "mean sea level" is in itself rather artificial, because it is not possible to determine a figure for mean sea level for the entire planet, and it varies quite a lot even on a much smaller scale. This is because the sea is in constant motion, affected by the high and low pressure zones above it, the tides, local gravitational differences, and so forth. The best one can do is to pick a spot and calculate the mean sea level at that point and use it as a datum. For example, the Ordnance Survey uses a height datum based on the mean sea level of a particular gauge at Newlyn, Cornwall for their maps of Great Britain, and this datum is actually some 80cm different from the mean sea level reading obtained on the other side of the country. An alternative is to base height measurements on an ellipsoid of the entire earth, which is what systems such as GPS do. In aviation, the ellipsoid known as World Geodetic System 84 is increasingly used to define mean sea level. It has been suggested that this article or section be merged with Geodetic system. ... Image produced from the Ordnance Survey Get-a-map service. ... Newlyn Map sources for Newlyn at grid reference SW461284 Newlyn (Cornish: Lulynn) is a town in southwest Cornwall, UK. The town forms a small conurbation with neighbouring Penzance, and part of the civil parish of Penzance. ... Cornish Flag Cornwall (Cornish: Kernow) is a county in South West England on the peninsula that lies to the west of the River Tamar. ... 3D rendering of an ellipsoid In mathematics, an ellipsoid is a type of quadric that is a higher dimensional analogue of an ellipse. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... The World Geodetic System defines a fixed global reference frame for the Earth, for use in geodesy and navigation. ...


For sample elevations, see 1 E3 m, list of mountains, Ranges, peaks and passes of the Alps. To help compare different orders of magnitude this page lists lengths between 1 km and 10 km (103 and 104 m). ... . ... The West face of the Petit Dru above the Chamonix valley near the Mer de Glace. ...


  Results from FactBites:
 
Above mean sea level - Wikipedia, the free encyclopedia (510 words)
The height above average terrain (HAAT) for a station is determined from topographic maps by averaging the elevation AMSL at points along several radials or radii.
This is subtracted from the elevation AMSL of the antenna, including both the tower itself and the ground it is on, to determine the difference.
AMSL is also important to engineers in high-elevation areas because some equipment is not designed with enough airflow for sufficient cooling in the thin air, which can cause overheating, damage, and failure of the electronic components within a transmitter.
Sea level - Wikipedia, the free encyclopedia (940 words)
Mean sea level (MSL) is the average (mean) height of the sea, with reference to a suitable reference surface.
Mean sea level at the Pacific end of the Panama Canal stands 20 cm higher than at the Atlantic end.
The subsidence of land due to the withdrawal of groundwater is an isostatic cause of relative sea level rise.
  More results at FactBites »

 
 

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