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Height Above Average Terrain
Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site is above the surrounding landscape. HAAT is used extensively in FM radio and television, as it is more important than effective radiated power (ERP) in determining the range of broadcasts ( VHF and UHF in particular, as they are line of sight transmissions). For international coordination, it is officially measured in meters, even by the Federal Communications Commission in the United States, as Canada and Mexico have extensive border zones where stations can be received on either side of the international boundaries. Stations that want to increase above a certain HAAT must reduce their power accordingly, based on the maximum distance their station class is allowed to cover (see List of North American broadcast station classes for more information on this). The FCC procedure to calculate HAAT is: from the proposed or actual antenna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertical Position
Vertical position or vertical location, also known as vertical level or simply level, is a position along a vertical direction above or below a given vertical datum (reference level). Vertical distance or vertical separation is the distance between two vertical positions. Many vertical coordinates exist for expressing vertical position: depth, height, altitude, elevation, etc. Definitions The International Organization for Standardization (ISO), more specifically ISO 19111, offers the following two definitions: * ''depth'': "distance of a point from a chosen reference surface measured downward along a line perpendicular to that surface." * ''height'': "distance of a point from a chosen reference surface measured upward along a line perpendicular to that surface"; ISO 6709 (2008 version) makes the following additional definition: * ''altitude'': "height where the chosen reference surface is mean sea level" The International Civil Aviation Organization (ICAO) offers similar definit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-channel Interference
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same channel. Co-channel interference can be caused by many factors from weather conditions to administrative and design issues. Co-channel interference may be controlled by various radio resource management schemes. Cellular mobile networks In cellular mobile communication (GSM & LTE Systems, for instance), frequency spectrum is a precious resource which is divided into non-overlapping spectrum bands which are assigned to different cells (In cellular communications, a cell refers to the hexagonal/circular area around the base station antenna). However, after certain geographical distance, these frequency bands are re-used, i.e. the same spectrum bands are reassigned to other distant cells. The co-channel interference arises in the cellular mobile networks owing to this phenomenon of frequency reuse. Thus, besides the intended signal from within the cell, signals at the same frequenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Virginia
West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the Bureau of Labor Statistics classifies the state as a part of the Mid-Atlantic regionMid-Atlantic Home : Mid-Atlantic Information Office: U.S. Bureau of Labor Statistics" www.bls.gov. Archived. It is bordered by Pennsylvania to the north and east, Maryland to the east and northeast, Virginia to the southeast, Kentucky to the southwest, and Ohio to the northwest. West Virginia is the 10th-smallest state by area and ranks as the 12th-least populous state, with a population of 1,793,716 residents. The capital and largest city is Charleston. West Virginia was admitted to the Union on June 20, 1863, and was a key border state during the American Civil War. It was the only state to form by separating from a Confederate state, the second to sepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
