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Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site 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 ...
In telecommunications, the effective height of an antenna is the height of the antenna's center of radiation above the ground. In low-frequency applications involving loaded or nonloaded vertical antennas, the effective height is the moment of the current distribution in the vertical section, divided by the input current. For an antenna with a ...
The typical height of a 'T' antenna is shorter than the quarter wavelength required for resonance. A 'T' antenna is distinguished from the similar 'L' antenna by the place where the dangling, radiating wire attaches to the horizontal cross wire: For the 'T' antenna the dangling wire attaches to the exact center of the top horizontal wire.
Efficiency is the ratio of power actually radiated by an antenna to the electrical power it receives from a transmitter. A dummy load may have an SWR of 1:1 but an efficiency of 0, as it absorbs all the incident power, producing heat but radiating no RF energy; SWR is not a measure of an antenna's efficiency.
In antenna theory, radiation efficiency is a measure of how well a radio antenna converts the radio-frequency power accepted at its terminals into radiated power. Likewise, in a receiving antenna it describes the proportion of the radio wave's power intercepted by the antenna which is actually delivered as an electrical signal.
It can be used for base-station antenna heights ranging from 30–1000 m. Okumura developed a set of curves giving the median attenuation relative to free space (A mu), in an urban area over a quasi-smooth terrain with a base station effective antenna height (hte) of 200 m and a mobile antenna height (hre) of 3 m. These curves were developed ...
In electromagnetics and antenna theory, the aperture of an antenna is defined as "A surface, near or on an antenna, on which it is convenient to make assumptions regarding the field values for the purpose of computing fields at external points. The aperture is often taken as that portion of a plane surface near the antenna, perpendicular to the ...
English: Graph of the measured base feed resistance and reactance of a typical mast radiator antenna vs the height of the mast. A mast radiator antenna consists of a guyed lattice mast in which the steel mast structure itself is connected to the transmitter and functions as the antenna. It is mounted on a ceramic insulator which keeps it ...