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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 ...
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 ...
The height above average terrain for VHF and higher frequencies is extremely important when considering ERP, as the signal coverage (broadcast range) produced by a given ERP dramatically increases with antenna height. Because of this, it is possible for a station of only a few hundred watts ERP to cover more area than a station of a few ...
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 ...
Antenna directivity is the ratio of maximum radiation intensity (power per unit surface) radiated by the antenna in the maximum direction divided by the intensity radiated by a hypothetical isotropic antenna radiating the same total power as that antenna. For example, a hypothetical antenna which had a radiated pattern of a hemisphere (1/2 ...
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.
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For transmissions in the shortwave range, there is little to be gained by raising the antenna more than a half to three quarters of a wavelength above ground level, and at lower frequencies and longer wavelengths, the height becomes infeasibly great (greater than 85 metres (279 ft)). Shortwave transmitters rarely use masts taller than about 100 ...