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For most antennas the boresight is the axis of symmetry of the antenna. For example, for axial-fed dish antennas, the antenna boresight is the axis of symmetry of the parabolic dish, and the antenna radiation pattern (the main lobe) is symmetrical about the boresight axis. Most antennas boresight axis is fixed by their shape and cannot be changed.
A visual representation of a vertical antenna's blind cone. In telecommunications, antenna blind cone (sometimes called a cone of silence or antenna blind spot) is the volume of space, usually approximately conical with its vertex at the antenna, that cannot be scanned by an antenna because of limitations of the antenna radiation pattern and mount.
The top shows the directive pattern of a horn antenna, the bottom shows the omnidirectional pattern of a simple vertical dipole antenna. In the field of antenna design the term radiation pattern (or antenna pattern or far-field pattern) refers to the directional (angular) dependence of the strength of the radio waves from the antenna or other ...
Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis. Antenna gain (G) is defined as antenna efficiency (e) multiplied by antenna directivity (D) which is expressed mathematically as: =.
Werner reported audited net sales of $472.3 million for the year ending Dec. 31, 2005. As of March 31, 2006, Werner reported assets of $201 million and liabilities of $473.4 million. [ 3 ] Werner Co. filed for Chapter 11 protection under the bankruptcy code in Delaware on June 12, 2006, primarily due to excessive leverage, significant increases ...
With no matching unit, Varney specified 75 Ω cable be used at the junction of the ladder line and coax (not 50 Ω); the higher 75 Ω impedance makes a closer match the end of the ladder line. An earth-grounded 4:1 voltage balun may be used to connect the coax to the ladder line, and 1:1 current balun should be used between the coax and the ...
The antenna is resonant at this length, so its input impedance is purely resistive. The input impedance has capacitive reactance below 1 / 4 λ and inductive reactance from 1 / 4 to 1 / 2 λ. The gains given in this section are only achieved if the antenna is mounted over a perfectly conducting infinite ground plane ...
An ideal monopole antenna radiates maximum power in horizontal directions at a height of 225 electrical degrees, about 5 / 8 or 0.625 of a wavelength (this is an approximation valid for a typical finite thickness mast; for an infinitely thin mast the maximum occurs at / = 0.637 [6]) As shown in the diagram, at heights below a half ...