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The antenna used for broadcasting through the 1920s was the T-antenna, which consisted of two masts with loading wires on top, strung between them, requiring twice the construction costs and land area of a single mast. [2] (pp 77–78) In 1924 Stuart Ballantine published two historic papers which led to the development of the single mast antenna.
A quad antenna is a self-resonant loop in a square shape; this one also includes a parasitic element.. Loop antennas may be in the shape of a circle, a square, or any other closed geometric shape that allows the total perimeter to be slightly more than one wavelength.
The mast is resonant at the lengths where the reactance goes to zero. In an ideal thin monopole antenna these would be at a length of 0.25 λ {\displaystyle 0.25\lambda } anf 0.5 λ {\displaystyle 0.5\lambda } . but in actual mast radiators as shown here the thickness of the mast, and capacitance of guy wires and the base insulator causes ...
AN-SOF - A Windows simulation software for antennas in free space and above a lossy ground, microstrip patch antennas and printed circuit boards (PCBs). A radial wire ground screen is included and connections to imperfect ground are allowed. Not based on NEC. AutoEZ - An Excel application that works in conjunction with EZNEC v.5.0 & v.6.0 ...
A modified mast antenna, usually grounded at its base, augmented by one or several parallel wires called "skirt wires" that attach to the mast part-way up the antenna. The skirt wires can attach at any height between part-way up and the top of the mast. One or more of the skirt wires is fed with the signal, similar to a gamma match.
This simplified arrangement has several advantages, including a shorter ground distance between the ends. For example, a dipole antenna for the 80 meter band requires a ground length of about 140 feet (43 m) from end to end. An inverted vee with a 40-foot (12 m) apex elevation requires only 115 feet (35 m).
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: =.
In 1938, George Brown et al. patented a loop antenna with rhombic shape and quarterwave sides. [2] In 1951 Clarence C. Moore, W9LZX, a Christian missionary and engineer at HCJB (a shortwave missionary radio station high in the Andean Mountains) developed and patented [3] a two-turn loop antenna which he called a "quad".