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Square keys are used for smaller shafts and rectangular faced keys are used for shaft diameters over 6.5 in (170 mm) or when the wall thickness of the mating hub is an issue. Set screws often accompany parallel keys to lock the mating parts into place. [3] The keyway is a longitudinal slot in both the shaft and mating part.
NMO mount connector (new Motorola mount), removable mobile antenna connector uses a 3 ⁄ 4 inch (19 mm) mounting hole and has a large base with a 1 1/8" – 18 tpi thread for attaching the antenna. SC connector, screw version of C connector [not to be confused with the fiber optic connector of the same name]
Sellers often claim to supply a special digital or high-definition television (HDTV) antenna advised as a replacement for an existing analog television antenna; at best this is misinformation to generate sales of unneeded equipment, [9] [10] At worst, it may leave the viewer with a UHF-only antenna in a local market (particularly in North ...
Slotted array UHF television broadcasting antenna. As shown by H. G. Booker in 1946, from Babinet's principle in optics a slot in a metal plate or waveguide has the same radiation pattern as a driven rod antenna whose rod is the same shape as the slot, with the exception that the electric field and magnetic field directions are interchanged; the antenna is a magnetic dipole instead of an ...
An isotropic antenna radiates equal power in all three dimensions, while an omnidirectional antenna radiates equal power in all horizontal directions, but little or none vertically. An omnidirectional antenna's radiated power varies with elevation angle: Maximum in the horizontal, and diminishing as the azimuth rises to align with the antenna's ...
The rubber ducky antenna (or rubber duck aerial) is an electrically short monopole antenna, invented by Richard B. Johnson, that functions somewhat like a base-loaded whip antenna. It consists of a springy wire in the shape of a narrow helix , sealed in a rubber or plastic jacket to protect the antenna. [ 1 ]
A helical antenna is an antenna consisting of one or more conducting wires wound in the form of a helix. A helical antenna made of one helical wire, the most common type, is called monofilar , while antennas with two or four wires in a helix are called bifilar , or quadrifilar , respectively.
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 ...