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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.
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.
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 ]
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 size of the range that is required can be much less than the size required for a full-size far-field anechoic chamber, although the cost of fabrication of the specially-designed CATR reflector can be expensive due to the need to ensure precision of the reflecting surface (typically less than 1 / 100 λ RMS surface accuracy) and to ...
The quarter-wave monopole, the most compact resonant antenna, may be the most widely used antenna in the world. The five-eighth wave monopole – length 0.625 λ , or 5 / 8 of a wavelength – is also popular, since at that length monopoles direct the greatest proportion of their radiated power horizontally, hence the best use of ...
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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 ...