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An antenna rotator (or antenna rotor) is a device used to change the orientation, within the horizontal plane, of a directional antenna. Most antenna rotators have two parts, the rotator unit and the controller. The controller is normally placed near the equipment which the antenna is connected to, while the rotator is mounted on the antenna ...
Antennas are generally sensitive to signals only when they have a length that is a significant portion of the wavelength, or larger. Most antennas are at least 1 ⁄ 4 of the wavelength, more commonly 1 ⁄ 2 – the half-wave dipole is a very common design. For longwave use, this resulted in loop antennas tens of feet on a side, often with ...
An NVIS antenna configuration is a horizontally polarized (parallel with the surface of the earth) radiating element that is from 1 / 20 th wavelength to 1 / 4 wave above the ground. The optimum height of such an antenna is about 1 / 4 wavelength, and high angle radiation declines only slightly for heights up to about ...
This Royal Navy model is typical of B–T goniometers. The two sets of field coils and the rotating sense coil are visible.. A Bellini–Tosi direction finder (B–T or BTDF) is a type of radio direction finder (RDF), which determines the direction to, or bearing of, a radio transmitter.
This article provides a summary description of many of the different antenna types used for radio receiving or transmitting systems.
Moxon antenna for the 20-meter band.The antenna is the faint rectangle of wires held in tension by the bent X-shaped support frame. Moxon antenna for the 2-meter band. The Moxon antenna or Moxon rectangle is a simple and mechanically rugged two-element parasitic array, single-frequency antenna. [1]
A turnstile antenna, or crossed-dipole antenna, [1] is a radio antenna consisting of a set of two identical dipole antennas mounted at right angles to each other and fed in phase quadrature; the two currents applied to the dipoles are 90° out of phase. [2] [3] The name reflects the notion the antenna looks like a turnstile when mounted ...
Frequency-dependant phase shifting of the elements of the array can be used to compensate for the squint, [4] which leads to the concept of a squintless antenna or feed. [5] Design In some cases the antenna may be designed to create a squint. For example, an antenna which is used to communicate with a satellite but must remain in a vertical ...