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The ARC-190 is a military HF radio that operates between 2-30 MHz and transmits at 300+ watts.It features a dual heterodyne receiver/transmitter that uses IF frequencies of 97.8 and 1.8 MHz, an antenna coupler that is pressurized to 7±1 PSI with dry nitrogen (air) which (1) prevents high voltage arcing, (2) prevents corrosion, (3) provides a uniform cooling medium, and one of various controls ...
Those RTs with power settings can vary transmission range from approximately 200 meters (660 feet) to 10 kilometers (km) (6.2 miles). Adding a power amplifier increases the line of sight (LOS) range to approximately 40 km (25 miles). (These ranges are for planning purposes only; terrain, weather, and antenna height can affect transmission range.)
The Eurofighter Typhoon combat aircraft with its nose fairing removed, revealing its Euroradar CAPTOR AESA radar antenna. An active electronically scanned array (AESA) is a type of phased-array antenna, which is a computer-controlled antenna array in which the beam of radio waves can be electronically steered to point in different directions without moving the antenna. [1]
A reconfigurable antenna is an antenna capable of modifying its frequency and radiation properties dynamically, in a controlled and reversible manner. [2] In order to provide a dynamic response, reconfigurable antennas integrate an inner mechanism (such as RF switches, varactors, mechanical actuators or tunable materials) that enable the intentional redistribution of the RF currents over the ...
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 ...
William Ittner Orr (1919–2001) was an engineer, educator, communicator, and ham radio operator. [1] [2] [3] He was the American author of numerous amateur radio and radio engineering texts.
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 ...