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Antennas can be classified in various ways, and various writers organize the different aspects of antennas with different priorities, depending on whether their text is most focused on specific frequency bands; or antenna size, construction, and placement feasibility; or explicating principles of radio theory and engineering that underlie, guide, and constrain antenna design.
A quadrant antenna is a 'V' antenna with an unusual overall length of a full wavelength, with two half-wave horizontal elements meeting at a right angle where it is fed. [14] Quadrant antennas produce mostly horizontal polarization at low to intermediate elevation angles and have nearly omnidirectional radiation patterns. [15]
For this, a new quadrant-antenna was installed for transmissions to Europe. Quadrant-Antenna (omnidirectional for 6 and 7 MHz) to serve central Europe. In the background are the main towers of the Wertachtal shortwave transmitter site. Other broadcasters using the site included Adventist World Radio from 1996, et Family Radio from 2001.
Antenna (radio) In radio engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves, or radio waves into an electric current. [1][2] It is the interface between radio waves propagating through space and electric currents moving in metal conductors ...
Monopulse radar is a radar system that uses additional encoding of the radio signal to provide accurate directional information. The name refers to its ability to extract range and direction from a single signal pulse. Monopulse radar avoids problems seen in conical scanning radar systems, which can be confused by rapid changes in signal strength.
The AN/ALR-67 countermeasures warning and control system is the standard threat warning system for tactical aircraft and was specifically designed for the A-6E/SWIP, AV-8B, F-14B, F-14D and F/A-18. The system detects, identifies and displays radars and radar-guided weapon systems in the C to J frequency range (about 0.5 to 20 GHz).
Horn antenna. Pyramidal microwave horn antenna, with a bandwidth of 0.8 to 18 GHz. A coaxial cable feedline attaches to the connector visible at top. This type is called a ridged horn; the curving fins visible inside the mouth of the horn increase the antenna's bandwidth. The first modern horn antenna in 1938 with inventor Wilmer L. Barrow.
Bearing (navigation) A standard Brunton compass, used commonly by geologists and surveyors to obtain a bearing in the field. In navigation, bearing or azimuth is the horizontal angle between the direction of an object and north or another object. The angle value can be specified in various angular units, such as degrees, mils, or grad.