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Cage Antenna
A cage antenna (British cage aerial) is a radio antenna where a conventional design has been augmented by replacing a single long conductor with several parallel wires, connected at their ends, and held in position by ring spacers or support struts mounted on a central mast (if any). The "cage" is either mounted around a central mast (either conducting or non-conducting) or suspended from overhead wires. Examples A few examples of areal made of cage sections are: ; Quadrant antenna : A quadrant antenna is an omnidirectional shortwave transmitting antenna shaped like a rhombus or lozenge, made from two identical, opposing L-shaped cage dipoles lying in the same horizontal plane, aligned with their 'elbows' pointing in opposite directions ; Curtain antenna : A curtain array antenna is a directional shortwave transmitting antenna made of several parallel-aligned dipoles, each made of cage sections. History In 1921, an amateur radio operator An amateur radio operator is som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur T Cage Antenna 2BML 1922
An amateur () is generally considered a person who pursues an avocation independent from their source of income. Amateurs and their pursuits are also described as popular, informal, self-taught, user-generated, DIY, and hobbyist. History Historically, the amateur was considered to be the ideal balance between pure intent, open mind, and the interest or passion for a subject. That ideology spanned many different fields of interest. It may have its roots in the ancient Greek philosophy of amateur athletes competing in the Olympics. The ancient Greek citizens spent most of their time in other pursuits, but competed according to their natural talents and abilities. The "gentleman amateur" was a phenomenon among the gentry of Great Britain from the 17th century until the 20th century. With the start of the Age of Reason, with people thinking more about how the world works around them, (see science in the Age of Enlightenment), things like the cabinets of curiosities, and the wri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British English
British English is the set of Variety (linguistics), varieties of the English language native to the United Kingdom, especially Great Britain. More narrowly, it can refer specifically to the English language in England, or, more broadly, to the collective dialects of English throughout the United Kingdom taken as a single umbrella variety, for instance additionally incorporating Scottish English, Welsh English, and Northern Irish English. Tom McArthur (linguist), Tom McArthur in the Oxford English Dictionary, Oxford Guide to World English acknowledges that British English shares "all the ambiguities and tensions [with] the word 'British' and as a result can be used and interpreted in two ways, more broadly or more narrowly, within a range of blurring and ambiguity". Variations exist in formal (both written and spoken) English in the United Kingdom. For example, the adjective ''wee'' is almost exclusively used in parts of Scotland, north-east England, Northern Ireland, Ireland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Antenna
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment. An antenna is an array of conductor segments ( elements), electrically connected to the receiver or transmitter. Antennas can be designed to transmit and receive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhombus
In plane Euclidean geometry, a rhombus (: rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length. The rhombus is often called a "diamond", after the Diamonds (suit), diamonds suit in playing cards which resembles the projection of an Octahedron#Orthogonal projections, octahedral diamond, or a lozenge (shape), lozenge, though the former sometimes refers specifically to a rhombus with a 60° angle (which some authors call a calisson after calisson, the French sweet—also see Polyiamond), and the latter sometimes refers specifically to a rhombus with a 45° angle. Every rhombus is simple polygon, simple (non-self-intersecting), and is a special case of a parallelogram and a Kite (geometry), kite. A rhombus with right angles is a square. Etymology The word "rhombus" comes from , meaning something that spins, which derives from the verb , roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curtain Array
Curtain arrays are a class of large multielement directional radio transmitting wire antennas, used in the short-wave radio bands. They constitute a type of reflective array antenna, consisting of multiple wire dipole antennas, suspended in a vertical plane, often positioned in front of a "curtain" reflector made of a flat vertical screen of many long parallel wires. These are suspended by support wires strung between pairs of tall steel towers, reaching heights of up to high. Primarily employed for long-distance skywave (or ''skip'') transmission, they emit a beam of radio waves at a shallow angle into the sky just above the horizon, which is then reflected by the ionosphere back to Earth beyond the horizon. Curtain arrays are extensively used by international short-wave radio stations for broadcasting to large areas at transcontinental distances. Due to their powerful directional characteristics, curtain arrays are frequently utilized by government propaganda radio stations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Operator
An amateur radio operator is someone who uses equipment at an amateur radio station to engage in two-way personal communications with other amateur operators on radio frequencies assigned to the amateur radio service. Amateur radio operators have been granted an amateur radio license by a governmental regulatory authority after passing an examination on applicable regulations, electronics, radio theory, and radio operation. As a component of their license, amateur radio operators are assigned a call sign that they use to identify themselves during communication. About three million amateur radio operators are currently active worldwide. Amateur radio operators are also known as radio amateurs or hams. The term "ham" as a nickname for amateur radio operators originated in a pejorative usage (like "ham actor") by operators in commercial and professional radio communities, and dates to wired telegraphy. The word was subsequently adopted by amateur radio operators. Demographic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency Antenna Types
Radio is the technology of telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna (radio), antenna which radiates the waves. They can be received by other antennas connected to a radio receiver; this is the fundamental principle of radio communication. In addition to communication, radio is used for radar, radio navigation, radio control, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by Modulation, modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
