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Radios
Radio is the technology of 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 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, 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 modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like air ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-way Radio
A two-way radio is a radio transceiver (a radio that can both transmit and receive radio waves), which is used for bidirectional person-to-person voice communication with other users with similar radios, in contrast to a broadcast receiver, which only receives transmissions. Two-way radios usually use a half-duplex communication channel, which permits two-way communication, albeit with the limitation that only one user can transmit at a time. (This is in contrast to simplex communication, in which transmission can only be sent in one direction, and full-duplex, which allows transmission in both directions simultaneously.) This requires users in a group to take turns talking. The radio is normally in receive mode so the user can hear all other transmissions on the channel. When the user wants to talk, they press a " push-to-talk" button, which turns off the receiver and turns on the transmitter; when the button is released, the receiver is activated again. Multiple channels are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Control
Radio control (often abbreviated to RC) is the use of control signals transmitted by radio to remotely operate a device. Examples of simple radio control systems are garage door openers and keyless entry systems for vehicles, in which a small handheld radio transmitter unlocks or opens doors. Radio control is also used for control of model vehicles from a hand-held radio transmitter. Industrial organization, Industrial, Military organization, military, and scientific research organizations make use of radio-controlled vehicles as well. A rapidly growing application is control of unmanned aerial vehicles (UAVs or drones) for both civilian and military uses, although these have more sophisticated control systems than traditional applications. History The idea of controlling unmanned vehicles (for the most part in an attempt to improve the accuracy of Torpedo, torpedoes for military purposes) predates the invention of radio. The latter half of the 1800s saw development of many suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KDKA (AM)
KDKA () is a list of North American broadcast station classes, class A, clear channel, AM radio station, licensed to Pittsburgh, Pennsylvania, owned and operated by Audacy, Inc. Its radio studios are located at the combined Audacy Pittsburgh facility in the Foster Plaza on Holiday Drive in Green Tree, and its transmitter site is at Allison Park. The station's programming is also carried over 93.7 KDKA-FM's HD Radio, HD2 digital subchannel, and is simulcast on FM translator W261AX at 100.1 MHz. KDKA features a news/talk radio format. Operating with a transmitter power of omnidirectional antenna, non-directional, the station can be heard during daylight hours throughout central and western Pennsylvania, along with portions of the adjacent states of Ohio, West Virginia, Maryland and New York State, plus the southernmost part of the Canadian province of Ontario. KDKA can be heard throughout the state of Pennsylvania and much of the Eastern United States and Eastern Canada at night. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Wave
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons. Electromagnetic radiation is produced by accelerating charged particles such as from the Sun and other celestial bodies or artificially generated for various applications. Its interaction with matter depends on wavelength, influencing its uses in communication, medicine, industry, and scientific research. Radio waves enable broadcasting and wireless communication, infrared is used in thermal imaging, visible light is essential for vision, and higher-energy radiation, such as X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Satellite Communication
A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently. The radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications satellites is to rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harding-Cox Presidential Election
United States presidential election, Presidential elections were held in the United States on November 2, 1920. The History of the Republican Party (United States), Republican ticket of senator Warren G. Harding of Ohio and governor Calvin Coolidge of Massachusetts defeated the History of the Democratic Party (United States), Democratic ticket of governor James M. Cox of Ohio and Assistant Secretary of the Navy, assistant secretary Franklin Roosevelt of New York. It was the first election held after the end of the First World War, and the first election after the ratification of the Nineteenth Amendment to the United States Constitution, Nineteenth Amendment gave nationwide suffrage to women. It was the first presidential election to have its results broadcast by radio. Incumbent president Woodrow Wilson, a Democrat who had served since 1913, privately hoped for a third term despite severe physical and mental disabilities from a stroke, but he had very little support. Former p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Electrical And Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office in New York City and an operations center in Piscataway, New Jersey. The IEEE was formed in 1963 as an amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. History The IEEE traces its founding to 1884 and the American Institute of Electrical Engineers. In 1912, the rival Institute of Radio Engineers was formed. Although the AIEE was initially larger, the IRE attracted more students and was larger by the mid-1950s. The AIEE and IRE merged in 1963. The IEEE is headquartered in New York City, but most business is done at the IEEE Operations Center in Piscataway, New Jersey, opened in 1975. The Australian Section of the IEEE existed between 1972 and 1985, after which it split into state- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elon University
Elon University is a private university in Elon, North Carolina, United States. Founded in 1889 as Elon College, the university is organized into six schools, most of which offer bachelor's degrees and several of which offer master's degrees or professional doctorate degrees. Located in North Carolina's Piedmont region, Elon is situated on a suburban campus between the cities of Greensboro, North Carolina, Greensboro and Raleigh, North Carolina, Raleigh. Elon's athletic teams compete in NCAA Division I as members of the Coastal Athletic Association. History Elon College was founded by the Christian Connection, which later became a part of the United Church of Christ. The charter for Elon College was issued by the North Carolina legislature in 1889. William S. Long was the first president and the original student body consisted of 76 students. In 1923, a fire destroyed most of the campus, including school records, classrooms, the library, and the chapel. The board of trustees v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a telecommunications method which Character encoding, encodes Written language, text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of the early developers of the system adopted for electrical telegraphy. International Morse code encodes the 26 ISO basic Latin alphabet, basic Latin letters to , one Diacritic, accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals (Prosigns for Morse code, prosigns). There is no distinction between upper and lower case letters. Each Morse code symbol is formed by a sequence of ''dits'' and ''dahs''. The ''dit'' duration can vary for signal clarity and operator skill, but for any one message, once the rhythm is established, a beat (music), half-beat is the basic unit of time measurement in Morse code. The duration of a ''dah'' is three times the duration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guglielmo Marconi
Guglielmo Giovanni Maria Marconi, 1st Marquess of Marconi ( ; ; 25 April 1874 – 20 July 1937) was an Italian electrical engineer, inventor, and politician known for his creation of a practical radio wave-based Wireless telegraphy, wireless telegraph system. This led to Marconi being credited as the inventor of radio and sharing the 1909 Nobel Prize in Physics with Karl Ferdinand Braun "in recognition of their contributions to the development of wireless telegraphy". His work laid the foundation for the development of radio, television, and all modern wireless communication systems. Marconi was also an entrepreneur and businessman who founded the Wireless Telegraph & Signal Company (which became the Marconi Company) in the United Kingdom of Great Britain and Ireland, United Kingdom in 1897. In 1929, Marconi was ennobled as a marchese, marquess (''marchese'') by Victor Emmanuel III. In 1931, he set up Vatican Radio for Pope Pius XI. Biography Early years Guglielmo Giovanni Mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Hertz
Heinrich Rudolf Hertz (; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's equations of electromagnetism. Biography Heinrich Rudolf Hertz was born in 1857 in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic family. His father was Gustav Ferdinand Hertz. His mother was Anna Elisabeth Pfefferkorn. While studying at the Gelehrtenschule des Johanneums in Hamburg, Hertz showed an aptitude for sciences as well as languages, learning Arabic. He studied sciences and engineering in the German cities of Dresden, Munich and Berlin, where he studied under Gustav R. Kirchhoff and Hermann von Helmholtz. In 1880, Hertz obtained his PhD from the University of Berlin, and for the next three years remained for post-doctoral study under Helmholtz, serving as his assistant. In 1883, Hertz took a post as a lecturer in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyless Entry System
A remote keyless system (RKS), also known as remote keyless entry (RKE) or remote central locking, is an electronic lock that controls access to a building or vehicle by using an electronic remote control (activated by a handheld device or automatically by proximity). RKS largely and quickly superseded ''keyless entry'', a budding technology that restrictively bound locking and unlocking functions to vehicle-mounted keypads. Widely used in automobiles, an RKS performs the functions of a standard car key without physical contact. When within a few yards of the car, pressing a button on the remote can lock or unlock the doors, and may perform other functions. A remote keyless system can include both ''remote keyless entry'' (RKE), which unlocks the doors, and '' remote keyless ignition'' (RKI), which starts the engine. Numerous manufacturers have offered entry systems that use door- or pillar-mounted keypad entry systems; touchless passive entry / smart key systems that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
