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Radio
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 ob ... [...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] |
Radio Wave
Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths greater than , about the diameter of a grain of rice. Radio waves with frequencies above about 1 GHz and wavelengths shorter than 30 centimeters are called microwaves. Like all electromagnetic waves, radio waves in vacuum travel at the speed of light, and in the Earth's atmosphere at a slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical radio source, astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna (radio), antenna, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Navigation
Radio navigation or radionavigation is the application of radio waves to geolocalization, determine a position of an object on the Earth, either the vessel or an obstruction. Like radiolocation, it is a type of Radiodetermination-satellite service, radiodetermination. The basic principles are measurements from/to electric beacons, especially * Direction (geometry), Angular directions, e.g. by bearing, radio phases or interferometry, * Distance measuring equipment, Distances, e.g. ranging by measurement of time of flight between one transmitter and multiple receivers or vice versa, * Distance ''differences'' by measurement of multilateration, times of arrival of signals from one transmitter to multiple receivers or vice versa * Partly also velocity, e.g. by means of radio Doppler shift. Combinations of these measurement principles also are important—e.g., many radars measure range and azimuth of a target. Bearing-measurement systems These systems used some form of directional ... [...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] |
Radio Receiver
In radio communications, a radio receiver, also known as a receiver, a wireless, or simply a radio, is an electronic device that receives radio waves and converts the information carried by them to a usable form. It is used with an antenna. The antenna intercepts radio waves (electromagnetic waves of radio frequency) and converts them to tiny alternating currents which are applied to the receiver, and the receiver extracts the desired information. The receiver uses electronic filters to separate the desired radio frequency signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation. Radio receivers are essential components of all systems based on radio technology. The information produced by the receiver may be in the form of sound, video (television), or digital data. A radio receiver may be a separate piece of electronic equ ... [...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] |
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] |
Telecommunication
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of transmission may be divided into communication channels for multiplexing, allowing for a single medium to transmit several concurrent Session (computer science), communication sessions. Long-distance technologies invented during the 20th and 21st centuries generally use electric power, and include the electrical telegraph, telegraph, telephone, television, and radio. Early telecommunication networks used metal wires as the medium for transmitting signals. These networks were used for telegraphy and telephony for many decades. In the first decade of the 20th century, a revolution in wireless communication began with breakthroughs including those made in radio communications by Guglielmo Marconi, who won the 1909 Nobel Prize in Physics. Othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating current, alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves Radio propagation, propagating through space and electric currents moving in metal Electrical conductor, conductors, used with a transmitter or receiver (radio), receiver. In transmission (telecommunications), transmission, a radio transmitter supplies an electric current to the antenna's Terminal (electronics), terminals, and the antenna radiates the energy from the current as electromagnetic radiation, electromagnetic waves (radio waves). In receiver (radio), 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 amplifier, amplified. Antennas are essential components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
