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SCR-694
The SCR-694 was a portable two way radio set used by the U.S. military during World War II. History The SCR-694 replaced the SCR-284 and was later replaced by the AN/GRC-9. Designed to provide communication between moving or stationary vehicles or as a portable field radio set, the SCR-694 was originally intended for use by mountain troops and airborne forces but soon became the Army-wide standard at battalion level. The SCR-694 saw use all over the army in many different theaters; notable instances include at regimental division headquarters during the Normandy invasion and the Cabanatuan prison raid as well as by scouts and reconnaissance units in the Pacific War. Specifications The SCR-694 "Radio set, Portable/Vehicular" consisted of the BC-1306 vacuum tube transmitter/receiver capable of AM and CW mode operation between 3.800 and 6.500 MHz. *Weight — 19.5 pounds. *Range — up to 15 miles on AM voice. Up to 30 miles reported on Morse code between moving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Corps Radio
Signal Corps Radios were U.S. Army military communications components that comprised "sets". Under the Army Nomenclature System, the abbreviation SCR initially designated "Set, Complete Radio", but was later misinterpreted as "Signal Corps Radio." Nomenclature The term SCR was part of a nomenclature system developed for the U.S. Signal Corps, used at least as far back as World War I. Three-letter designators beginning with "SC" were used to denote complete systems, while one and two-letter designators (such as "BC", for basic component, "FT" for mounting, etc.) were used for components. Only a few system designators were used: :::SCM Set, Complete, Meteorological :::SCR Set, Complete, Radio :::SCS Set, Complete, System SCR radio sets The U.S. Signal Corps used the term "sets" to denote specific groupings of individual components such as transmitters, receivers, power supplies, handsets, cases, and antennas. SCR radio sets ranged from the relatively small SCR-536 "handie t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCR-284
The SCR-284 was a World War II era combination transmitter and receiver used in vehicles or fixed ground stations. History The Crosley Corporation of Cincinnati, Ohio manufactured the Signal Corps Radio set SCR-284 that consisted of the BC-654 and associated support equipment. The SCR-284 was introduced in Africa during Operation Torch and was the first radio set used for communications from the beach to the U.S. Fleet to coordinate naval gunfire and beach radio networks.The American GI in Europe in World War II: The March to D-Day'. Stackpole Books; 22 September 2009. . p. 51–. The set was used by Merrill's Marauders while operating in the China-Burma-India Theater and missions behind Japanese lines in Burma to communicate with air transport and other military aircraft, although some radiomen complained that it was "very inefficient" compared to other radio sets and "very hard to generate power".Gavin Mortimer. Merrill's Marauders: The Untold Story of Unit Galahad and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCR-536
The SCR-536 was a hand-held radio transceiver used by the US Army Signal Corps in World War II. It is popularly referred to as a walkie talkie, although it was originally designated a "handie talkie". History The SCR-536 is often considered the first of modern hand-held, self-contained, "handie talkie" transceivers (two-way radios). It was developed in 1940 by a team led by Don Mitchell, chief engineer for Galvin Manufacturing (now Motorola Solutions) and was the first true hand-held unit to see widespread use. By July 1941, it was in mass production. In November 1942, the SCR-536 received coverage in the amateur radio magazine QST. It appeared on the cover as well as in Signal Corps advertising, and was featured as part of an article on the Signal Corps, “Smallest field unit of the Signal Corps”, in which a photo caption read: “it is not much larger or heavier than a conventional handset”. It was carried among the first waves to hit Omaha Beach at Normandy in June 1944 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCR-300
The SCR-300 was a portable radio transceiver used by US Signal Corps in World War II. This backpack-mounted unit was the first radio to be nicknamed a "walkie talkie". History In 1940, Motorola (then the Galvin Manufacturing Company) received a contract from the War Department to develop a portable, battery powered voice radio receiver/transmitter for field use by infantry units. The project engineering team consisted of Daniel E. Noble, who conceived of the design using frequency modulation, Henryk Magnuski who was the principal RF engineer, Marion Bond, Lloyd Morris, and Bill Vogel. The SCR-300 operated in the 40.0 to 48.0 MHz frequency range, and was channelized. Along with other mobile FM tank and artillery radios such as the SCR-508 (20.0 to 27.9 MHz) and the SCR-608 (27.0 to 38.9 MHz), the SCR-300 marked the beginning of the transition of combat-net radio from low-HF AM/CW to low- VHF FM. Although a relatively large backpack-carried radio rather than a handheld model, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Way Radio
A two-way radio is a radio that can both transmit and receive radio waves (a transceiver), unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and receiver in one unit, used for bidirectional person-to-person voice communication with other users with similar radios. Two-way radios are available in stationary ( base station), mobile (installed in vehicles), and hand-held portable models. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds. Two-way radios are used by groups of geographically separated people who need to keep in continuous voice communication, such as aircraft pilots and air traffic controllers, ship captains and harbormasters, emergency services personnel like firefighters, police officers, and ambulance paramedics, taxi and delivery services, soldiers and military units, fast food and warehouse employees, and radio amateurs. Two-way radio systems may use a single radio chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Radio Systems Of The United States
A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct military uniform. It may consist of one or more military branches such as an army, navy, air force, space force, marines, or coast guard. The main task of the military is usually defined as defence of the state and its interests against external armed threats. In broad usage, the terms ''armed forces'' and ''military'' are often treated as synonymous, although in technical usage a distinction is sometimes made in which a country's armed forces may include both its military and other paramilitary forces. There are various forms of irregular military forces, not belonging to a recognized state; though they share many attributes with regular military forces, they are less often referred to as simply ''military''. A nation's military may f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Transmitters
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] |
Vibrator (electronic)
A vibrator is an electromechanical device that takes a DC electrical supply and converts it into pulses that can be fed into a transformer. It is similar in purpose (although greatly different in operation) to the solid-state power inverter. Before the development of switch-mode power supplies and the introduction of semiconductor devices operating off low voltage, there was a requirement to generate voltages of about 50 to 250 V DC from a vehicle's battery. A vibrator was used to provide pulsating DC which could be converted to a higher voltage with a transformer, rectified, and filtered to create higher-voltage DC. It is essentially a relay using normally closed contacts to supply power to the relay coil, thus immediately breaking the connection, only to be reconnected very quickly through the normally closed contacts. It happens so rapidly it vibrates, and sounds like a buzzer. This same rapidly pulsing contact applies the rising and falling DC voltage to the transformer whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, second, s, and ampere, A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Oscillator
A crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is a quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators. However, other piezoelectricity materials including polycrystalline ceramics are used in similar circuits. A crystal oscillator relies on the slight change in shape of a quartz crystal under an electric field, a property known as inverse piezoelectricity. A voltage applied to the electrodes on the crystal causes it to change shape; when the voltage is removed, the crystal generates a small voltage as it elastically returns to its original shape. The quartz oscillates at a stable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morse Code
Morse code is a method used in telecommunication to encode 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 inventors of the telegraph. International Morse code encodes the 26 basic Latin letters through , one accented Latin letter (), the Arabic numerals, and a small set of punctuation and procedural signals ( 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 is the basic unit of time measurement in Morse code transmission. The duration of a ''dah'' is three times the duration of a ''dit''. Each ''dit'' or ''dah'' within an encoded character is followed by a period of signal absence, called a ''space'', equal to the ''dit'' duration. The letters of a word are separated by a space of duration equal to three ''dits'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (mass)
The pound or pound-mass is a unit of mass used in British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly , and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol is lbm (for most pound definitions), # ( chiefly in the U.S.), and or ″̶ (specifically for the apothecaries' pound). The unit is descended from the Roman (hence the abbreviation "lb"). The English word ''pound'' is cognate with, among others, German , Dutch , and Swedish . These units are historic and are no longer used (replaced by the metric system). Usage of the unqualified term ''pound'' reflects the historical conflation of mass and weight. This accounts for the modern distinguishing terms ''pound-mass'' and '' pound-force''. Etymology The word 'pound' and its cognates ultim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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