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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-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] |
Crosley Corporation
Powel Crosley Jr. (September 18, 1886 – March 28, 1961) was an American inventor, industrialist, and entrepreneur. He was also a pioneer in radio broadcasting, and owner of the Cincinnati Reds major league baseball team. In addition, Crosley's companies manufactured Crosley automobiles and radios, and operated WLW radio station. Crosley, once dubbed "The Henry Ford of Radio," was inducted into the Automotive Hall of Fame in 2010 and the National Radio Hall of Fame in 2013. He and his brother, Lewis M. Crosley, were responsible for many firsts in consumer products and broadcasting. During World War II, Crosley's facilities produced more proximity fuzes than any other U.S. manufacturer, and made several production design innovations. Crosley Field, a stadium in Cincinnati, Ohio, was renamed for him, and the street-level main entrance to Great American Ball Park in Cincinnati is named Crosley Terrace in his honor. Crosley's Pinecroft estate home in Cincinnati, Ohio, and Seagat ... [...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] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrator Supply
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] |
Korean War
, date = {{Ubl, 25 June 1950 – 27 July 1953 (''de facto'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950, month2=7, day2=27, year2=1953), 25 June 1950 – present (''de jure'')({{Age in years, months, weeks and days, month1=6, day1=25, year1=1950) , place = Korean Peninsula, Yellow Sea, Sea of Japan, Korea Strait, China–North Korea border , territory = Korean Demilitarized Zone established * North Korea gains the city of Kaesong, but loses a net total of {{Convert, 1506, sqmi, km2, abbr=on, order=flip, including the city of Sokcho, to South Korea. , result = Inconclusive , combatant1 = {{Flag, First Republic of Korea, name=South Korea, 1949, size=23px , combatant1a = {{Plainlist , * {{Flagicon, United Nations, size=23px United Nations Command, United Nations{{Refn , name = nbUNforces , group = lower-alpha , On 9 July 1951 troop constituents were: US: 70.4%, ROK: 23.3% other UNC: 6.3%{{Cite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revolutions Per Minute
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is a unit of rotational speed or rotational frequency for rotating machines. Standards ISO 80000-3:2019 defines a unit of rotation as the dimensionless unit equal to 1, which it refers to as a revolution, but does not define the revolution as a unit. It defines a unit of rotational frequency equal to s−1. The superseded standard ISO 80000-3:2006 did however state with reference to the unit name 'one', symbol '1', that "The special name revolution, symbol r, for this unit is widely used in specifications on rotating machines." The International System of Units (SI) does not recognize rpm as a unit, and defines the unit of frequency, Hz, as equal to s−1. :\begin 1~&\text &&=& 60~&\text \\ \frac~&\text &&=& 1~&\text \end A corresponding but distinct quantity for describing rotation is angular velocity, for which the SI unit is the ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horsepower
Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 watts. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses. It was later expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied among geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on 1 January 2010, the use of horsepower in the EU is permitted only as a supplementary unit. History The development of the stea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is equal to one event per second. The period is the interval of time between events, so the period is the reciprocal of the frequency. For example, if a heart beats at a frequency of 120 times a minute (2 hertz), the period, —the interval at which the beats repeat—is half a second (60 seconds divided by 120 beats). Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. Definitions and units For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term ''frequency'' is defined as the number of cycles or vibrations per unit of time. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Wave
A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration. It may refer to e.g. a laser or particle accelerator having a continuous output, as opposed to a pulsed output. Continuous wave is also the name given to an early method of radio transmission, in which a sinusoidal carrier wave is switched on and off. Information is carried in the varying duration of the on and off periods of the signal, for example by Morse code in early radio. In early wireless telegraphy radio transmission, CW waves were also known as "undamped waves", to distinguish this method from damped wave signals produced by earlier ''spark gap'' type transmitters. Radio Transmissions before CW Very early radio transmitters used a spark gap to produce radio-frequency oscillations in the transmitting antenna. The signals produced by these spark-gap transmitters c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the sidebands and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vintage Amateur Radio
Vintage amateur radio is a subset of amateur radio hobby where enthusiasts collect, restore, preserve, build, and operate amateur radio equipment from bygone years, such as those using vacuum tube technology. Popular modes of operation include speaking over amplitude modulation (AM), and communicating using Morse code through continuous wave (CW) radiotelegraphy. Some enthusiasts have interest in owning, restoring and operating vintage military and commercial radio equipment such as those from 1940s to 1960s. Some undertake to construct their own gear, known in ham slang as homebrewing, using vintage parts and designs. A number of amateur radio clubs and organizations sponsor contests, events, and swap meets that cater to this specialized aspect of the hobby. Appeal Vintage radio enthusiasts contend that the precise digital frequency displays and state-of-the-art, microprocessor-based features of modern amateur equipment lacks the aesthetic appeal and "soul" of amateur electroni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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