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75A-4 And KWS-1
The 74A4 and KWS-1 is an amateur radio receiver and transmitter pair made by the Collins Radio Company of Cedar Rapids, Iowa that were introduced in 1955. They were designed to operate using the then new single-sideband (SSB) voice modulation as well as CW and AM modes. They were influential in popularizing SSB. Debut The KWS-1 transmitter along with the 75A-4 receiver, together, cost over $2500 when new (equivalent to over $20,000 in 2012 dollars). Collins products at the time were considered 'top of the line'. Ham radio enthusiasts nicknamed the pair the "Gold Dust Twins", since they were unaffordable for most amateur radio enthusiasts when first introduced. Both radios used vacuum tubes and employed Collins innovations including mechanical filters and permeability tuned oscillators. The KWS-1 final amplifier use a pair of 4X150 power tubes and operated at a power input of one kilowatt, the maximum allowed under Federal Communications Commission The Federal Communications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collins 75A-4 Peoria
Collins may refer to: People Surname Given name * Collins O. Bright (1917–?), Sierra Leonean diplomat * Collins Chabane (1960–2015), South African Minister of Public Service and Administration * Collins Cheboi (born 1987), Kenyan middle-distance runner * Collins Denny (1854–1943), American Bishop of the Methodist Episcopal Church, South * Collins Denny Jr. (1899–1964), American pro-segregationist lawyer. * Collins Hagler (born 1935), Canadian football player * Collins Injera (born 1986), Kenyan rugby player * Collins H. Johnston (1859–1936), American football player, medical doctor, surgeon, and civic leader * Collins John (born 1985), Liberia-born Dutch footballer * Collins Mbesuma (born 1984), Zambian footballer nicknamed ''The Hurricane'' or ''Ntofontofo'' * Collins Mensah (born 1961), Ghanaian sprinter * Collins Nweke (born 1965), Belgian politician of the Green Party * Collins Obuya (born 1981), Kenyan cricketer Companies * Collins Aerospace, avionics manufactur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio
Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications. The term "amateur" is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;" (either direct monetary or other similar reward) and to differentiate it from commercial broadcasting, public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and '' amateur-satellite service'') is established by the International Telecommunication Union (ITU) through the Radio Regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station licenses with a unique identifying call sign, which mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collins Radio Company
Rockwell Collins was a multinational corporation headquartered in Cedar Rapids, Iowa, providing avionics and information technology systems and services to government agencies and aircraft manufacturers. It was formed when the Collins Radio Company, facing financial difficulties, was purchased by Rockwell International in 1973. In 2001, the avionics division of Rockwell International was spun off to form the current Rockwell Collins, Inc, retaining its name. The company was acquired by United Technologies Corporation on November 27, 2018, and now operates as part of Collins Aerospace, a subsidiary of Raytheon Technologies. History Arthur A. Collins founded Collins Radio Company in 1933 in Cedar Rapids, Iowa. It designed and produced both shortwave radio equipment and equipment for the burgeoning AM radio broadcast industry. Collins was solicited by the military, the scientific community, and the larger AM radio stations for special equipment. Collins supplied the equipment t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cedar Rapids, Iowa
Cedar Rapids () is the second-largest city in Iowa, United States and is the county seat of Linn County, Iowa, Linn County. The city lies on both banks of the Cedar River (Iowa River), Cedar River, north of Iowa City, Iowa, Iowa City and northeast of Des Moines, Iowa, Des Moines, the state's capital and largest city. It is a part of the Cedar Rapids/Iowa City region of Eastern Iowa, which includes Linn County, Iowa, Linn, Benton County, Iowa, Benton, Cedar County, Iowa, Cedar, Iowa County, Iowa, Iowa, Jones County, Iowa, Jones, Johnson County, Iowa, Johnson, and Washington County, Iowa, Washington counties. As of the 2020 United States Census, the city population was 137,710. The estimated population of the three-county Cedar Rapids metropolitan area, Metropolitan Statistical Area, which includes the nearby cities of Marion, Iowa, Marion and Hiawatha, Iowa, Hiawatha, was 255,452 in 2008. Cedar Rapids is an economic hub of the state, located at the core of the Interstate 380 (Io ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-sideband Modulation
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a linear ampl ... [...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] |
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] |
Gold Dust Twins
The Gold Dust Twins, the trademark for Fairbank's Gold Dust washing powder products, appeared in printed media as early as 1892. "Goldie" and "Dusty", the original Gold Dust Twins, were often shown doing household chores together. In general use since the early 1900s, the term has had popular use as a nickname on several occasions. The sobriquet, "Gold Dust Twins," is often used to describe two talented individuals working closely together for a common goal, especially in sports. Background Gold Dust washing powder was an all-purpose cleaning agent first introduced in the late 1880s by the Nathaniel Kellogg Fairbank Soap Company based in New York City. Gold Dust was distributed in America by the Lever Brothers Company of Cambridge, Massachusetts. Its first regional success was in the midwestern United States. Gold Dust Washing Powders had been marketed nationally since the mid-1890s, becoming the top-selling national brand of washing powder by 1903. Gold Dust products were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum Tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. The type known as a thermionic tube or thermionic valve utilizes thermionic emission of electrons from a hot cathode for fundamental electronic functions such as signal amplifier, amplification and current rectifier, rectification. Non-thermionic types such as a vacuum phototube, however, achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light intensities. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode (i.e. Fleming valve), invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through the device—fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Filter
A mechanical filter is a signal processing filter usually used in place of an electronic filter at radio frequencies. Its purpose is the same as that of a normal electronic filter: to pass a range of signal frequencies, but to block others. The filter acts on mechanical vibrations which are the analogue of the electrical signal. At the input and output of the filter, transducers convert the electrical signal into, and then back from, these mechanical vibrations. The components of a mechanical filter are all directly analogous to the various elements found in electrical circuits. The mechanical elements obey mathematical functions which are identical to their corresponding electrical elements. This makes it possible to apply electrical network analysis and filter design methods to mechanical filters. Electrical theory has developed a large library of mathematical forms that produce useful filter frequency responses and the mechanical filter designer is able to make direct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Screw
A leadscrew (or lead screw), also known as a power screw or translation screw,Bhandari, p. 202. is a screw used as a linkage in a machine, to translate turning motion into linear motion. Because of the large area of sliding contact between their male and female members, screw threads have larger frictional energy losses compared to other linkages. They are not typically used to carry high power, but more for intermittent use in low power actuator and positioner mechanisms. Leadscrews are commonly used in linear actuators, machine slides (such as in machine tools), vises, presses, and jacks.Shigley, p. 400. Leadscrews are a common component in electric linear actuators. Leadscrews are manufactured in the same way as other thread forms (they may be rolled, cut, or ground). A lead screw is sometimes used with a split nut (also called half nut) which allows the nut to be disengaged from the threads and moved axially, independently of the screw's rotation, when needed ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Communications Commission
The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdiction over the areas of broadband access, fair competition, radio frequency use, media responsibility, public safety, and homeland security. The FCC was formed by the Communications Act of 1934 to replace the radio regulation functions of the Federal Radio Commission. The FCC took over wire communication regulation from the Interstate Commerce Commission. The FCC's mandated jurisdiction covers the 50 states, the District of Columbia, and the territories of the United States. The FCC also provides varied degrees of cooperation, oversight, and leadership for similar communications bodies in other countries of North America. The FCC is funded entirely by regulatory fees. It has an estimated fiscal-2022 budget of US $388 million. It has 1,482 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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