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Handheld Transceiver
A walkie-talkie, more formally known as a handheld transceiver (HT), is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald Hings, radio engineer Alfred J. Gross, Henryk Magnuski and engineering teams at Motorola. First used for infantry, similar designs were created for field artillery and tank units, and after the war, walkie-talkies spread to public safety and eventually commercial and jobsite work. Typical walkie-talkies resemble a telephone handset, with a speaker built into one end and a microphone in the other (in some devices the speaker also is used as the microphone) and an antenna mounted on the top of the unit. They are held up to the face to talk. A walkie-talkie is a half-duplex communication device. Multiple walkie-talkies use a single radio channel, and only one radio on the channel can transmit at a time, although any number can listen. The transceiver is normally in receive mode; w ... [...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] |
Raytheon
Raytheon Technologies Corporation is an American multinational aerospace and defense conglomerate headquartered in Arlington, Virginia. It is one of the largest aerospace and defense manufacturers in the world by revenue and market capitalization. In addition, it is one of the largest providers of intelligence services. Raytheon Technologies manufactures aircraft engines, avionics, aerostructures, cybersecurity, guided missiles, air defense systems, satellites, and drones. The company is also a large military contractor, getting a significant portion of its revenue from the U.S. government. The company is the result of the merger of equals between the aerospace subsidiaries of United Technologies Corporation (UTC) and the Raytheon Company, which was completed on April 3, 2020. Before the merger, UTC spun off its non-aerospace subsidiaries Otis Elevator Company and Carrier Corporation. UTC is the nominal survivor of the merger but it changed its name to Raytheon Technologies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AWM 017402 Noemfoor Radio
AWM may refer to: *Academies of West Memphis, a public high school in West Memphis, Arkansas * Appliance Wiring Material, covered by UL standard 758 *Apostolic Women's Ministries, an organization that serves the women of the Apostolic Church of Pentecost *Arctic Warfare Magnum or Accuracy International AWM, a British-made sniper rifle *Ardent Window Manager, an early window manager for the X Window System *Ashwell & Morden railway station, United Kingdom National Rail code AWM *Association for Women in Mathematics The Association for Women in Mathematics (AWM) is a professional society whose mission is to encourage women and girls to study and to have active careers in the mathematical sciences, and to promote equal opportunity for and the equal treatment o ..., a professional society to support women in mathematics *Atlantis World Media, parent company of the Atlantis Cable News (ACN) fictional news channel on the American TV series '' The Newsroom'' * Australian War Memorial, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Cell
upLine art drawing of a dry cell: 1. brass cap, 2. plastic seal, 3. expansion space, 4. porous cardboard, 5. zinc can, 6. carbon rod, 7. chemical mixture A dry cell is a type of electric battery, commonly used for portable electrical devices. Unlike wet cell batteries, which have a liquid electrolyte, dry cells use an electrolyte in the form of a paste, and are thus less susceptible to leakage. The dry cell was developed in 1886 by the German scientist Carl Gassner, after development of wet zinc–carbon batteries by Georges Leclanché in 1866. A type of dry cell was also developed by the Japanese Sakizō Yai in 1887. History left, upDry cell battery by Wilhelm Hellesen 1890 Many experimenters tried to immobilize the electrolyte of an electrochemical cell to make it more convenient to use. The Zamboni pile of 1812 is a high-voltage dry battery but capable of delivering only minute currents. Various experiments were made with cellulose, sawdust, spun glass, asbestos fiber ... [...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] |
Portable Radio SCR536
Portable may refer to: General * Portable building, a manufactured structure that is built off site and moved in upon completion of site and utility work * Portable classroom, a temporary building installed on the grounds of a school to provide additional classroom space where there is a shortage of capacity * Portable toilet, a modern, portable, self-contained outhouse manufactured of molded plastic Computing * Portable object (computing), a distributed computing term for an object which can be accessed through a normal method call while possibly residing in memory on another computer * Software portability, software that can easily be ported to multiple platforms * Portable applications, applications that do not require any kind of installation onto a computer, and can store data in the program's directory Electronics * Portable electronics * Portable device, a wearable or handheld device * Portable audio player, a personal electronic device that allows the user to listen to re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency Engineering
Radio-frequency (RF) engineering is a subset of electronic engineering involving the application of transmission line, Waveguide (electromagnetism), waveguide, Antenna (radio), antenna and Electromagnetic radiation, electromagnetic field principles to the design and application of devices that produce or use signals within the radio band, the frequency range of about 20 Hertz#SI multiples, kHz up to 300 Hertz#SI multiples, GHz. It is incorporated into almost everything that transmits or receives a radio wave, which includes, but is not limited to, mobile phones, radios, WiFi, and two-way radios. RF engineering is a highly specialized field that typically includes the following areas of expertise: # Design of antenna systems to provide radiative coverage of a specified geographical area by an electromagnetic field or to provide specified sensitivity to an electromagnetic field impinging on the antenna. # Design of coupling and transmission line structures to transport RF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation
Frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280.2C1.29 RLL, computing. In Analog signal, analog frequency modulation, such as radio broadcasting, of an audio signal representing voice or music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies may represent digits, such as '0' and '1'. FSK is widely used in computer modems, such as fax modems, telephone caller ID systems, garage door openers, and other low-frequency transmissions. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel E
Daniel is a masculine given name and a surname of Hebrew origin. It means "God is my judge"Hanks, Hardcastle and Hodges, ''Oxford Dictionary of First Names'', Oxford University Press, 2nd edition, , p. 68. (cf. Gabriel—"God is my strength"), and derives from two early biblical figures, primary among them Daniel from the Book of Daniel. It is a common given name for males, and is also used as a surname. It is also the basis for various derived given names and surnames. Background The name evolved into over 100 different spellings in countries around the world. Nicknames (Dan, Danny) are common in both English and Hebrew; "Dan" may also be a complete given name rather than a nickname. The name "Daniil" (Даниил) is common in Russia. Feminine versions (Danielle, Danièle, Daniela, Daniella, Dani, Danitza) are prevalent as well. It has been particularly well-used in Ireland. The Dutch names "Daan" and "Daniël" are also variations of Daniel. A related surname developed ... [...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] |
