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Würzburg Radar
The low-UHF band Würzburg radar was the primary ground-based tracking radar for the Wehrmacht's Luftwaffe and Kriegsmarine (German Navy) during World War II. Initial development took place before the war and the apparatus entered service in 1940. Eventually, over 4,000 Würzburgs of various models were produced. It took its name from the city of Würzburg in Bavaria. There were two primary models of the system. The first Würzburg was a transportable model that could be folded for transit and then brought into operation quickly after emplacement and levelling. The A models began entering service in May 1940 and saw several updated versions over the next year to improve accuracy, notably the addition of conical scanning in the D model of 1941. The larger Würzburg-''Riese'' (giant) was based on the D model but used a much larger parabolic reflector to further improve resolution at the cost of no longer being mobile. As one of German's primary radars, the British spent considera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total population of over 84 million in an area of , making it the most populous member state of the European Union. It borders Denmark to the north, Poland and the Czech Republic to the east, Austria and Switzerland to the south, and France, Luxembourg, Belgium, and the Netherlands to the west. The Capital of Germany, nation's capital and List of cities in Germany by population, most populous city is Berlin and its main financial centre is Frankfurt; the largest urban area is the Ruhr. Settlement in the territory of modern Germany began in the Lower Paleolithic, with various tribes inhabiting it from the Neolithic onward, chiefly the Celts. Various Germanic peoples, Germanic tribes have inhabited the northern parts of modern Germany since classical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telefunken
Telefunken was a German radio and television producer, founded in Berlin in 1903 as a joint venture between Siemens & Halske and the ''AEG (German company), Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ("General electricity company"). Prior to World War I, the company set up the first world-wide network of communications and was the first in the world to sell electronic televisions with cathode-ray tubes, in Germany in 1934. The brand had several incarnations: * ''Gesellschaft für drahtlose Telegraphie Gesellschaft mit beschränkter Haftung, m.b.H., System Telefunken'', founded in 1903 as a joint venture between AEG and Siemens & Halske * ''Telefunken, Gesellschaft für drahtlose Telegraphie m.b.H.'', in 1923; since 1941 as subsidiary of AEG alone * ''Telefunken Gesellschaft mit beschränkter Haftung, GmbH'', in 1955 * ''Telefunken Aktiengesellschaft (AG)'', in 1963 * ''Allgemeine Elektrizitäts-Gesellschaft AEG-Telefunken'', created in 1967 through a merger between Telefunken ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulse-repetition Frequency
The pulse-repetition frequency (PRF) is the number of pulses of a repeating signal in a specific time unit. The term is used within a number of technical disciplines, notably radar. In radar, a radio signal of a particular carrier frequency is turned on and off; the term "frequency" refers to the carrier, while the PRF refers to the number of switches. Both are measured in terms of cycle per second, or hertz. The PRF is normally much lower than the frequency. For instance, a typical World War II radar like the Type 7 AMES Type 7, GCI radar had a basic carrier frequency of 209 MHz (209 million cycles per second) and a PRF of 300 or 500 pulses per second. A related measure is the Radar signal characteristics#pulse width, pulse width, the amount of time the transmitter is turned on during each pulse. After producing a brief pulse of radio signal, the transmitter is turned off in order for the receiver units to detect the reflections of that signal off distant targets. Since the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klystron
A klystron is a specialized linear-beam vacuum tube, invented in 1937 by American electrical engineers Russell and Sigurd Varian,Pond, Norman H. "The Tube Guys". Russ Cochran, 2008 p.31-40 which is used as an amplifier for high radio frequencies, from ultra high frequency, UHF up into the microwave range. Low-power klystrons are used as oscillators in terrestrial microwave relay communications links, while high-power klystrons are used as output tubes in UHF television transmitters, satellite communication, radar transmitters, and to generate the drive power for modern particle accelerators. In a klystron, an electron beam interacts with radio waves as it passes through cavity resonator, resonant cavities, metal boxes along the length of a tube. The electron beam first passes through a cavity to which the input signal is applied. The energy of the electron beam amplifies the signal, and the amplified signal is taken from a cavity at the other end of the tube. The output signal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hitler
Adolf Hitler (20 April 1889 – 30 April 1945) was an Austrian-born German politician who was the dictator of Nazi Germany from 1933 until Death of Adolf Hitler, his suicide in 1945. Adolf Hitler's rise to power, He rose to power as the leader of the Nazi Party, becoming Chancellor of Germany#Nazi Germany (1933–1945), the chancellor in 1933 and then taking the title of in 1934. His invasion of Poland on 1 September 1939 marked the start of the Second World War. He was closely involved in military operations throughout the war and was central to the perpetration of the Holocaust: the genocide of Holocaust victims, about six million Jews and millions of other victims. Hitler was born in Braunau am Inn in Austria-Hungary and moved to German Empire, Germany in 1913. He was decorated during his service in the German Army in the First World War, receiving the Iron Cross. In 1919 he joined the German Workers' Party (DAP), the precursor of the Nazi Party, and in 1921 was app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Junkers Ju 52
The Junkers Ju 52/3m (nicknamed ''Tante Ju'' ("Aunt Ju") and ''Iron Annie'') is a transport aircraft that was designed and manufactured by German aviation company Junkers. First introduced during 1930 as a civilian airliner, it was adapted into a military transport aircraft by Germany's Nazi regime, who exercised power over the company for its war efforts, over the objections of the company's founder Hugo Junkers. Development of the Ju 52 commenced in the late 1920s, headed by German aeronautical engineer Ernst Zindel. The aircraft's design incorporated a corrugated duralumin metal skin as a strengthening measure, which was a material design pioneered by Junkers and used on many of their aircraft, including the popular Junkers F 13 1920s, the record-setting Junkers W 33, and Junkers W34. The corrugation was both a strength and a weakness; it provided increased structural strength but also increased aerodynamic drag. But more importantly it allowed the practical use of alum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seetakt Radar
Seetakt was a shipborne radar developed in the 1930s and used by the German Navy (''Kriegsmarine'') during World War II. It is the first naval radar to enter service, and among the earliest radars of any sort. It provided range measurements with an accuracy on the order of , more than enough for gunnery. Its angle accuracy was not very good, but the development of lobe switching specifically for this radar provided about 1 degree accuracy, not enough to directly lay the guns, but still useful for initial plotting and aiding the optical spotters find their target. Development In Germany during the late 1920s, Hans Hollmann began working in the field of microwave frequencies, which later were used by almost all radar systems. In 1935 he published ''Physics and Technique of Ultrashort Waves'', which was picked up by researchers around the world. At the time he had been most interested in their use for communications, but he and his partner Hans-Karl von Willisen had also worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freya Radar
Freya was an early warning radar deployed by Germany during World War II; it was named after the Norse goddess Freyja. During the war, over a thousand stations were built. A naval version operating on a slightly different wavelength was also developed as the ''Seetakt''. Development First tests of what would become the "''Freya''" were conducted in early 1937, with initial delivery of an operational radar to the ''Kriegsmarine'' in 1938 by the GEMA company. Freya supported an early version of Identification friend or foe (IFF). Aircraft equipped with the FuG 25a "''Erstling''" IFF system could be successfully queried across ranges of over 100 km. The "AN" version gained a switchable phasing line for the antenna. Switching in the phasing line led to a phase displacement of the antenna's radiation pattern and with that, a squinting to the left or right. This enabled the system in effect to switch from the rather broad "scanning for maxima" to narrow lobe switching ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Fiction
Science fiction (often shortened to sci-fi or abbreviated SF) is a genre of speculative fiction that deals with imaginative and futuristic concepts. These concepts may include information technology and robotics, biological manipulations, space exploration, time travel, Parallel universes in fiction, parallel universes, and extraterrestrials in fiction, extraterrestrial life. The genre often explores human responses to the consequences of projected or imagined scientific advances. Science fiction is related to fantasy (together abbreviated wikt:SF&F, SF&F), Horror fiction, horror, and superhero fiction, and it contains many #Subgenres, subgenres. The genre's precise Definitions of science fiction, definition has long been disputed among authors, critics, scholars, and readers. Major subgenres include hard science fiction, ''hard'' science fiction, which emphasizes scientific accuracy, and soft science fiction, ''soft'' science fiction, which focuses on social sciences. Other no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Runge
Wilhelm Tolmé Runge (June 10, 1895 – June 9, 1987) was a German electrical engineer and physicist who had a major involvement in developing radar systems in Germany. Early life Wilhelm Runge was born and raised in Hanover, where his father, Carl Runge, was a well-known professor of mathematics at the Technische Hochschule Hannover (now remembered chiefly as the co-eponym of the Runge–Kutta method). Military service When World War I started in 1914, Runge was not doing well in his engineering studies. In 1915 he volunteered to join the German Army. Unsuccessful in officer training, he was sent to the Western Front and the infamous trench warfare. By early 1917 he had reached the rank of Sergeant and was rescued from likely death by being selected by Lieutenant Richard Courant – a mathematician friend of his father who later married his sister, Nina – to go to German-occupied northern France and assist in developing the (), a seismic apparatus. Education At the close ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Warning Radar
An early-warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as ''early'' as possible before the intruder reaches its target, giving the air defences the maximum time in which to operate. This contrasts with systems used primarily for tracking or gun laying, which tend to offer shorter ranges but offer much higher accuracy. EW radars tend to share a number of design features that improve their performance in the role. For instance, EW radar typically operates at lower frequencies, and thus longer wavelengths, than other types. This greatly reduces their interaction with rain and snow in the air, and therefore improves their performance in the long-range role where their coverage area will often include precipitation. This also has the side-effect of lowering their optical resolution, but this is not important in this role. Likewise, EW radars often use much lower pulse repetition frequency to maximiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
