|
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. 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 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 considerable effort countering it. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated between the Baltic and North seas to the north, and the Alps to the south; it covers an area of , with a population of almost 84 million within its 16 constituent states. Germany 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 nation's capital and most populous city is Berlin and its financial centre is Frankfurt; the largest urban area is the Ruhr. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity. A region named Germania was documented before AD 100. In 962, the Kingdom of Germany formed the bulk of the Holy Roman Empire. During the 16th ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Hollmann
Hans Erich (Eric) Hollmann (4 November 1899 – 19 November 1960) was a German electronic specialist who made several breakthroughs in the development of radar. Hollmann was born in Solingen, Germany. He became interested in radio and even as a teenager subscribed to the technical magazines of the day. Late in World War I he became a prisoner of war of the French and did not return to Germany until 1920. He then studied at the Technical University at Darmstadt until he received his doctorate in 1928. Hollmann's doctoral research included the development of an ultra-short-wave transmitter and receiver for centimetre and decimetre waves. This gained the attention of ''Telefunken'', and ultimately led to their development of the first microwave telecommunication system. In 1930 Hollmann moved to the Heinrich-Hertz Institute for Oscillatory Research in Berlin. There he continued studies in microwaves and cathode ray tubes and also worked on the ionosphere research and radio astr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bundesarchiv Bild 101I-662-6660-27A, Frankreich, Radargerät "Würzburg"
, type = Archive , seal = , seal_size = , seal_caption = , seal_alt = , logo = Bundesarchiv-Logo.svg , logo_size = , logo_caption = , logo_alt = , image = Bundesarchiv Koblenz.jpg , image_caption = The Federal Archives in Koblenz , image_alt = , formed = , preceding1 = , preceding2 = , dissolved = , superseding1 = , superseding2 = , agency_type = , jurisdiction = , status = Active , headquarters = PotsdamerStraße156075Koblenz , coordinates = , motto = , employees = , budget = million () , chief1_name = Michael Hollmann , chief1_position = President of the Federal Archives , chief2_name = Dr. Andrea Hänger , chief2_position ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraboloid
In geometry, a paraboloid is a quadric surface that has exactly one axis of symmetry and no center of symmetry. The term "paraboloid" is derived from parabola, which refers to a conic section that has a similar property of symmetry. Every plane section of a paraboloid by a plane parallel to the axis of symmetry is a parabola. The paraboloid is hyperbolic if every other plane section is either a hyperbola, or two crossing lines (in the case of a section by a tangent plane). The paraboloid is elliptic if every other nonempty plane section is either an ellipse, or a single point (in the case of a section by a tangent plane). A paraboloid is either elliptic or hyperbolic. Equivalently, a paraboloid may be defined as a quadric surface that is not a cylinder, and has an implicit equation whose part of degree two may be factored over the complex numbers into two different linear factors. The paraboloid is hyperbolic if the factors are real; elliptic if the factors are complex conjugate ... [...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 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 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 hear the reflections of that signal off distant targets. Since the radio signal has to travel out to the target and back ag ... [...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 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 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 can be coupled back into the input cavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hitler
Adolf Hitler (; 20 April 188930 April 1945) was an Austrian-born German politician who was dictator of Germany from 1933 until his death in 1945. He rose to power as the leader of the Nazi Party, becoming the chancellor in 1933 and then taking the title of in 1934. During his dictatorship, he initiated World War II in Europe by invading Poland on 1 September 1939. He was closely involved in military operations throughout the war and was central to the perpetration of the Holocaust: the genocide of about six million Jews and millions of other victims. Hitler was born in Braunau am Inn in Austria-Hungary and was raised near Linz. He lived in Vienna later in the first decade of the 1900s and moved to Germany in 1913. He was decorated during his service in the German Army in World War I. In 1919, he joined the German Workers' Party (DAP), the precursor of the Nazi Party, and was appointed leader of the Nazi Party in 1921. In 1923, he attempted to seize governmental ... [...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. Development of the Ju 52 commenced during 1930, headed by German Aerospace engineering, aeronautical engineer Ernst Zindel. The aircraft's design incorporated a wikt:corrugated, corrugated duralumin metal skin as a strengthening measure, which was very unusual at the time. The Ju 52's maiden flight was performed on 13 October 1930. It was initially designed with a single engine, however, it was produced in quantity as a trimotor. The primary early production model, the ''Ju 52/3m'', was principally operated as a 17-seat airliner or utility transport aircraft by various civil operators during the 1930s. Following the rise of Nazi Germany, thousands of Ju 52s were procured as a staple military transport of the nation. The ''Ju 52/3mg7e'' was the principal production model. The Ju 52 was in production between 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seetakt Radar
Seetakt was a shipborne radar developed in the 1930s and used by Nazi Germany's ''Kriegsmarine'' during World War II. Development In Germany during the late 1920s, Hans Hollmann began working in the field of microwaves, which were to later become the basis of 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 on radar-like systems. In 1928 Hollmann, von Willisen and Paul-Günther Erbslöh started a company Gesellschaft für elektroakustische und mechanische Apparate (GEMA). In the autumn of 1934, GEMA built the first commercial radar system for detecting ships, similar to a system developed by Christian Hülsmeyer. Operating in the 50 cm range it could detect ships up to 10 km away. This early version of the system only provided a warning ... [...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 (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel universes, extraterrestrial life, sentient artificial intelligence, cybernetics, certain forms of immortality (like mind uploading), and the singularity. Science fiction predicted several existing inventions, such as the atomic bomb, robots, and borazon, whose names entirely match their fictional predecessors. In addition, science fiction might serve as an outlet to facilitate future scientific and technological innovations. Science fiction can trace its roots to ancient mythology. It is also related to fantasy, horror, and superhero fiction and contains many subgenres. Its exact definition has long been disputed among authors, critics, scholars, and readers. Science fiction, in literature, film, television, and other media, has beco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
