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Wacław Struszyński
Wacław Struszyński (; 1904–1980) was a Polish electronics engineer who made a vital contribution to the defeat of U-boats in the Battle of the Atlantic. He designed an exceptional radio antenna which enabled effective high frequency (HF) radio direction finding systems to be installed on Royal Navy convoy escort ships. Such direction finding systems were referred to as HF/DF or Huff-Duff, and enabled the bearings of U-boats to be determined when the U-boats made high frequency radio transmissions. Early life Struszynski was born in Wieruszów near Łódź (now in Poland) in 1904. He spent his youth in Moscow, but the family returned to Poland in 1918. He received his master's degree in Engineering (''Dipl. Ing.'') at the Warsaw University of Technology in 1929, and joined the Polish State Telecommunication Establishment, where he became head of the Direction Finding Division. When Poland was invaded in 1939, he was evacuated from Warsaw, and reached England in 1940. Str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calgary, Canada
Calgary ( ) is the largest city in the western Canadian province of Alberta and the largest metro area of the three Prairie Provinces. As of 2021, the city proper had a population of 1,306,784 and a metropolitan population of 1,481,806, making it the third-largest city and fifth-largest metropolitan area in Canada. Calgary is situated at the confluence of the Bow River and the Elbow River in the south of the province, in the transitional area between the Rocky Mountain Foothills and the Canadian Prairies, about east of the front ranges of the Canadian Rockies, roughly south of the provincial capital of Edmonton and approximately north of the Canada–United States border. The city anchors the south end of the Statistics Canada-defined urban area, the Calgary–Edmonton Corridor. Calgary's economy includes activity in the energy, financial services, film and television, transportation and logistics, technology, manufacturing, aerospace, health and wellness, retail, and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on Earth. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall, used a spark-gap transmitter to produce a signal with a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marconi Research Centre
Marconi Research Centre is the former name of the current BAE Systems Applied Intelligence Laboratories facility at Great Baddow in Essex, United Kingdom. Under its earlier name, research at this site spanned military and civilian technology covering the full range of products offered by GEC-Marconi, including radio, radar, telecommunications, mechatronics and microelectronics. Origins Marconi Company chose to establish itself in Chelmsford shortly after the company was founded in 1897. It first acquired the former silk-works on Hall Street before expanding to a new factory, the New Street Works, in 1912. At the same time a formal Research Department was founded under the auspices of Charles Samuel Franklin near the original Hall Street works. The facilities were placed under the direction of the Admiralty at the outbreak of the First World War. When the Marconi Company resumed control in 1919, it was two years before the Research Department was reconstituted under H. J. Rou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Dönitz
Karl Dönitz (sometimes spelled Doenitz; ; 16 September 1891 24 December 1980) was a Nazi Germany, German admiral who briefly succeeded Adolf Hitler as head of state in May 1945, holding the position until the dissolution of the Flensburg Government following German Instrument of Surrender, Germany's unconditional surrender to the Allies of World War II, Allies days later. As Oberbefehlshaber der Marine, Supreme Commander of the Navy beginning in 1943, he played a major role in the naval history of World War II. He began his career in the Imperial German Navy before World War I. In 1918, he was commanding , and was taken prisoner of war by British forces. While in a POW camp, he formulated what he later called Wolfpack (naval tactic), ''Rudeltaktik'' ("pack tactic", commonly called "wolfpack"). By the start of the Second World War, Dönitz was supreme commander of the ''Kriegsmarine'' U-boat arm ( (BdU)). In January 1943, Dönitz achieved the rank of (grand admiral) and repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jürgen Rohwer
Jürgen Rohwer (24 May 192424 July 2015) was a German military historian and professor of history at the University of Stuttgart. Rohwer wrote over 400 books and essays on World War II naval history and military intelligence, which gained him worldwide recognition as a prominent historian and a leading authority on U-boats. Biography Rohwer was born in Friedrichroda. After leaving school in 1942, he entered the Kriegsmarine as an officer candidate (crew VI/42). During World War II he served on several German warships, e.g. destroyer Z24, ''Sperrbrecher'' 104/Martha, and minesweeper M-502. After the end of the war he left service and studied history at the University of Hamburg. During that time he got into contact with Günter Hessler son in law to Karl Dönitz and was commissioned by the British Royal Navy to write an official account of the U-boat war 1939–1945. In 1954 he received his doctoral degree at Hamburg University for his dissertation on German-American relatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Codebreaking
Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown. In addition to mathematical analysis of cryptographic algorithms, cryptanalysis includes the study of side-channel attacks that do not target weaknesses in the cryptographic algorithms themselves, but instead exploit weaknesses in their implementation. Even though the goal has been the same, the methods and techniques of cryptanalysis have changed drastically through the history of cryptography, adapting to increasing cryptographic complexity, ranging from the pen-and-paper methods of the past, through machines like the British Bombes and Colossus computers at Bletchley Park in World War II, to the mathematically advanced com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in the period before and during World War II. A key development was the cavity magnetron in the United Kingdom, which allowed the creation of relatively small systems with sub-meter resolution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay Blair Jr
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a dictatorship. Under Hitler's rule, Germany quickly became a totalitarian state where nearly all aspects of life were controlled by the government. The Third Reich, meaning "Third Realm" or "Third Empire", alluded to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which Hitler and the Nazis referred to as the Thousand-Year Reich, ended in May 1945 after just 12 years when the Allies of World War II, Allies defeated Germany, End of World War II in Europe, ending World War II in Europe. On 30 January 1933, H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Reflection
In telecommunications, signal reflection occurs when a signal is transmitted along a transmission medium, such as a copper cable or an optical fiber. Some of the signal power may be reflected back to its origin rather than being carried all the way along the cable to the far end. This happens because imperfections in the cable cause impedance mismatches and non-linear changes in the cable characteristics. These abrupt changes in characteristics cause some of the transmitted signal to be reflected. In radio frequency (RF) practice this is often measured in a dimensionless ratio known as voltage standing wave ratio (VSWR) with a VSWR bridge. The ratio of energy bounced back depends on the impedance mismatch. Mathematically, it is defined using the reflection coefficient. Because the principles are the same, this concept is perhaps easiest to understand when considering an optical fiber. Imperfections in the glass create mirrors that reflect the light back along the fiber. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
