|
Type 273 Radar
The Type 271 was a surface search radar used by the List of World War II British naval radar, Royal Navy and allies during World War II. The first widely used naval microwave-frequency system, it was equipped with an antenna small enough to allow it to be mounted on small ships like corvettes and frigates, while its improved optical resolution, resolution over earlier radars allowed it to pick up a surfaced U-boat at around and its periscope alone at . The prototype, 271X, was fitted to HMS Orchis (K76), HMS ''Orchis'' in March 1941 and declared operational in May. Small numbers became available during the year, with about thirty sets in operation by October. The design spawned two larger versions, Type 272 for destroyers and small cruisers, and Type 273 for larger cruisers and battleships. The 272 was not considered successful and not widely used. The 273 differed in having larger and more focused antennas, providing higher gain (antenna), gain and thus longer range. This prov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ASV Mark III Radar
Radar, Air-to-Surface Vessel, Mark III, or ASV Mk. III for short, was a surface search radar system used by RAF Coastal Command during World War II. It was a slightly modified version of the H2S radar used by RAF Bomber Command, with minor changes to the antenna to make it more useful for the anti-submarine role. It was Coastal Command's primary radar from the spring of 1943 until the end of the war. Several improved versions were introduced, notably the ASV Mark VI, which replaced most Mk. IIIs from 1944 and ASV Mark VII radar, which saw only limited use until the post-war era. Coastal Command's first radar was ASV Mark I, which began experimental use in 1939. Minor improvements were made for the Mark II in 1940 but it was not widely available until late 1941. Having realized that the RAF was using radar to detect their U-boats, in the summer of 1942 the Germans introduced the Metox radar detector to listen for their signals. This gave the submarine a warning of the aircraft appro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength). It lies between the medium frequency band (MF) and the bottom of the VHF band. Radio waves in the shortwave band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or "skip" propagation. Thus shortwave radio can be used for communication over very long distances, in contrast to radio waves of higher frequency, which travel in straight lines (line-of-sight propagation) and are generally limited by the visual horizon, about 64 km (40 miles). Shortwave broadcasts of radio pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies that humans can hear (though these are not electromagnetic) and the lower limit of infrared frequencies, and also encompasses the microwave range. These are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves, so they are used in radio technology, among other uses. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type 79 Radar
The Type 79 radar was a British naval early-warning radar developed before World War II. It was the first radar system deployed by the Royal Navy. The first version of this radar, Type 79X, was mounted on the RN Signal School's tender, the minesweeper , in October 1936. This equipment used a frequency of 75 MHz and a wavelength of 4 metres and its antennae were strung between the ship's masts. They detected an aircraft at an altitude of and a range of during tests in July 1937. Improved versions, Type 79Y, were developed the following year that used a frequency of 43 MHz (7 metres). It required separate transmitting and receiving antennas and had a power output between 15 and 20 kW. The first set was installed in September 1938 aboard the light cruiser and gave detection ranges up to for an aircraft at . A second set was mounted on the battleship the following month, but it was not tested until January 1939. A more powerful version, Type 79Z, was fitted to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portsmouth
Portsmouth ( ) is a port city status in the United Kingdom, city and unitary authority in Hampshire, England. Most of Portsmouth is located on Portsea Island, off the south coast of England in the Solent, making Portsmouth the only city in England not located primarily on the Great Britain, mainland. The city is located south-east of Southampton, west of Brighton and Hove and south-west of London. With a population last recorded at 208,100, it is the most densely populated city in the United Kingdom. Portsmouth forms part of the South Hampshire urban area with Gosport, Borough of Fareham, Fareham, Borough of Havant, Havant, Borough of Eastleigh, Eastleigh and Southampton. Portsmouth's history can be traced to Roman Britain, Roman times and has been a significant Royal Navy dockyard and base for centuries. Portsmouth was founded by Anglo-Norman merchant Jean de Gisors in the south-west area of Portsea Island, a location now known as Old Portsmouth. Around this time, de Gis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Ministry
The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force and civil aviation that existed from 1918 to 1964. It was under the political authority of the Secretary of State for Air. Organisations before the Air Ministry The Air Committee On 13 April 1912, less than two weeks after the creation of the Royal Flying Corps (which initially consisted of both a naval and a military wing), an Air Committee was established to act as an intermediary between the Admiralty and the War Office in matters relating to aviation. The new Air Committee was composed of representatives of the two war ministries, and although it could make recommendations, it lacked executive authority. The recommendations of the Air Committee had to be ratified by the Admiralty Board and the Imperial General Staff and, in consequence, the Committee was not particularly effective. The increasing separation of army and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Watson-Watt
Sir Robert Alexander Watson-Watt (13 April 1892 – 5 December 1973) was a Scottish radio engineer and pioneer of radio direction finding and radar technology. Watt began his career in radio physics with a job at the Met Office, where he began looking for accurate ways to track thunderstorms using the radio waves given off by lightning. This led to the 1920s development of a system later known as high-frequency direction finding (HFDF or "huff-duff"). Although well publicized at the time, the system's enormous military potential was not developed until the late 1930s. Huff-duff allowed operators to determine the location of an enemy radio transmitter in seconds and it became a major part of the network of systems that helped defeat the threat of German U-boats during World War II. It is estimated that huff-duff was used in about a quarter of all attacks on U-boats. In 1935, Watt was asked to comment on reports of a German death ray based on radio. Watt and his assistant A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Navy
The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom of England, English and Kingdom of Scotland, Scottish kings from the early Middle Ages, medieval period, the first major maritime engagements were fought in the Hundred Years' War against Kingdom of France, France. The modern Royal Navy traces its origins to the English Navy of the early 16th century; the oldest of the British Armed Forces, UK's armed services, it is consequently known as the Senior Service. From the early 18th century until the World War II, Second World War, it was the world's most powerful navy. The Royal Navy played a key part in establishing and defending the British Empire, and four Imperial fortress colonies and a string of imperial bases and coaling stations secured the Royal Navy's ability to assert naval superior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battle Of The North Cape
The Battle of the North Cape was a Second World War naval battle that occurred on 26 December 1943, as part of the Arctic campaign. The , on an operation to attack Arctic convoys of war materiel from the western Allies to the Soviet Union, was brought to battle and sunk by the Royal Navy's battleship with cruisers and destroyers, including an onslaught from the destroyer of the exiled Royal Norwegian Navy, off the North Cape, Norway. The battle was the last between British and German big-gun capital ships. The outcome increased the British advantage in major surface units. It was also the penultimate engagement between battleships in history, the last being the October 1944 Battle of Surigao Strait. Background Since August 1941, the western Allies had run convoys of ships from the United Kingdom and Iceland to the northern ports of the Soviet Union to provide essential supplies for their war effort on the Eastern Front. These endured much hardship, frequently attacked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Battleship Scharnhorst
was a German capital ship, alternatively described as a battleship or battlecruiser, of Nazi Germany's ''Kriegsmarine''. She was the lead ship of her class, which included her sister ship . The ship was built at the ''Kriegsmarinewerft'' dockyard in Wilhelmshaven; she was laid down on 15 June 1935 and launched a year and four months later on 3 October 1936. Completed in January 1939, the ship was armed with a main battery of nine 28 cm (11 in) C/34 guns in three triple turrets. Plans to replace these weapons with six 38 cm (15 in) SK C/34 guns in twin turrets were never carried out. and operated together for much of the early portion of World War II, including sorties into the Atlantic to raid British merchant shipping. During her first operation in November 1939, sank the armed merchant cruiser in a short engagement. and participated in Operation Weserübung, the German invasion of Norway, from April to June 1940. During operations off Norway, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HMS Duke Of York (17)
HMS ''Duke of York'' was a battleship of the Royal Navy. Keel laying, Laid down in May 1937, the ship was constructed by John Brown and Company at Clydebank, and Ship commissioning, commissioned into the Royal Navy on 4 November 1941, subsequently seeing combat service during the Second World War. In mid-December 1941, ''Duke of York'' transported Prime Minister Winston Churchill to the United States to meet President Franklin D. Roosevelt. Between March and September 1942 ''Duke of York'' was involved with convoy escort duties, including as flagship of the Heavy Covering Force of Convoy PQ-17, but in October she was dispatched to Gibraltar where she became the flagship of Force H. In October 1942, ''Duke of York'' was involved in the Operation Torch, Allied invasion of North Africa, but saw little action as her role only required her to protect the accompanying aircraft carriers. After the invasion, ''Duke of York'' was involved in Operations Camera and Governor, which were d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
