High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency
High frequency (HF) refers to a radio band that can effectively communicate over long distances; for example, between U-boats and their land-based headquarters. HF/DF was primarily used to catch enemy radios while they transmitted, although it was also used to locate friendly aircraft as a navigation aid. The basic technique remains in use to this day as one of the fundamental disciplines of signals intelligence, although typically incorporated into a larger suite of radio systems and radars instead of being a stand-alone system. HF/DF used a set of antennas to receive the same signal in slightly different locations or angles, and then used those slight differences in the signal to display the bearing to the transmitter on an oscilloscope display
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HMS Belfast is a Town-class light cruiser that was built for the Royal Navy. It is now permanently moored as a museum ship on the River Thames in London
London and is operated by the Imperial War Museum. Construction of Belfast, the first ship in the Royal Navy
Royal Navy to be named after the capital city of Northern Ireland
Northern Ireland and one of ten Town-class cruisers, began in December 1936. She was launched on St Patrick's Day 1938. Commissioned in early August 1939 shortly before the outbreak of the Second World War, Belfast
Belfast was initially part of the British naval blockade against Germany. In November 1939, Belfast
Belfast struck a German mine and spent more than two years undergoing extensive repairs. Belfast
Belfast returned to action in November 1942 with improved firepower, radar equipment, and armour
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Radar
Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. 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 object(s). Radio
Radio waves (pulsed or continuous) from the transmitter reflect off the object and return to the receiver, giving information about the object's location and speed. Radar
Radar was developed secretly for military use by several nations in the period before and during World War II
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Aldershot
Aldershot (/ˈɔːldərʃɒt/) is a town in the Rushmoor
Rushmoor district of Hampshire, England. It lies on heathland in the extreme northeast corner of the county, about 31.8 mi (51.2 km) southwest of London. The area is administered by Rushmoor
Rushmoor Borough Council
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Ditton Park, Ditton Manor House or Ditton Park
Ditton Park House was the manor house and private feudal demesne of the lord of the Manor of Ditton, and refers today to the rebuilt building and smaller grounds towards the edge of the town of Slough
Slough in England. A key feature is its centuries-old moat which extends to most of the adjoining lawns and garden. Park areas extend to the north and west of the moat. Ditton Park
Ditton Park House and its courtyard walls, stables and observatory are Grade II listed on the National Heritage List for England
England (i.e. in the initial category).[1]Contents1 History and architecture 2 Location 3 References 4 External linksHistory and architecture[edit]Queen Mary (I) of England, Portrait by Antonis Mor, 1554The Duchess of Buccleuch by Thomas Gainsborough, c
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Slough
Slough (/ˈslaʊ/ ( listen)) is a large town in Berkshire, England, on the western fringes of the Greater London
London Urban Area, 20 miles (32 km) west of central London, 3 miles (5 km) north of Windsor, 7 miles (11 km) east of Maidenhead, 12 miles (19 km) south-east of High Wycombe
High Wycombe and 21 miles (34 km) north-east of the county town of Reading. Sitting at the gateway between the Thames Valley
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Thames Valley and London
London and at the intersection of the M4, M40 and M25 motorways, it offers easy road access to the rest of the UK. The A4 and the Great Western Main Line
Great Western Main Line pass through the town, which was historically part of neighbouring Buckinghamshire
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The National Physical Laboratory (NPL) is the national measurement standards laboratory for the United Kingdom, based at Bushy Park
Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.Contents1 Description 2 Operation 3 Buildings 4 Researchers 5 Research5.1 Atomic clocks 5.2 Computing 5.3 Packet switching6 Directors of NPL 7 See also 8 References 9 External linksDescription[edit]The electricity Division of the National Physical Laboratory in 1944NPL is known for its UK leadership in measurement and materials science. Since 1900, when Bushy House
Bushy House was selected as the site of NPL, it has developed and maintained the primary national measurement standards
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The Adcock antenna
Adcock antenna is an antenna array consisting of four equidistant vertical elements which can be used to transmit or receive directional radio waves. The Adcock array was invented and patented by British engineer Frank Adcock in 1919 as British Patent
Patent No. 130,490, and has been used for a variety of applications, both civilian and military, ever since.[1][2][3] Although originally conceived for receiving Low Frequency (LF) waves, it has also been used for transmitting, and has since been adapted for use at much higher frequencies, up to Ultra High Frequency (UHF).[4][5] In the early 1930s, the Adcock antenna
Adcock antenna (transmitting in the LF/MF bands) became a key feature of the newly created radio navigation system for aviation
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Nokia
Nokia Bell Labs
Bell Labs (formerly named AT&T Bell Laboratories, Bell Telephone
Telephone Laboratories and Bell Labs) is an American research and scientific development company, owned by Finnish company Nokia. Its headquarters are located in Murray Hill, New Jersey, in addition to other laboratories around the rest of the United States
United States and in other countries. The historic laboratory originated in the late 19th century as the Volta Laboratory and Bureau
Volta Laboratory and Bureau created by Alexander Graham Bell
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A phosphor, most generally, is a substance that exhibits the phenomenon of luminescence. Somewhat confusingly, this includes both phosphorescent materials, which show a slow decay in brightness (> 1 ms), and fluorescent materials, where the emission decay takes place over tens of nanoseconds. Phosphorescent materials are known for their use in radar screens and glow-in-the-dark materials, whereas fluorescent materials are common in cathode ray tube (CRT) and plasma video display screens, fluorescent lights, sensors, and white LEDs. Phosphors are often transition-metal compounds or rare-earth compounds of various types. The most common uses of phosphors are in CRT displays and fluorescent lights
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Pip-squeak was a simple radio navigation system used by the British Royal Air Force
Royal Air Force during the early part of World War II. Pip-squeak used an aircraft's voice radio set to periodically send out a 1 kHz tone which was picked up by ground-based high-frequency direction finding (HFDF, "huff-duff") receivers. Using three HFDF measurements, observers could determine the location of friendly aircraft using triangulation. Pip-squeak was used by fighter aircraft during the Battle of Britain as part of the Dowding system, where it provided the primary means of locating friendly forces, and indirectly providing identification friend or foe (IFF). At the time, radar systems were sited on the shore and did not provide coverage over the inland areas, so IFF systems that produced unique radar images were not always useful for directing interceptions
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Chain Home, or CH for short, was the codename for the ring of coastal Early Warning radar stations built by the Royal Air Force
Royal Air Force (RAF) before and during the Second World War to detect and track aircraft.[1] The term also referred to the radar equipment itself, until it was given the official name Air Ministry Experimental Station Type 1 (AMES Type 1) in 1940
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The Royal Air Force
Royal Air Force (RAF) is the United Kingdom's aerial warfare force. Formed towards the end of the First World War
First World War on 1 April 1918,[2] it is the oldest independent air force in the world.[3] Following victory over the Central Powers
Central Powers in 1918 the RAF emerged as, at the time, the largest air force in the world.[4] Since its formation, the RAF has taken a significant role in British military history
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The British Isles
British Isles are a group of islands off the north-western coast of continental Europe
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Europe that consist of the islands of Great Britain, Ireland
Ireland and over six thousand smaller isles.[7] Situated in the North Atlantic, the islands have a total area of approximately 315,159 km2,[5] and a combined population of just under 70 million. Two sovereign states are located on the islands: the Republic of Ireland
Ireland (which covers roughly five-sixths of the island of Ireland)[8] and the United Kingdom
United Kingdom of Great Britain
Great Britain and Northern Ireland
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The Royal Observer Corps
Royal Observer Corps (ROC) was a civil defence organisation intended for the visual detection, identification, tracking and reporting of aircraft over Great Britain. It operated in the United Kingdom between 29 October 1925 and 31 December 1995, when the Corps' civilian volunteers were stood down. (ROC headquarters staff at RAF Bentley Priory stood down on 31 March 1996)
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