RDF to RADAR [Main Title]

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  • Title: RDF to RADAR [Main Title]
  • Film Number: AMY 450
  • Other titles:
  • Summary: A documentary film for a specialist audience about the development of radar by British scientists from 1935 to 1945, illustrated with sophisticated graphics, animated maps and actuality footage.
  • Description: START 01:00:00 Reel 1. The film opens with views of TRE establishments at Orford, Bawdsey, Dundee, Swanage and Malvern where from 1935 to 1945 British scientists and technicians developed RDF (radio direction finding), subsequently known as RADAR (radio detection and ranging). A caption: "This film provides a historical record for technical audiences associated with the development of Radar and a summarised introduction to detailed TRE Radar films already produced". Radar's enormous contribution to victory over Nazi Germany is outlined with graphics. Intertitle 'The Defensive'. With the aid of graphics and brief shots of research stations and radio transmitters, the film describes how the threat of German rearmament led in January 1935 to a review by the Tizard Committee for the Scientific Survey of Air Defence into existing methods of detecting approaching enemy aircraft, its recommendation that radio location offered the best means of solving this problem, and the first experiments with high-powered radio transmitters by TRE technicians at Slough and Daventry to demonstrate the feasibility of the concept. Maps, graphics and actuality footage illustrate the techniques employed in top-secret experiments by TRE scientists at Orford on the Suffolk coast from May 1935 onwards to turn the concept into reality so that, by early 1937, it was possible to measure the distance, height and direction of an approaching aircraft by RDF. The first field trials with 26 metre-wavelength RDF were carried out at Dunkirk in Kent. 01:05:28 A mix of actuality footage and animated maps illustrating the work carried out by TRE Bawdsey to develope the first type of mobile radar station that would be used in the Middle East. Shots of the first four 240 foot-tall towers in the CHAIN HOME (CH) radar system covering London and the Thames Estuary that were built in 1937-38. Dramatic headlines from newspapers and animated maps showing the creation of a network of CH stations and three mobile RDF installations covering the Thames, Forth, Humber and Wash estuaries in time for the September 1938 Munich Crisis and its subsequent expansion by the following May. 01:07:01 Graphics and animated maps showing the work by TRE Bawdsey and No. 2 Installation Unit at Kidbrooke to create an early warning system along Britain's east coast with CH stations by September 1939 and its expansion to cover the whole of the British Isles. Actuality footage showing a Coastal Defence (CD) RDF installation with the first fully rotating aerials capable of detecting low-flying aircraft and animated maps illustrating the network of CD stations in the Orkneys and Shetlands to monitor the approach of enemy warships. Graphics explaining the modification of the CH chain of stations to share CD capacity by utilising a 'split-beam' radio transmissions and becoming CHL (Chain Home Low) to detect aircraft at both low and high altitudes. Graphics explaining the principle technical features of the first IFF (Identification Friend or Foe) system developed by TRE Bawdsey. 01:09:46 Reel 2. Graphic showing the first experiments with 1.5 metre wavelength transmissions to develope an AI (Airborne Interception) and ASV (Air to Surface Vessel) in 1938-39. A quickly-cut sequence showing an RAF radar operator, WAAF plotters at a sector control station and Vickers Supermarine Spitfires taking off from airstrips illustrates how an effective early warning system for the whole of the British Isles played a decisive part in winning the Battle of Britain. 01:10:47 'The Defensive: The Night Battle'. Brief shots of the building in Dundee used by personnel from Bawdsey and the new location for TRE Slough during the evacuation of essential scientific personnel from south-east England in the summer of 1940 at Swanage. Graphics and actuality footage showing a Bristol Beaufighter night-fighter in flight showing TRE's development of a radar capable of locating lone enemy night raiders over Britain, the Airborne Interception (AI) Mark IV 1.5 metre radar which could detect enemy aircraft at altitudes ranging from 20,000 feet to 600 feet but had extremely short range. 01:12:50 A mix of graphics and actuality footage featuring a Bristol Beaufighter in flight and a shot-down Junkers Ju 88 bomber illustrates the establishment of Ground Control Interception (GCI) stations at radar sites to guide night-fighters to their targets, the invention of the first PPI (Plan Position Indicator) tube and the development of rotating GCI radar aerials by TRE at Worth Matravers resulting in the introduction of six GCI stations by early 1941, each manned by three controllers able to direct night-fighters onto separate targets. Actuality shots of a new generation of GCI 50 centimetre radar, known as AMES (Air Ministry Experimental Station) Type 11 which was developed to defeat German jamming of 1.5 metre radar transmissions by using the 50 centimetre wavelength used by enemy radar, illustrated here with a WURZBURG radar. Graphics and actuality footage showing the first successful use by the Germans of radar jamming equipment during the February 1942 'Channel Dash' by the German battlecruisers Scharnhorst and Gneisenau (accompanied by the heavy cruiser Prinz Eugen). 01:15:31 Graphics illustrating the development of radar operating on shorter wavelengths and with a very narrow beam to replace all existing CH, CHL, GCI and AI radar systems with equipment that guaranteed both accuracy and protection from enemy jamming. Shots of the two inventions that made this possible, the cavity magnetron and the chrystrom (?) valves, which were available by the summer of 1940. Graphics supplemented by brief actuality shots showing how centimetric wavelength radar operated, its compactness - which facilitated its use in aircraft - and illustrating the development of the Mk VII and Mk VIII AI radar. Actuality footage showing the spiral scan system with a PPI display showing range and elevation simultaneously used by RAF Bristol Beaufighter and de Havilland Mosquito night-fighters equipped with the Mk VII and Mk VIII AI radar in 1942-43. Actuality footage showing RAF ground crew at work on a AI-equipped Bristol Beaufighter and RAF radar technicians attending a lecture to illustrate the role of the Post Design Services (PDS) to train frontline RAF personnel how to maintain and operate the latest AI gear. Actuality footage of the helical scan system with two PPI screens that was developed by the Americans as the SCR-720 and introduced later in the war. Graphics with a description of the LUCERO centimetric IFF system to cope with ground beacons operating on metre wavelengths. 01:20:13 Reel 3. Intertitle 'Sea War Phase I'. A mix of graphics and actuality footage showing early experiments at Bawdsey with airborne radar that could detect ships at sea and the adoption by RAF Coastal Command of the ASV (Air to Surface Vessel) Mk I on its Lockheed Hudson aircraft and Short Sunderland flying boats in 1939-40. Actuality footage and graphics illustrating the longer-range ASV Mk II, introduced in July 1941 and used successfully to locate convoys at sea and to hunt German shipping at night (illustrated here by camera-gun footage showing a low-level strafing attack on an enemy vessel by daylight) and the addition of Leigh Lights to Vickers Wellingtons with ASV Mk II that greatly facilitated night attacks on surfaced U-Boats during the First Battle of the Bay of Biscay in June 1942. 01:21:57 Intertitle 'Allied Air Offensive.' Graphics and animated maps illustrating how GEE, the first British ground-based radio navigation system to enter service, allowed RAF bombers to locate bombing targets in western half of Germany. Operational by early 1942, GEE was first used in an RAF raid on Essen in March 1942, illustrated here by shots of RAF ground crew loading bombs into the bomb bay of an Avro Lancaster and a Lancaster taking off from a runway. Graphics illustrating how by early 1943 GEE was vulnerable to jamming by the Germans and actuality shots of a new version, GEE Mk II, which allowed its operator to switch frequencies, introduced in time for the famous Dambusters raid in April 1943, illustrated here in a short sequence featuring an aerial reconnaissance photograph of the Moehne Dam, studio shots of a model dam breaking up and releasing flood waters and German troops helping flood victims. Graphics showing how GEE Mk II allowed large numbers of RAF bombers to saturate enemy air defences but lacked the precision for 'blind-bombing'. 01:24:02 Animated maps and graphics showing how OBOE, a ground control-based 'blind-bombing' system, devised in May 1941, directed a bomber onto its target by range measurements transmitted from CAT and MOUSE, two ground stations in England. OBOE was used for the first time against the Krupp works in Essen in December 1942. Technical difficulties with GEE limited its use to all but a few aircraft at any one time so Bomber Command created the Pathfinder Force to locate and illuminate targets ahead of the main bomber force, illustrated here by shots showing a de Havilland Mosquito light bomber being bombed-up and taking off from a runway. Operational bombing footage of a night raid on a German city purports to illustrate the Pathfinders' first mission, an attack on Essen in March 1943 in ten-tenths cloud. Graphics showing how an aircraft equipped with OBOE's replacement, the H system, could acquire an accurate 'fix' on its target in the final stages of its approach, thus reducing its vulnerability to enemy jamming. Devised in 1940, H consisted of a modified GEE system to become GEE-H. Illustrated here with shots of an RAF North American Mitchell bomber with GEE-H aerials, the GEE-H operator hunched over his display screen and the Mitchell in flight, the film describes how GEE-H was a highly accurate navigational guidance system, used for example to lay aerial mines off the coast of France just before D-Day. 01:27:23 The main drawback of OBOE, GEE-H and GEE was their limited range. What was really needed was a self-contained radar system that operated independently of ground stations. Advances in centimetric radar made this type of apparatus possible. Using graphics and actuality footage of both the equipment and PPI displays, the film describes the research and development programme at TRE Malvern that produced the H2S system capable of picking up geographical features such as shorelines and built-up areas. An easy system to operate, it entered service early in 1942 and by the autumn of 1943, one in every six of Bomber Command's aircraft were equipped with H2S radar. Later improvements to H2S like the 3cm X-Band shortwave frequency technique greatly increased the resolution of the PPI display and made the accurate bombing of Berlin possible. Similarly, OBOE was enhanced by adapting it to centimetric wavelength, leading in the introduction of OBOE Mk II M in the spring of 1944. 01:29:11 Reel 4. With the help of graphics, the film explains how radar has been used to alert RAF bomber crews to approaching night-fighters, with warning devices such as BOOZER, FISHPOND, MONICA (none of these devices is shown) and a radar-controlled gun sight known by its acronym AGLT (Airborne Gun-laying in Turrets), briefly seen here with an impressive shot of a large formation of Avro Lancasters in flight. Graphics showing the active measures to disrupt the enemy's air defences - jamming his radar frequencies and sending in intruders to shoot down his night-fighters; the actuality footage used to illustrate RAF intruders shooting down Luftwaffe night-fighters shows a low-flying US P-40 firing its wing-mounted machine-gun and Junkers Ju 88 bombers being shot down at some point early in the war. Actuality footage of MANDREL, the airborne electronic jamming equipment used to confuse the German FREYA early warning radar, in action and graphics showing how MOONSHINE mimicked and enlarged the radar echoes obtained by FREYA to give the impression that a large aircraft formation was approaching. Actuality footage of strips of foil paper, code-named WINDOW, being released from a Vickers Welllington bomber aircraft and graphics showing the mass of confusing radar echoes created by WINDOW on a German WURZBURG radar screen. Although developed in 1941, WINDOW was not used until the July 1943 raid on Hamburg for fear that the enemy would also use it but the RAF would continue to use it until the end of the war in Europe. 01:31:27 Actuality footage and graphics illustrating CARPET II, a device that automatically tracked enemy radar frequencies, locked on to them and jammed them for a limited period and SERRATE, first used in the autumn of 1943 by RAF night-fighters to home in on enemy AI transmissions. Concerns that the AI Mk VIII would not be able to cope with high concentrations of WINDOW led to the modification by the British of the US-manufactured SCR-720 and its introduction by the RAF in November 1943 as the AI Mk X, used by intruder flights defending RAF bombers over Germany. 01:32:48 Intertitle 'Sea War Phase II'. The build-up of US and Canadian troops in Great Britain for the invasion of Europe, illustrated here with brief actuality shots, required the elimination of the U-Boat threat. Graphics and live-action footage showing an RAF Coastal Command Vickers Wellington equipped with a Leigh Light and an ASV (Air to Surface Vessel) Mk III, based on the H2S centimetric system, attacking a U-Boat on the surface at night (faked shots). A graphics sequence showing the part played by the new ASV radar was responsible for winning the second Battle of the Bay of Biscay in June 1943, followed by a mixed actuality and graphics sequence showing how an even more sophisticated device, the Mk VIA, automatically guided the Leigh Light onto its target. 01:34:26 In 1942, work on the X-Band 3 centimetre radar led to the development of the ASV X set, as seen here fitted to Fairey Swordfish Mk III biplanes landing on the deck of an escort carrier and in flight over the sea. Known officially as the ASV Mk XI, the radar equipment was sufficiently small to be used by carrier-borne Fleet Air Arm aircraft as a navigational aid and saw a good deal of service on the Arctic convoys and in the English Channel in 1944. 01:35:10 Intertitle 'D-Day'. A concluding section illustrated with animated maps, quickly-cut actuality scenes and graphics showing the part played by radar in the Allied air offensive over Germany and the invasion of Europe in June 1944. Radar and electronic jamming played their part in guaranteeing Allied success on D-Day, especially with a decoy mission illustrated here with an animated map and graphics in which aircraft, guided by GEE and GEE-H, dropped bundles of WINDOW over the English Channel to simulate the approach of an invasion fleet on a section of the French coast near Dieppe. Actuality shots showing a Handley-Page Halifax bomber dropping parachute supplies illustrate the role of REBECCA/EUREKA guidance beacons in aiding the French Resistance. Over an animated map showing the gradual advance of Allied armies in North-West Europe from June 1944 to May 1945, the commentary asserts radar's part in winning the war. END 01:39:01
  • Alternative Title:
  • Colour: B&W
  • Digitised: Yes
  • Object_Number: AMY 450
  • Sound: Sound
  • Access Conditions: Film: IWM (AMY 450)
  • Featured Period: 1939-1945
  • Production Date: 1946-1946
  • Production Country:GB
  • Production Details:Ministry of Aircraft Production (MAP) (Production sponsor) Telecommunications Research (Production company) Dewhurst, H (Production individual) Segaller, A D (Production individual) Waley, H D (Production individual) Dewhurst, H (Production individual) Segaller, A D (Production individual) Waley, H D (Production individual) Dewhurst, H (Production individual) Segaller, A D (Production individual) Waley, H D (Production individual) Dale, Adeline (Production individual) Dale, Adeline (Production individual) Dahl, L (Production individual) Sedgewick, Sally (Production individual) Allison, Joanna (Production individual) Francis, Farley (Production individual) Taylor, G S (Production individual) Isaacs, Phyllis (Production individual) Swain, S A H (Production individual) Browning, J (Production individual) Tutchings, A (Production individual) Walton, William (Production individual) Snagge, John Derrick Mordaunt (Production cast)
  • Personalities, Units and Organisations:
  • Keywords:
  • Physical Characteristics:Colour format: B&W Sound format: Sound Soundtrack language: English Title language: English
  • Technical Details:Footage: 3745 ft; Running time: 39 mins 56 secs
  • HD Media:Yes
  • Link to IWM Collections page:

    AMY 450

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