Würzburg radar
Encyclopedia
The Würzburg radar was the primary ground-based gun laying
radar
for both the Luftwaffe
and the German Army
during World War II
. Initial development took place before the war, entering service in 1940. Eventually over 4,000 Würzburgs of various models were produced. It took its name from the city of Würzburg
as the project leader liked geographical names.
met with German radar researchers, notably Dr. Rudolf Kühnhold
of the Communications Research Institute of the German Navy
and Dr. Hans Hollmann
, an expert in microwave
s, who informed them of their work on an early warning radar
. Telefunken's director of research, Dr. Wilhelm Runge
, was unimpressed, and dismissed the idea as science fiction
. The developers then went their own way and formed GEMA, eventually collaborating with Lorenz on the development of the Freya
and Seetakt
systems.
By the spring of 1935 GEMA's successes made it clear to Runge that the idea was workable after all, so he immediately started a crash program at Telefunken to develop radar systems of their own. With Lorenz already making progress on the early warning front, Runge had the Telefunken team concentrate on a short-range gun laying system instead. Management apparently felt it to be as uninteresting as Runge had a year earlier, and assigned it a low priority for development. Nevertheless, development started and by the summer they had built a working experimental unit working in the 50 cm band that was able to generate strong returns off a target Junkers Ju 52
. By the next summer, the experimental setup had been developed into a real prototype machine known as the Darmstadt, which offered a range accuracy of 50 m at 5 km, not nearly enough for gun laying. Attitudes changed in late 1938, when a full development contract was received from the Luftwaffe.
The resulting system, known as the FuMG 62, as well as the prototype system FuMG 39T Darmstadt were demonstrated to Hitler at Rechlin
in July 1939. The Telefunken team developed an accurate system based on a klystron
microwave
tube operating in the range of 54 to 53 cm (553 to 566 MHz) – an extremely short wavelength for the time – with a pulse length of 2 microseconds, a peak power of 7 to 11 kW, and a PRF
of 3,750 Hz. It had a maximum range of about 29 kilometres (18 mi), and was accurate to about 25 m in range. Würzburg used a 3 m paraboloid
dish antenna mounted on a wheeled trailer, and the dish could be "folded" along the horizontal midline for travel. The system was first accepted into service in 1940, and eventually 4,000 of this basic layout were delivered.
Several versions of the basic Würzburg system were deployed over the course of the war. The first, Würzburg A, was operated manually and required the operators to pinpoint the target by maintaining a maximum signal on their oscilloscope
display. Since the signal strength changed on its own for various reasons as well as being on or off target, this was not very accurate, and generally required the use of a searchlight
to spot the target once the radar had settled on an approximate position. Nevertheless one of the very first Würzburgs claimed a plane in May 1940 by orally relaying commands to a flak unit. An experimental Würzburg B added an infra-red detector for "fine tuning", but in general these devices proved to be unusable and production was discontinued.
Würzburg C featured lobe switching
to improve aiming accuracy. The C model was aimed by sending the signal out of one of two slightly off-centre feed horns in the middle of the antenna, the signal being switched rapidly between the two horns. Both returns were sent to an oscilloscope display, slightly delaying the signal from one of the horns. The result appeared as two closely separated "spikes" which the operator attempted to keep at the same height on the display. This system offered much faster feedback on changes in target position, and since any change in signal strength would affect both lobes equally, the operator no longer had to "hunt" for the maximum signal point. An almost identical system was used in the United States' first gun-laying radar, the SCR-268
.
The Würzburg D, introduced in 1941, added a conical scanning
system, using an offset receiver feed called a "Quirl" (German for whisk
) that spun at 25 Hz. The resulting signal was slightly offset from the centreline of the dish, rotating around the axis and overlapping it in the centre. If the target aircraft was to one side of the antenna's axis, the system would see the strength of the signal grow and fade as the beam swept across it, allowing the system to move the dish in the direction of the maximum signal and thereby track the target. Additionally, the area of the maximum signal can be made smaller than the beam width antenna itself could provide, leading to much improved accuracy. Würzburg D's accuracy was on the order of 2 degrees in azimuth and 3 degrees in elevation. In-service units were generally upgraded to the D model in the field.
Even the D model was not accurate enough for direct laying of guns. In order to provide the system with much greater accuracy, the FuMG 65 Würzburg-Riese ("Giant Würzburg") was developed. Based on the same basic circuitry as the D model, the new version featured a much larger 7.4 m antenna and a more powerful transmitter with a range of up to 70 kilometres (43.5 mi). Azimuth accuracy was 0.2 degrees and elevation 0.1 degree, more than enough for direct gun-laying. The system was now too large to be carried on a truck trailer, and was instead adapted for operation from a railway carriage as the Würzburg-Riese-E, of which 1,500 were produced during the war. The Würzburg-Riese Gigant was a very large version with a 160 kW transmitter, which never entered production.
A Würzburg system at Bruneval on the coast of France was captured by British Paratroopers
in Operation Biting
, while Operation Bellicose
bombed the suspected Würzburg radar factory. However, the Operation Hydra
bombing of Peenemünde
did not affect the nearby Giant Würzburg at the Lubmin
guidance and control station used for V-2 rocket
.
Gun laying
Gun laying is the process of aiming an artillery piece, such as a gun, howitzer or mortar on land or at sea against surface or air targets. It may be laying for direct fire, where the gun is aimed similarly to a rifle, or indirect fire, where firing data is calculated and applied to the sights...
radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
for both the Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
and the German Army
Wehrmacht
The Wehrmacht – from , to defend and , the might/power) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the Heer , the Kriegsmarine and the Luftwaffe .-Origin and use of the term:...
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. Initial development took place before the war, entering service in 1940. Eventually over 4,000 Würzburgs of various models were produced. It took its name from the city of Würzburg
Würzburg
Würzburg is a city in the region of Franconia which lies in the northern tip of Bavaria, Germany. Located at the Main River, it is the capital of the Regierungsbezirk Lower Franconia. The regional dialect is Franconian....
as the project leader liked geographical names.
Development
In January 1934 TelefunkenTelefunken
Telefunken is a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft...
met with German radar researchers, notably Dr. Rudolf Kühnhold
Rudolf Kühnhold
Rudolf Kühnhold was an experimental physicist who is often given credit for initiating research that led to the Funkmessgerät in Germany.-Early life:...
of the Communications Research Institute of the German Navy
German Navy
The German Navy is the navy of Germany and is part of the unified Bundeswehr .The German Navy traces its roots back to the Imperial Fleet of the revolutionary era of 1848 – 52 and more directly to the Prussian Navy, which later evolved into the Northern German Federal Navy...
and Dr. Hans Hollmann
Hans Hollmann
Hans Erich Hollmann was a German electronic specialist who made several breakthroughs in the development of radar....
, an expert in microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
s, who informed them of their work on an early warning radar
Early warning radar
An early warning radar is any radar system used primarily for the long-range detection of its targets, i.e., allowing defences to be alerted as early as possible before the intruder reaches its target, giving the defences the maximum time in which to operate...
. Telefunken's director of research, Dr. Wilhelm Runge
Wilhelm Runge
Wilhelm Tolmé Runge was an electrical engineer and physicist who had a major involvement in developing radar systems in Germany.-Early life:...
, was unimpressed, and dismissed the idea as science fiction
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
. The developers then went their own way and formed GEMA, eventually collaborating with Lorenz on the development of the Freya
Freya radar
Freya was an early warning radar deployed by Germany during World War II, 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 Seetakt...
and Seetakt
Seetakt radar
The shipborne Seetakt radar was developed in the 1930s and was used by the German Navy during World War II.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...
systems.
By the spring of 1935 GEMA's successes made it clear to Runge that the idea was workable after all, so he immediately started a crash program at Telefunken to develop radar systems of their own. With Lorenz already making progress on the early warning front, Runge had the Telefunken team concentrate on a short-range gun laying system instead. Management apparently felt it to be as uninteresting as Runge had a year earlier, and assigned it a low priority for development. Nevertheless, development started and by the summer they had built a working experimental unit working in the 50 cm band that was able to generate strong returns off a target Junkers Ju 52
Junkers Ju 52
The Junkers Ju 52 was a German transport aircraft manufactured from 1932 to 1945. It saw both civilian and military service during the 1930s and 1940s. In a civilian role, it flew with over 12 air carriers including Swissair and Deutsche Luft Hansa as an airliner and freight hauler...
. By the next summer, the experimental setup had been developed into a real prototype machine known as the Darmstadt, which offered a range accuracy of 50 m at 5 km, not nearly enough for gun laying. Attitudes changed in late 1938, when a full development contract was received from the Luftwaffe.
The resulting system, known as the FuMG 62, as well as the prototype system FuMG 39T Darmstadt were demonstrated to Hitler at Rechlin
Rechlin-Lärz Airfield
Rechlin-Lärz Airfield is an airfield in the village of Rechlin, Mecklenburg-Western Pomerania, Germany, which is certified for aviation equipment up to 14 tons weight...
in July 1939. The Telefunken team developed an accurate system based on a klystron
Klystron
A klystron is a specialized linear-beam vacuum tube . Klystrons are used as amplifiers at microwave and radio frequencies to produce both low-power reference signals for superheterodyne radar receivers and to produce high-power carrier waves for communications and the driving force for modern...
microwave
Microwave
Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...
tube operating in the range of 54 to 53 cm (553 to 566 MHz) – an extremely short wavelength for the time – with a pulse length of 2 microseconds, a peak power of 7 to 11 kW, and a PRF
Pulse repetition frequency
Pulse repetition frequency or Pulse repetition rate is the number of pulses per time unit . It is a measure or specification mostly used within various technical disciplines Pulse repetition frequency (PRF) or Pulse repetition rate (PRR) is the number of pulses per time unit (e.g. Seconds). It...
of 3,750 Hz. It had a maximum range of about 29 kilometres (18 mi), and was accurate to about 25 m in range. Würzburg used a 3 m paraboloid
Paraboloid
In mathematics, a paraboloid is a quadric surface of special kind. There are two kinds of paraboloids: elliptic and hyperbolic. The elliptic paraboloid is shaped like an oval cup and can have a maximum or minimum point....
dish antenna mounted on a wheeled trailer, and the dish could be "folded" along the horizontal midline for travel. The system was first accepted into service in 1940, and eventually 4,000 of this basic layout were delivered.
Several versions of the basic Würzburg system were deployed over the course of the war. The first, Würzburg A, was operated manually and required the operators to pinpoint the target by maintaining a maximum signal on their oscilloscope
Oscilloscope
An oscilloscope is a type of electronic test instrument that allows observation of constantly varying signal voltages, usually as a two-dimensional graph of one or more electrical potential differences using the vertical or 'Y' axis, plotted as a function of time,...
display. Since the signal strength changed on its own for various reasons as well as being on or off target, this was not very accurate, and generally required the use of a searchlight
Searchlight
A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...
to spot the target once the radar had settled on an approximate position. Nevertheless one of the very first Würzburgs claimed a plane in May 1940 by orally relaying commands to a flak unit. An experimental Würzburg B added an infra-red detector for "fine tuning", but in general these devices proved to be unusable and production was discontinued.
Lobe switching
Lobe switching is a method used on early radar sets to improve tracking accuracy. It used two slightly separated antenna elements to send the beam slightly to either side of the midline of the antenna, switching between the two to find which one gave the stronger return, thereby indicating which...
to improve aiming accuracy. The C model was aimed by sending the signal out of one of two slightly off-centre feed horns in the middle of the antenna, the signal being switched rapidly between the two horns. Both returns were sent to an oscilloscope display, slightly delaying the signal from one of the horns. The result appeared as two closely separated "spikes" which the operator attempted to keep at the same height on the display. This system offered much faster feedback on changes in target position, and since any change in signal strength would affect both lobes equally, the operator no longer had to "hunt" for the maximum signal point. An almost identical system was used in the United States' first gun-laying radar, the SCR-268
SCR-268 radar
The SCR-268 was the US Army's first radar system. It was developed to provide accurate aiming information and used in gun laying systems and directing searchlights against aircraft....
.
Conical scanning
Conical scanning is a system used in early radar units to improve their accuracy, as well as making it easier to steer the antenna properly to point at a target...
system, using an offset receiver feed called a "Quirl" (German for whisk
Whisk
A whisk is a cooking utensil used in food preparation to blend ingredients smooth, or to incorporate air into a mixture, in a process known as whisking or whipping. Most whisks consist of a long, narrow handle with a series of wire loops joined at the end. The wires are usually metal, but some are...
) that spun at 25 Hz. The resulting signal was slightly offset from the centreline of the dish, rotating around the axis and overlapping it in the centre. If the target aircraft was to one side of the antenna's axis, the system would see the strength of the signal grow and fade as the beam swept across it, allowing the system to move the dish in the direction of the maximum signal and thereby track the target. Additionally, the area of the maximum signal can be made smaller than the beam width antenna itself could provide, leading to much improved accuracy. Würzburg D's accuracy was on the order of 2 degrees in azimuth and 3 degrees in elevation. In-service units were generally upgraded to the D model in the field.
Even the D model was not accurate enough for direct laying of guns. In order to provide the system with much greater accuracy, the FuMG 65 Würzburg-Riese ("Giant Würzburg") was developed. Based on the same basic circuitry as the D model, the new version featured a much larger 7.4 m antenna and a more powerful transmitter with a range of up to 70 kilometres (43.5 mi). Azimuth accuracy was 0.2 degrees and elevation 0.1 degree, more than enough for direct gun-laying. The system was now too large to be carried on a truck trailer, and was instead adapted for operation from a railway carriage as the Würzburg-Riese-E, of which 1,500 were produced during the war. The Würzburg-Riese Gigant was a very large version with a 160 kW transmitter, which never entered production.
A Würzburg system at Bruneval on the coast of France was captured by British Paratroopers
British Commandos
The British Commandos were formed during the Second World War in June 1940, following a request from the British Prime Minister, Winston Churchill, for a force that could carry out raids against German-occupied Europe...
in Operation Biting
Operation Biting
Operation Biting, also known as the Bruneval Raid, was the codename given to a British Combined Operations raid on a German radar installation in Bruneval, France that occurred between 27–28 February 1942 during World War II...
, while Operation Bellicose
Operation Bellicose
The Operation Bellicose strategic bombing in World War II targeted the Nazi Germany Zeppelin Works in Friedrichshafen and the La Spezia, Italy, naval base and was the first use of shuttle bombing in World War II and the second use of a Master Bomber...
bombed the suspected Würzburg radar factory. However, the Operation Hydra
Bombing of Peenemünde in World War II
Operation Hydra was a Royal Air Force attack on the Peenemünde Army Research Center on the night of 17/18 August 1943. It began the Operation Crossbow strategic bombing campaign against Nazi Germany's V-weapon programme...
bombing of Peenemünde
Peenemünde
The Peenemünde Army Research Center was founded in 1937 as one of five military proving grounds under the Army Weapons Office ....
did not affect the nearby Giant Würzburg at the Lubmin
Lubmin
Lubmin is a coastal resort in the German state of Mecklenburg-Vorpommern. Lubmin is situated near Greifswald and on the Bay of Greifswald.Apart from tourism, Lubmin is a major transport and industry hub and investment location in the German energy sector...
guidance and control station used for V-2 rocket
V-2 rocket
The V-2 rocket , technical name Aggregat-4 , was a ballistic missile that was developed at the beginning of the Second World War in Germany, specifically targeted at London and later Antwerp. The liquid-propellant rocket was the world's first long-range combat-ballistic missile and first known...
.
See also
- List of World War II electronic warfare equipment
- German night fighter direction vessel TogoGerman night fighter direction vessel TogoLaunched in 1938, the MS Togo was a German merchant ship. At the outbreak of World War II in early September 1939, she was in the French port of Douala in Africa, but avoiding internment and running the Allied blockade, she successfully returned to Hamburg...
- RADARRadarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
External links
- ORIGINS OF GERMAN RADAR: SEETAKT, FREYA, WUERZBURG. There is an open source verification for this text on the home page Greg Goebel / In The Public Domain.
- Radar Development in Germany on the Radar World website
- The Radar War (PDF) by Gehard Hepcke, translated into English By Hannah Liebmann on the Radar World website
- MUSEUM "WAALSDORP" - Radio Communication with an antenna built during World-War II
- A captured Würzburg radar unit is used to develop WW2 countermeasures.