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The Development of German Radar in WW2 World Naval Ships Forums Archive


The Development of German Radar in WW2


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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B] [I](Part 1)[/I] [U]Introduction[/U][/B] Although this article is primarily about German radar, it should be remembered that similar developments were taking place simultaneously in other countries, particularly (but not exclusively) the United States and Britain. No one country could claim the credit for inventing radar, as at various times one was in advance of the others in some aspect or another. [U][B]Beginnings[/B][/U] The origin of radar is rooted in the history of radio development in general, which really began with the physicist James Clerk Maxwell publishing "[I]A Dynamical Theory of the Electromagnetic Field[/I]" in 1865. Maxwell theorised that electric and magnetic fields travel through space as waves moving at the speed of light, and that light was another form of the electromagnetic wave. Heinrich Hertz applied Maxwell's theories and proved in 1887 that such waves did indeed exist, and demonstrated that the speed of these waves was equal to the speed of light; proving that they were a form of light. His name was given to the basic unit of frequency of electromagnetic waves – the Hertz. In 1895, Marconi obtained a British patent for his wireless design, and by 1898, wireless stations were transmitting across the English Channel. While Hertz was experimenting with radio waves, he noted that surrounding objects interfered with the reception of these waves. By the turn of the century, this interference was well enough known for scientists to theorize how to use it. In 1900, Nikola Tesla suggested a wireless system which would use reflected radio waves to locate objects and even to measure their distance. ".[I] . . we may produce at will, from a sending station, an electrical effect in any particular region of the globe; we may determine the relative position or course of a moving object, such as a vessel at sea, the distance traversed by the same, or its speed[/I]." Tesla explained the concept as: “[I]When we raise the voice and hear an echo in reply, we know that the sound of the voice must have reached a distant wall or boundary, and must have been reflected from the same. Exactly as the sound, so an electrical wave is reflected, and the same evidence can be used to determine the relative position or course of a moving object such as a vessel at sea.[/I]” Thus the knowledge and theoretical basis for the building of radar existed at the turn of the century, and only needed someone with the imagination and resources to develop and build it. In 1904 a German inventor, Christian Hülsmeyer, was granted a patent for his 'telemobiloscope', which was a “[I]hertzian-wave projecting and receiving apparatus to give warning of the presence of a metallic body such as a ship or a train[/I].” In May 1904 he successfully demonstrated his “anti ship colliding system”, proving that a ship fitted with such a transmitter and receiver could detect the presence of another ship up to 5 kilometres away. He had an idea of mounting the assembly on the foremast of a ship to measure the range and bearing of an object. But no one was interested, so he abandoned his development work to pursue other more lucrative fields. [CENTER]-----“----- [/CENTER] [B][U]Radar principles [/U][/B](simplified) Radar uses the effect that radio waves, like sound waves, are reflected from objects in their path, just as Tesla explained. To know from which direction the reflection is received, and thus the direction of the object, the radio wave is directed into a narrow beam by the transmit antenna, so that if a return signal is received, then the object must lay in the direction in which the beam was transmitted. Usually, the stronger the return signal, the larger the object for a given distance. In order to know how far away the object is, the radio wave is transmitted as a series of short pulses, and the time taken from the moment of transmission to reception is measured. As it is known that radio waves travel at the speed of light (186,000 miles/sec, or 300,000 km/sec) the distance of the object can be simply calculated. For example, if the signal takes one millisecond to return, it has travelled 300 km there and back; therefore the object must be 150 km away. If a series of returns are plotted, the course and speed of the object can be determined. To measure the distance (that is the time taken to receive the return signal) an oscilloscope was used to display the received signals. The line displayed on the oscilloscope is called the trace, which can be horizontal, vertical of circular. The trace is synchronised with, and started by, the transmitted pulse and continues moving, displaying any returned signal. The distance from the start of the trace to the returned signal represents the distance of the object; and as the screen was usually marked with a calibrated graticule, the distance of the object could be read off directly. An estimate of the size of the object could be made by the amplitude and width of the return signal; so if the object was a group of aircraft, their numbers could be estimated. Radio energy is absorbed by the atmosphere, and the further a radio wave travels the weaker it gets. This attenuation is greater for shorter wavelengths than for longer wavelengths. Therefore to detect objects at long distance, enormous transmission power is required - 100s of kW; even then small objects like a single aircraft can escape detection. Shorter wavelengths enable single aircraft to be detected, and more detail to be seen from the return signal. A squadron of aircraft which may appear as a single large object at long wavelengths will be seen as individual aircraft if the wavelength is short enough. In the 1930’s, there was simply no means of generating short wavelengths with enough power to detect objects at any great distance. Consequently, long wavelength radar (1 to 15 metres) was used to detect objects at long distance, and short wavelength radar (less than 1 metre) for the shorter distances. [CENTER]-----“----- [/CENTER] [U][B]Technical stuff[/B][/U] (simplified) Without wishing to bog this article down in technical jargon, a basic definition of the terms used in connection with radio and radar signals follows. [I][B]Frequency and Wavelength[/B][/I] The frequency of a radio signal is the number of oscillations it makes in one second, and is measured in Hertz. The wavelength is the length of one complete oscillation, and is measured in metres. Because radio waves travel at the speed of light (300,000,000 metres/second), there is a simple relationship between wavelength and frequency: [I]Wavelength (in meters) = 300 divided by the Frequency (in Megahertz).[/I] Thus, higher the frequency, the shorter the wavelength; e.g: a frequency of 300 MHz (300,000,000 Hz) will have a wavelength of 1 metre, and a frequency of 600 MHz will have a wavelength of 50cm. [U][B]The frequency spectrum[/B][/U] [U]High frequency[/U] (HF) The range of frequencies from 3 to 30 MHz, (wavelengths = 100 metres down to 10 metres) Radar example: Chain Home (British) [U]Very high frequency[/U] (VHF) The range of frequencies from 30 to 300 MHz, (wavelengths = 10 metres down to 1 metre) Radar example: Freya (German) [U]Ultra high frequency[/U] (UHF) The range of frequencies from 300 to 3,000 MHz (wavelengths = 1 metre down to 10 cm) Radar example: Wurzburg and Lichtenstein (German) [U]Super high frequency[/U] (SHF) The range of frequencies from 3,000 - 30,000 MHz, or 3 to 30 GHz, (wavelengths = 10 cm down to 1 centimetre) Radar example: H2S and ASV3 (British) These ranges of frequency are sometimes described by their wavelengths; whereby VHF = metric wavelengths; UHF = decimetric; and SHF = centimetric. [I][B]Microwave[/B][/I] This is a non specific term, and refers to wavelengths of less than one metre, thus encompassing the whole UHF, SHF spectrum and beyond (EHF), with wavelengths from one metre down to one millimetre. [I][B]Pulse recurrence frequency[/B][/I] (PRF) This is the number of radar pulses transmitted per second; sometimes called the pulse repetition rate (PRR). The PRF depends on the designed maximum range of the radar, as time has to be allowed for the echo from one pulse to be received from maximum range before the next one is transmitted. In general, long range radar operates at low frequencies (HF and VHF) with a low PRF, while shorter range radar operates at high frequencies (UHF and SHF) with a high PRF. [I][B]Antennae, dipoles and polarisation[/B][/I] An antenna usually consists of a dipole or an array of dipoles. A dipole is simply a pair of conductors usually arranged along the same axis, with a connection to each conductor, either from the transmitter or to the receiver. The dipole is tuned by matching its physical length to the radar wavelength, and is usual a proportion of the wavelength; so we can have full wave, half wave, or quarter wave dipoles etc. If the radar wavelength is 2.4 metres, then a full wave dipole has two elements, each of length 1.2 metres, making 2.4 metres. Several dipoles acting together and connected to the same equipment are called an antenna array. A single dipole will radiate radio waves in all directions, but multiple dipoles can be arranged in such a way as to radiate most of their energy in a single direction; such a signal is sometimes called a beam. Dipoles arranged vertically are said to be vertically polarised, and horizontal arrangements are horizontally polarised. The polarisation determines the shape of the radiated signal (beam). Vertical polarisation produces a wide and flattish beam, while horizontal polarisation produces a tall and narrow beam. [I][B]Range, azimuth and elevation[/B][/I] Range is the distance of the object from the receiver; azimuth is its bearing with respect to the receiver; and elevation is the angle it makes with the horizontal. The height of the target is calculated by multiplying the range by the Sine of the elevation angle. Most radars measure three factors to position a target; range, azimuth and elevation, but some measure only range and azimuth. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]


Very interesting Bill, and thanks for keeping it simple. Jim


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B] [I](Part 2)[/I] [U]Scope[/U][/B] This series of articles will cover the development of the main types of German radar used in WW2. It will be of a general nature and will not be a detailed list of the variants of each type – they are simply too numerous – although the more interesting variants are mentioned. Also, the information available for some models is so sparse that little more is known of them other than their codename. The model numbers of German radars are confusing, and it is impossible to obtain a complete and accurate list of them. The common designation is usually prefixed FuMG, which simply means Radio Measuring Apparatus, but sometimes it is DeTe, FuSE, FMG, FuMO, etc., depending on when and whether it was in service with the Luftwaffe or the Kriegsmarine – but not always! To add to the confusion, in 1943 all designations were replaced by a standardised system, including those already in service. Thus if a radar type was in use by the Luftwaffe and Kriegsmarine before 1943 it is possible that it could have three or four different designations! To minimise confusion, I have simply called the different models by their codenames (Freya, Wurzburg etc.) and noting their post 1943 designated numbers where known. The land based radars will be dealt with first; airborne and naval radars will come later. The land based radars were to detect enemy aircraft, and were operated mainly by the Luftwaffe, with some coastal stations operated by the Kriegsmarine to detect both ships and aircraft. [CENTER]-----“----- [/CENTER] [U][B]Pre-war developments[/B][/U] In the early 1930s, Dr. Rudolph Kühnold, head of the German Navy’s signals research, was working on the detection of underwater objects by sonar, when it occurred to him that the same principles could be applied above water to detect ships with radio waves. In 1933, unaware of Hülsmeyer’s earlier work of 1904, he succeeded in producing an apparatus to prove his theory. Later that year, he demonstrated it by detecting ships over 10km away. He then approached Telefunken with a view to it cooperating in its development, but they weren’t interested. So Kuhnhold, with a few acquaintances who together had been interested for several years in high frequency radio techniques, founded the GEMA company (Gesellschaft für Elektroakustische und Mechanische Apparate) to develop his apparatus. [U][I][B]GEMA[/B][/I][/U] The Kriegsmarine had been impressed by Kuhnhold’s experimental radar and granted development funds to GEMA, which began development in January 1934. A few months later, GEMA demonstrated a working version in Kiel harbour. After further development, in the autumn of 1934 they had a system operating on a 50 cm wavelength (600 MHz) which could detect ships up to 10km away. But again, it was still only a Hülsmeyer continuous wave interference detection radar giving an indication of the presence of a ship with a rough bearing but no range. Dr. Hans Hollman had studied microwaves, cathode ray tubes, the ionosphere and radio astronomy at the Heinrich Hertz Institute for Oscillatory Research in Berlin. For his work on the ionosphere in the late 1920s, he had developed and built a decimetric transmitter and receiver with pulsed modulation to measure the height above Earth of this layer. In 1934 he became a consultant to GEMA, and in 1935 his technique of using pulsed transmissions improved GEMA’s experimental radar, enabling it to measure range and azimuth quite accurately. The prototype was demonstrated to Admiral Raeder later that year. [[B]Note:[/B] In 1935, Hollman published a book entitled “[I]Physics and Techniques of Ultrashort Waves[/I]”, which was picked up by researchers around the world. In the same year he developed and patented a cavity magnetron.] GEMA rapidly improved the prototype by optimising the frequency used which extended its range and accuracy. These improvements gave the new radar the ability to spot aircraft as well as ships. It could detect a light cruiser, 8 km away, with an accuracy of up to 50 m, enough for gun-laying. The same system could also detect an aircraft at 500m altitude at a distance of 28 km. The military implications were obvious and GEMA went on to develop the technology into two separate applications: a land based version for aircraft detection called Freya, and a shorter wavelength naval version called Seetakt. At the outbreak of WW2, Germany had eight Freya stations covering its coastline between Holland and Denmark. Meanwhile, the success of GEMA had been noted by Germany's two largest electronics companies, Telefunken and Lorenz. [U][I][B]Telefunken[/B][/I][/U] Telefunken had been working with Hans Hollman since about 1930 developing a UHF communications system. After rejecting Kuhnold’s approach in 1933, they finally became interested in radar only after GEMA had been given substantial military contracts. In 1936, using the advanced technology of their UHF communications system, they began developing a small mobile radar they called “Darmstadt”. It could measure range, azimuth and elevation, and had the ability to plot aircraft up to ranges of 25 miles, and was accurate enough to be used as an AA gun laying radar. This was further developed and put into production and called “Wurzburg”. [[B]Note:[/B] All Telefunken radars were named after German cities.] [U][I][B]Lorenz[/B][/I][/U] Lorenz had built an experimental 70cm pulsed radar by the beginning of 1936. It worked, but had a limited range; so to improve it the wavelength was changed to 62.5cm and the ‘mattress’ antenna replaced by an antenna with parabolic reflectors. These improvements increased its range against aircraft to 30km. Lorenz called this radar ‘Kurfurst’. When, in 1938, there was competition for the development of gun laying radar for antiaircraft artillery, Lorenz submitted their Kurfurst radar and Telefunken their Wurzburg radar. The Würzburg from Telefunken was preferred, so Lorenz abandoned the Kurfurst and went on to develop the Kurpfalz and the Kurmark to succeed it. [[B]Note:[/B] Prior to 1939, Lorenz and Telefunken were Germany’s leading electronics research companies. Lorenz was a subsidiary of the American IT & T company, and filed its patents in the USA. It is probably for reasons of security, that the German government was reluctant to place orders for advanced equipment with Lorenz. Thus the preference for Telefunken’s Wurzburg may have been as much a political decision as a technical one. It wasn’t until 1942/43 that Lorenz became significantly engaged in radar work, but was excluded from centimetric radar technology.] [U]Kurfurst[/U] (FuMG 38 L) The Kurfürst had two 2.4 meter diameter parabolic reflectors, one each for transmit and receive. These were attached to a hollow mast which was fitted, in place of the barrel, to the base of an 88mm Flak gun. It operated on a wavelength of 62.4 cm and had a range of 8-12 km, with an accuracy of ±100 metres, and elevation accuracy of ±3-4 degrees. [U]Kurpfalz[/U] (FuMG 39 L) The Kurpfalz was a follow-on development of the Kurfürst with a more powerful transmitter and improved accuracy. The antenna, consisting of two wire mesh parabolic dishes of diameter 2.4 meters attached to the roof of an operations van. The antenna could be folded down onto its roof for transport. The system’s range was about 10-25 km, with an accuracy of ±40-50 metres; accuracy was ±2-3° for azimuth and ±3-4° for elevation. [U]Kurmark[/U] (FuMG 40 L) Externally the Kurmark differed little from the Kurpfalz. Transmission power was increased, giving it a range of 25-40 km, with an accuracy of ±30-40 metres. Azimuth and elevation accuracy was about ±0.7 degrees. The Kurmark was the last radar system built by Lorenz for deployment with Flak units. [U]Attachments[/U]: 1. GEMA Freya with no IFF. 2. Telefunken Wurzburg with IFF. 3. Lorenz Kurfurst mounted on an 88mm Flak gun with its barrel replaced by a rotatable tube. 4. Lorenz Kurpfalz and its operations van. [ATTACH]137442[/ATTACH] [ATTACH]137443[/ATTACH] [ATTACH]137444[/ATTACH] [ATTACH]137446[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
Attachments :


Attachment 1


Attachment 2


Attachment 3


Attachment 4



Interesting read. [QUOTE]Radio energy is absorbed by the atmosphere, and the further a radio wave travels the weaker it gets.[/QUOTE] Isn't this due to a (modified) inverse square law ? No antenna 'beam' can be infinitely narrow, so the same amount of energy is spread over an increasingly wider wavefront. Any reflected signal will suffer the same weakening when received back at the originating location, thus compounding the effect. [QUOTE]This attenuation is greater for shorter wavelengths than for longer wavelengths[/QUOTE] Does 'Ground Wave' propagation have any relevance at these frequencies ? Most people will have noticed that (in daylight) broadcast stations on Long Wave can be received at greater distances than Medium Wave (& even within MW signals around 600 kHz much better than 1,500 kHz) Pete


[quote=peteR09;10090780]Isn't this due to a (modified) inverse square law ? No antenna 'beam' can be infinitely narrow, so the same amount of energy is spread over an increasingly wider wavefront. Any reflected signal will suffer the same weakening when received back at the originating location, thus compounding the effect.[/quote] That is partly correct; the inverse square law is applicable to an unguided radio signal transmitted evenly in all directions, but doesn't apply to a 'beamed' signal where the energy is mainly directed in one direction. If it were possible for a beam to be perfectly parallel like a laser beam, the energy loss would be entirely by absorption. But with a diverging beam the overall attenuation is a combination of both spreading and absorption. [quote=peteR09;10090780]Does 'Ground Wave' propagation have any relevance at these frequencies? Most people will have noticed that (in daylight) broadcast stations on Long Wave can be received at greater distances than Medium Wave (& even within MW signals around 600 kHz much better than 1,500 kHz).[/quote] Certainly long waves (over 1,000 metres) can propagate long distances due to the ability of the ground wave to 'bend' around the Earth's curvature. The behaviour of medium waves (100 to 1,000 metres) depends on several factors, one of which is the time of day/night. These waves don't bend as much as longwaves. Daylight reception is mainly from the groundwave, because the skywave is mostly absorbed by the E-layer (I think from memory). At night, the E-layer is greatly reduced, allowing the skywave to penetrate and be reflected back from the ionosphere, and thus reach further afield.


[quote=jbryce1437;10090712]Very interesting Bill, and thanks for keeping it simple. Jim[/quote] Thank you Jim, sorry for the time taken to acknowledge you, but I have only just noticed your reply.


[QUOTE=emason; [U]Scope[/U][/B] This series of articles will cover the development of the main types of German radar used in WW2. It will be of a general nature and will not be a detailed list of the variants of each type – they are simply too numerous – although the more interesting variants are mentioned. Also, the information available for some models is so sparse that little more is known of them other than their codename. Stellar posts! Whalecatcher


Appreciated, Whalecatcher.:)


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B] [I](Part 3)[/I][/B] [U][B]Freya early warning / search radar[/B][/U] (FuMG 39 G) Freya, named after the Norse deity, was developed by GEMA and was in service from 1938 to 1945. From the initial eight stations installed at the outbreak of WW2, another eleven Freya stations were installed along Germany's western border in early 1940. After the invasion of France, additional Freya stations were installed along the Channel and Atlantic coasts. When Britain started its bombing raids, many more Freya stations were deployed inland to strengthen the anti-aircraft defences. By the end of the war over a thousand stations were deployed. Freya’s primary purpose was the long range detection of enemy aircraft, but despite this role, it could provide only the range and azimuth, but not the altitude of approaching aircraft. The range of the target was read off a CRT, but the operator had to manually rotate the whole antenna array to obtain the strongest signal to determine the azimuth. Freya supported a version of IFF in which aircraft equipped with the GEMA IFF ‘Erstling’ could be successfully queried across ranges of over 100 km. Freya was often used together with the gun laying radar Würzburg; with incoming aircraft detected initially with Freya, and when within range, passing them on to the shorter range Würzburg which could determine altitude. Up until early 1941, Freya operated on a wavelength of 2.5 metres (120 MHz) with a pulse recurrence frequency of 1000, and had a range of about 80 Km. When it was found that aircraft at high altitude could be detected well beyond this range, the PRF was lowered to 500, giving it a range of about 150 Km. [[B]Note:[/B] The detectable range is dependent on the height of an aircraft; the lower its altitude the shorter the range.] Initially, Freya operated on a single wavelength, but when jamming began in 1942, its operating range was extended so the operator could select a wavelength which wasn’t being jammed. [U][B]Characteristics[/B][/U] Each model of the Freya was slightly different, but generally: Frequency: 120-150 MHz (2.5 to 2.0 m); later extended to 82-190 (3.6 to 1.6 m). Pulse peak power: 15-20 kW. PRF: initially 1,000 Hz; later 500 Hz. Pulse duration: 2-3 microseconds. Range: 80-150 Km dependent on height of target. [CENTER]-----“----- [/CENTER] [U][B]Developments[/B][/U] The Luftwaffe had its signals research organisation based at Kothen, Germany. This was called the Luftnachrichtung Versuchs Regiment, which was usually referred to simply as Köthen (just as the GCCS is now referred to as Bletchley). Its Director was Dr. Rudolf Kuhnold. It played a prominent role in the specification, development and modification of radar systems, both new and old. [[B]Note:[/B] Not all of the following models were manufactured by GEMA – they hadn’t the capacity; so although designed and developed by GEMA, some of them were actually built by Lorenz, Telefunken and AEG.] [I][B] The Freya A/N [/B][/I] To improve the bearing (azimuth) measurement, GEMA developed "lobe switching" which enabled the transmitted signal (beam) to be radiated at a slightly different angles, switched alternately 75 times per second electronically. This enabled the operator to position the target in the narrow overlapping part of the beams to obtain a fine resolution of azimuth. With the Freya A/N, a skilled operator could obtain an azimuth accuracy of 0.1°. This was precise enough for night fighter interception, but doesn’t appear to have been used in this way. [U]Attachment[/U]: 1. Freya A/N [ATTACH]137492[/ATTACH] [CENTER]-----“----- [/CENTER] [I][B]The Freya LZ [/B][/I] This was developed in cooperation with the Zeppelin company, and was specially designed to be transportable by aircraft. It was the culmination of all GEMA’s previous development work and was regarded as their finest radar. [U]Attachment[/U]: 1. Freya LZ (FuMG 541) [ATTACH]137493[/ATTACH] [CENTER]-----“----- [/CENTER] [I][B]The Freya-Fahrstuhl [/B][/I] Freya's greatest deficiency was its inability to determine the altitude of approaching aircraft. To overcome this, Köthen designed the 'Freya-Fahrstuhl' which was a 40ft tall wooden frame in which a Freya antenna array was fitted so it could slide up and down like a giant guillotine. This enabled Freya to provide an estimate of the target's altitude by measuring the phase difference between the direct return signal and the reflected ground wave. The extra height also gave it a longer range for low flying aircraft. This model used a wavelength of 2.0 metres and had a range of 220 km. In later models, the wooden frame was replaced by a taller 60ft metal pylon. From its first installation in early 1943, it was never fully satisfactory, and only about eight were deployed, which nevertheless remained in operation until 1945. These were mainly used to give the target’s altitude to the Flak batteries when the Würzburgs were being jammed. [U]Attachments[/U]: 1. Early Freya-Fahrstuhl with wooden frame. 2. Later model with metal pylon. [ATTACH]137494[/ATTACH] [ATTACH]137495[/ATTACH] [CENTER]-----“----- [/CENTER] [I][B]The Freya Freiburg [/B][/I] This was a land based naval radar used for ‘coastwatching’. [U]Attachment[/U]: 1. Freya Freiburg. [ATTACH]137496[/ATTACH] [CENTER]-----“----- [/CENTER] [I][B]The Dreh-Freya [/B][/I] This was also known as the Freya Panorama, and was first introduced in June 1944. It consisted of a Freya LZ antenna working at 1.90-2.50 metres, which rotated through 360°. Received signals were displayed on a Plan Position Indicator (PPI). About 20 units were in use in January 1945. The range claimed for it was only about 100 km. Further development and manufacture was handed over to Lorenz. The Dreh-Freya can easily be recognised as it was the only Freya whose antenna were mounted horizontally (horizontally polarised). [U]Attachment[/U]: 1. Dreh-Freya [ATTACH]137497[/ATTACH] [CENTER]-----“----- [/CENTER] [B][I]The Freya Verbunkert [/I][/B] This was another panorama radar with a PPI and a rotating antenna. The antenna was separated from the operator's cabin, which was now located in a sunken bunker to protect the operators from air attack. This was probably no more than a Dreh-Freya with the control cabin separated from the antenna and placed underground. [U]Attachment[/U]: 1. Freya verbunkert. [ATTACH]137498[/ATTACH] [CENTER]-----“----- [/CENTER] [I][B] The Freya Kothen [/B][/I] This was a long wavelength (3.4 metres) version, developed by Kothen, to avoid jamming. It was equipped with Yagi receiving antennae. Köthen had found that getting Freya to work satisfactorily with wavelengths of over 4 metres was problematic. This was overcome by mounting Yagi receiving antenna above the normal transmitting antenna. In early 1945 experiments were also being made with a Köthen Freya on about 12 metres wavelength. It is not thought that either of these models made it into production. To prevent these longer wavelengths being compromised, a device was built into these Freyas which allowed transmission of only ten pulses at a time, and prevented any more for between 2 and 22 seconds. It was thought unlikely that monitoring aircraft could tune into these short transmission. [U]Attachment[/U]: 1. Freya Kothen with Yagi. [ATTACH]137499[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B] Special Purpose Freyas[/B][/U] The Freya was used in a number of roles: early warning, night fighter control and navigation, for which they were specially adapted, of which two are described here. [I][B]The Freya Flamme [/B][/I] This was developed to counteract the effects of jamming, and worked by interrogating the IFF of British aircraft, so the bomber stream could still be followed as the IFF return signals could still be seen and heard through the jamming. Some RAF aircrew were reluctant to switch off their IFF, as they believed it prevented radar guided searchlights from locating them. Not only was this nonsense, it was also against orders; and it only needed one IFF left on for the whole bomber stream to be detected and tracked, irrespective of jamming. Initially Freya Flamme was a useful very long range early warning. It was claimed that with high flying aircraft, ranges of up to 450 km could be obtained. But as the war progressed, and the value of unnecessary emissions to the enemy was realised, the usefulness of Freya Flamme greatly diminished. A Freya Flamme antenna array can easily be recognised, as it is has eight dipoles in each row instead of the normal six. Strictly speaking, this wasn’t a radar in the usual sense. [U]Attachment[/U]: 1. Freya Flamme. [ATTACH]137500[/ATTACH] [I][B]Freya EGON[/B][/I] This Freya wasn't really a radar either, but the main component in the EGON (Erstling-Gemse-Offensiv-Navigation) long range navigation system that was used to guide bombers initially, then later for night fighter control in 1943. It was a modified Freya LZ with the transmit and IFF antenna, but without the receive antenna. Its main purpose was to trigger the aircraft's IFF (Erstling) at ranges up to 250km, whose signal was then used by other equipment to fix accurately the aircraft’s position. Like the Freya Flamme, it also had eight dipoles in each row. [U]Attachment[/U]: 1. Freya EGON, with Giant Wurzburg. [ATTACH]137501[/ATTACH] [CENTER]-----"----- [/CENTER] [U][B]The Freya in operation[/B][/U] [B]1)[/B] Freya was first used successfully on 18 December 1939 when a daytime raid by 24 Wellington bombers of No.3 Group, targeting the [I]Scharnhorst[/I] and [I]Geisnau[/I] in Wilhelmshafen, was detected while crossing the Heligoland Bight at a range of 110 km by the Freya station on Wangerooge (the easternmost of the East Friesan Islands), which alerted the coastal defences and the Luftwaffe. Fighter planes were guided towards them via radio, and twelve were shot down. [B]2)[/B] On 29 July 1940, after leaving Portland Harbour in daylight, the destroyer [I]HMS Delight[/I] was detected by the Freya station at Auderville, France at a range of 60 Miles. The Luftwaffe were alerted and 16 aircraft attacked and sank her about 20 miles off Portland Bill. [U][B]Discovery[/B][/U] The “Oslo Report” was an anonymously written document, received at the British Embassy in Oslo in November 1939. It described in some detail, technical advances in a wide range of military equipment made by the Germans. A part of it relates to radar: “[I]At the time of the attack by English airmen on Wilhelmshafen in early September, the English aircraft were already detected when they were still 120 Km off the German coast. Along the entire German coast 20 kW short-wave transmitters have been installed, which transmit very short pulses of 10 micro second duration. These pulses are reflected by the aircraft. . . . From the interval between the transmitted and the reflected pulses the distance of the aircraft can be calculated. . . . The transmitted pulse is displayed on the cathode-ray tube as a fixed mark. Such transmitters are to be installed throughout Germany by April 1940[/I]." This must refer to the Freya radar, as only they were engaged in this role in this area at this time. [[B]Note:[/B] There is more on the Oslo Report here: [URL]http://www.worldnavalships.com/forums/showthread.php?t=7197[/URL] ] The name ‘Freya’ had been mentioned in Enigma decrypts and was suspected of being a type of radar. The first indication of its existence was learned by the British in the summer of 1940 from an Enigma decrypt which reported, on 29 July 1940, that the Auderville Freya had detected [I]HMS Delight[/I] at a range of 60 miles and was sunk by Luftwaffe. But the best photographs of that area failed to show anything. It wasn’t until January 1941 that a routine low level flight by PRU aircraft produced a photograph of the Auderville peninsular (NW of Cherbourg), which showed some unusual structures. These were identified as radar antenna, confirming that Freya was indeed a radar. In February 1941, Freya transmissions were tuned into and measured, showing its characteristics of 120 MHz (2.5 metres) with a pulse repetition rate of 1,000. The bearing of the signal showed it originated from Auderville. Once the transmission characteristics were known, Freya stations along the coast were located and plotted, giving a picture of the German coastal defences. [U]Attachment[/U]: 1. The Freyas at Auderville. [ATTACH]137502[/ATTACH] [U][B]Countermeasures[/B][/U] Again from the “Oslo Report”: “[I]Countermeasures. By means of special receivers, which can register pulses lasting 1 to 10 micro seconds, the wave-lengths of the pulses transmitted in Germany must be determined and then interfering signals must be transmitted on the same wave-length. These receivers can be on the ground as well as the transmitters, since the method is very sensitive.[/I]” To counter Freya, the British used a ‘spoofing’ equipment called ‘Moonshine’, which retransmitted a portion of the Freya signal amplifying the return, simulating many aircraft. Carried by aircraft of the Special Duties Flight (later 515 Squadron, which became part of 100 Group), eight aircraft with Moonshine could mimic a force of 100 bombers. Another system ‘Mandrel’ was simply a noise generator which overwhelmed the Freya signals. Individual aircraft were sent to orbit fixed positions 50 miles (80 km) off the enemy coast. By using nine aircraft, a 200 section of the German's radar coverage could be severely degraded, while more ‘Mandrel’ were carried in the bomber stream to counter the inland Freya network. After this, much development work was undertaken by Kothen and the German radar companies to counteract jamming. Countermeasures at first involved providing several alternative wavelengths to which operators could change when jamming or spoofing occurred. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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A characteristcally well researched and excellently presented thread Bill. Always a pleasure to follow your contributions.


[quote=emason;10090710]Although this article is primarily about German radar, it should be remembered that similar developments were taking place simultaneously in other countries, particularly (but not exclusively) the United States and Britain. No one country could claim the credit for inventing radar, as at various times one was in advance of the others in some aspect or another. [/quote] Far from wanting to skew this thread away form the subject of German radar, could I just mention the contribution to radar development by Sir Robert Alexander Watson-Watt, and his work at Thames Ditton, Berkshire during the mid 1930's. Watt was awarded a patent in 1936 for a '[I]radio[/I] [I]device for detecting and locating an aircraft'[/I]. It was his work that gave birth to the radar stations being built on the east and south coast that made a vital contribution to the Battle of Britain. The site at Thames Ditton where Watt carried out his work, was the Radio Space Research Station, and somewhere where I had the privilege of "training" in the mid 1970's. I was aware then that I was working in a hallowed place in radar history, and have fond memories of my short time there. Sorry Bill, a little bit of self-indulgence - please continue with the German radar development.


[quote=Dreadnought;10090967]A characteristcally well researched and excellently presented thread Bill. Always a pleasure to follow your contributions.[/quote] Thank you Clive, very kind of you.


Thanks for the clarification to my earlier points, & the subsequent continuation of the article. I'm intrigued by the 2nd image in post #3 (the dish). Aren't dishes usually sized many wavelengths across? Depending on the scale of the trailer the central dipole & side elements (directors/reflectors?) look as if they are in the VHF range. However if you look closely there seems to be another small dipole just behind the larger one (perhaps using the main dipole as reflector to enhance the 'feed' ?) - which might make better use of the dish. Were these systems dual frequency? Pete Edit: Don't know if I can delete entire post, so am editing. I should have read post #3 properly - you did say it also had IFF. The outer antennas are apparently the IFF:- [url]http://lucafusari.altervista.org/page1/page26/WurzburgRadar.html[/url] P


Hello Pete, I don't know how much of your last post you wished to delete, but I will try and answer all your questions anyway. 1. The 3 metre reflector is approximately six times the wavelength of 53cm. 2. The two dipoles inside both edges of the reflector are for the IFF. The early Wurzburgs were built to accomodate the Telefunken built 'Zwilling' IFF set. This operated on the same wavelength as the Wurzburg but used a different PRF. I believe that later, the superior GEMA 'Erstling' IFF was adopted as it made no sense for aircraft to carry two different IFF systems to suit the radar interrogating them. 3. Both types of IFF received at the same wavelength as the radar but required a different PRF, and normally responded on a different wavelength. 4. The Wurzburg transmit antenna directed the signal back to the reflector to produce a focussed beam and make best use of the signal energy. 5. The early Wurzburgs, as all German early radar, were single frequency systems. When it was realised how susceptable they were to jamming, a range of frequencies within the same band was provided.


A fascinating thread Bill - many thanks for all your efforts. One question - was it a "Freya" installation which was one of the objectives of the ill-fated raid on Dieppe in 1942?


[CENTER][B][U]The Development of German Radar in WW2[/U][/B] [/CENTER] [B] [I](Part 4)[/I] [U]The Wurzburg[/U][/B] (FuMG 62) The Telefunken built Wurzburg was a small mobile radar unit with a three metre concave reflector. It was first deployed in mid 1940, and was used primarily as a fire control radar at Flak batteries to determine the height, range and bearing of enemy aircraft for searchlights and AA artillery. All Wurzburgs were equipped with IFF interrogation so that German aircraft would not be targeted. As usual, the performance of the radar was improved with later models, but the first models (Wurzburg A) used fixed wavelengths between 53.0 and 54.2 cm. The PRF was 3,750Hz which increased to 5,000Hz when the IFF was activated, during which time the radar was inoperative. The range was from 20 to 30 km, with an accuracy of 100m. Azimuth and elevation error was less than 2 degrees. To counteract the effect of jamming by ‘Window’, a device called Nurzburg was attached to the Wurzburg in September 1943. It used the Doppler effect to allow the radar to distinguish between the slow falling ‘Window’ and the high speed aircraft. This was replaced by the K-Laus signal processor by the summer of 1944. Over the course of the war, more than 4,000 Wurzburgs in all versions were deployed. [CENTER]-----“----- [/CENTER] [I][B]Wurzburg A[/B][/I] This was the first production model, introduced in 1940. The operator display consisted of three oscilloscopes, one each for range, azimuth and elevation. The radar required the operators to locate and follow the target manually by positioning the reflector to maintain a maximum signal on the oscilloscopes. Maintaining this maximum was at times difficult, since the signal strength varied naturally, as well as being on or off target. Consequently, accuracy suffered, but was usually good enough to direct a searchlight close enough to illuminate the target for the Flak. The IFF antenna was a pair of dipoles mounted inside the concave reflector. The operator activated the IFF by pressing a button, which increased the PRF to 5,000Hz, during which time the Wurzburg was ‘blind’. [U]Attachments[/U]: 1. Wurzburg A (see post #3, attachment 2). 2. Operator controls. [ATTACH]137551[/ATTACH] [CENTER]-----"----- [/CENTER] [I][B] Wurzburg B[/B][/I] The Würzburg B was an experimental model to which was coupled an infra-red telescope, but whose performance proved to be unsatisfactory and it wasn’t put into production. [[B]Note:[/B] The infra-red telescope codename ‘Spanner’, focussed on the heat of aircraft exhaust, but was only partially successful due to its short range and dependence on clear weather.] [CENTER]-----"----- [/CENTER] [I][B] Wurzburg C[/B][/I] This type, introduced in 1941, was a modification of the basic design with lobe switching added for improved accuracy. Instead of the usual stationary dipole at the focal point of the reflector, two dipoles slightly offset from the centre were rotated at 25 Hz. By rapid switching between the dipoles, two offset lobes were obtained. To follow the target, the operator maintained the two received signals at equal strength. This system was much easier and faster to operate, as any change in signal strength would affect both lobes equally, so the operator no longer had to "hunt" for the maximum signal point. Three oscilloscopes were used: one large one with a circular time base for range measurement, and two smaller ones for azimuth and elevation. The operator read off the range from the larger range display and set it into a circular scale which adjusted the azimuth and elevation displays to bring the target within their range for easier aiming and measurement. [U]Attachment[/U]: 1. Wurzburg C. [ATTACH]137552[/ATTACH] [CENTER]-----"----- [/CENTER] [B][I]Wurzburg D[/I][/B] The Würzburg model D, introduced in 1942, had still only a 40 km range, but was a general improvement over the model C. It was fitted with a fourth oscilloscope for precision range measurement. The model D had a single IFF antenna mounted on the cap of the rotating antennae at the focal point of the reflector instead of the normal two on each side. [U]Attachment[/U]: 1. Wurzburg D. [ATTACH]137553[/ATTACH] [CENTER]-----"----- [/CENTER] [I][B]Würzburg Riese[/B][/I] (FuMG 65 Giant Wurzburg) The Wurzburg D model was not accurate enough for direct gun laying, and its range too short for effective night fighter direction. To remedy these deficiencies, the Würzburg Riese was developed. Based on the D model, the new version featured a much larger 7.4 metre reflector and a more powerful transmitter with a range of up to 70 kilometres. Azimuth accuracy was 0.2 degrees and elevation 0.1 degree. The PRF was reduced from 3,750 Hz to 1,875 Hz to adjust to the longer range. In contrast to the solid metal reflector of the smaller Wurzburg, the Riese had a mesh covered lattice paraboloid structure built by the Zeppelin company, which resembled the nose cone of a airship. From the start, these Giants were used almost exclusively for night fighter direction. [U]Attachments[/U]: 1. Wurzburg Riese 2. Damaged Riese with IFF antenna on top of the reflector. [ATTACH]137555[/ATTACH] [ATTACH]137556[/ATTACH] [I][B]Wurzburg Riese G[/B][/I] The Riese transmitted a very narrow beam which made it difficult to acquire the target. To assist with this, some variants (called Riese G, or Gustav) had a small inbuilt Freya, whose 50 degree wide search beam would acquire the target initially, after which the Wurzburg section would take over for measurements and control. The Riese G was particularly useful for detecting very high flying Mosquito formations which went undetected by other radars. [U]Attachments[/U]: 1 Riese G antenna with attached Freya antenna. [ATTACH]137557[/ATTACH] [CENTER]-----"----- [/CENTER] [U][B]Discovery[/B][/U] The first inkling the British had of the existence of a Wurzburg device again came from the Oslo Report: ". [I]. . another method is in the preparatory stage, which uses 50 cm waves. The transmitter broadcasts short pulses, which are sharply focused with a concave electric reflector[/I].” It is now obvious a Wurzburg radar is being described here, although the name would not be known for some time. The first mention of ‘Wurzburg’ came from an Enigma decrypt in February 1941, which said that a Freya and a Wurzburg were being sent to Rumania for coastal protection. From this it was assumed that Wurzburg was another type of radar, but it still wasn’t known if this was the device described in the Oslo Report. By monitoring signals received along the south coast of England, a pulsed signal of 53cm wavelength with a PRF of 3,750 was identified as coming from the Channel coast of France. The next step was to locate and photograph the source of this transmission, but a 53cm radar would not be very large, and first they had to know where to look, and what to look for. It was assumed that it would be located close to a Freya installation for security, so PR aircraft were sent to photograph every Freya station as soon as they were located in the hope of finding one. It wasn’t until Autumn 1941 that a very small dot was seen on a photograph of a Freya station at Cape d’ Antifer (20 miles north of le Havre) near the village of Bruneval. A low level PR Spitfire flight to get a close up of the dot was organised. The pilot excelled himself; he flew past twice and obtained two photographs, which became classic photographs of WW2. They showed a small radar with a concave reflector – just what they were looking for. [U]Attachment[/U]: 1. The Wurzburg at Bruneval. [ATTACH]137559[/ATTACH] [U][B]The Bruneval Raid[/B][/U] [[B]Note:[/B] The story of the Bruneval Raid to too well known to repeat here, so only an outline is given.] It was Churchill’s policy to mount nuisance raids on the French coast to keep the Germans occupied, so when it was suggested that such a raid could be mounted to capture the Wurzburg and bring it back to England for technical analysis, it was quickly approved and given the codename of Operation 'Biting'. Although the radar was on top of the 400ft cliffs, a long descent to a small beach was noted, which the French Resistance discovered not to be mined. Briefly, the idea was to drop paratroopers to capture the station, and a technician to dismantle the Wurzburg, then retreat to the beach where they would be picked up by the Royal Navy. The raid was launched on the night of 27 February 1942 and successfully executed with only a few casualties. Many of the important parts of the Wurzburg were seized, and its operator captured. All were brought back to England safely the next day. The radar parts were taken for analysis to the TRE (Telecommunications Research Establishment), which at that time was still located at Swanage. [U][B]Analysis[/B][/U] With the help of the captured operator, the parts were reassembled as far as possible. It was found to be a Wurzburg model A, one of the earliest. It was well engineered and of a modular design with parts easily replaced by relatively inexperienced personnel. One of the surprises was the low technical ability of the technician/operator. This low ability was general amongst German radar technicians and will be expanded upon in a later article. From the serial numbers and dates of replaced parts, it was calculated that Telefunken was producing around 100 sets per month. Its wavelength was fixed between 53 and 54.2cm which could not be changed by the operator in order to avoid jamming. Also there were no inbuilt anti jamming devices, which enabled electronic countermeasures (ECM) to be devised. [U][B] German reaction[/B][/U] After the raid, coastal radar stations were more strongly guarded with a ring of barbed wire, which ironically made PR easier as the grass underneath could not be cut and rubbish accumulated, caught in the wire, making them stand out in aerial photographs. The Germans quickly realised that once the British had discovered that Wurzburg operated only on a single wavelength it became very susceptible to interference. At this time all German radars operated on single frequencies, so all were eventually modified to work on a range of frequencies to which the operators could change when required. [U][B]Further operations[/B][/U] Photo Reconnaissance revealed many Giant Wurzburg reflectors stacked up at the Zeppelin works in Friedrichshafen. On 20 June 1943 Operation 'Bellicose' was launched, in which No. 5 Group bombed the Zeppelin factory, then flew on to land in Algeria, North Africa where they were refuelled and re-armed. Unknowingly, the raid had the bonus of destroying the new V2 rocket parts production facilities. On the return flight they bombed the Italian naval base at La Spezia in the first shuttle bombing raid. [CENTER]-----"----- [/CENTER] [I](Continued)[/I]
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[quote=Scatari;10091171]A fascinating thread Bill - many thanks for all your efforts. One question - was it a "Freya" installation which was one of the objectives of the ill-fated raid on Dieppe in 1942?[/quote] Hello Tim, It was one of the ojectives, but only a very minor one. There was a Freya installation nearby, and a radar technician had been taken along to look at it, in case it was captured (I don't think it was). But really it was very much a sideshow.


[QUOTE=emason;10091190]Hello Tim, It was one of the objectives, but only a very minor one. There was a Freya installation nearby, and a radar technician had been taken along to look at it, in case it was captured (I don't think it was). [B]But really it was very much a sideshow[/B].[/QUOTE] Understood Bill - just wasn't sure which type of installation it was, but you have answered my question. Thanks.


Thanks for the amplification on my points & for part IV of the article. I think I see how it works now. If the UHF beam is narrow enough & the squelch/AGC threshold of the aircraft IFF receivers is set intelligently it won't un-necessarilly activate the IFF of aircraft (ie possible targets) off beam. The HF/VHF IFF receive dipoles should have in phase signals for aircraft on the same azimuth heading. Thanks again, Pete


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 5)[/I][/B][U][B] The air defence problem[/B][/U] Unlike the British prior to WW2, the Germans had given little thought to air defence, being pre-occupied with the offensive in general and Blitzkrieg in particular. Perhaps being confident of military success, resistance and retaliation by the enemy were considered unlikely and air defence was therefore neglected. Also, concerns about air defence were dismissed as being ‘defeatist’. Whatever the reason, there was no overall strategy or organisation for the defence of the Reich. Instead there was only a piecemeal distribution of localised searchlight and Flak batteries to protect mainly large cities and military installations. Radar seemed to be treated in a similar manner, with little thought being given to coordination or integration. When it became obvious that Britain was not going to roll over, Goering, as head of the Luftwaffe appointed Colonel Josef Kammhuber in mid 1940 to organise Germany's air defences in the west against British bombing raids, but did not consult, or even inform, the Director of Luftwaffe signals, General Wolfgang Martini. When Kammhuber began, he inherited the visual observer network, sound location gear, searchlights, and 88mm Flak artillery. Kammhuber, did not at first appreciate the value of radar and organised the defences based only on searchlights and Flak batteries. General Martini knew that without radar this would be mainly ineffective, and sent him six companies equipped with Wurzburgs. Kammhuber did not at first know what to do with them, but after studying radar operation, he quickly recognised its value and reorganised the defences around ground radar. [U][B]The Kammhuber Line[/B][/U] Kammhuber realised that a defence in depth was needed to follow the bomber stream to have a greater chance of shooting down more of them before they reached their targets in Germany. For this he needed large numbers of searchlights and Flak, many of which, against opposition, were moved away from cities to much nearer the coasts facing Britain. Eventually, these would be employed in a continuous belt parallel to the coast stretching from Denmark all the way into France. This belt, now called the Kammhuber Line by the British, was divided into self contained defensive areas about 20km wide by 30km deep, into which Flak and searchlights were deployed in clusters to a depth of three. When radar was made available to him, he quickly integrated it into his system. Targets would first be detected by the long range Freya, and their location passed to one of the Wurzburgs, which would take over their tracking when within its range. Wurzburgs were able to determine their azimuth, range and height with enough accuracy to guide the searchlights quickly onto to them. [U][B]Control of Night Fighters[/B][/U] Initially, there were few night fighters available and, having no airborne radar to guide them in the darkness to their target, they were mainly ineffective. When they were used, the target had first to be illuminated by searchlights, and the Flak ordered not to fire, before they could attack. Without searchlights, it was very difficult with these early Wurzburgs to guide a night fighter onto its target, because of their limited range. By the time the target had been identified as hostile and its position determined with enough accuracy to make an interception, there was little time left to guide the night fighter onto its target before it was out of the Wurzburg’s range. The night fighter would be sent up to circle a radio beacon until called upon. It required two Wurzburgs to make an interception; one to follow the target, the other to follow the night fighter. The position of each was sent to a control centre which plotted both, then guided the night fighter onto the target. This required great accuracy, but these early Wurzburgs weren’t accurate enough to make an interception certain, particularly in reduced visibility which required the pilot to be much closer to the target before he obtained visual contact. This improved when the Giant Wurzburgs became available. With their much longer range and improved accuracy, these were precision instruments which could be used for night fighter interception or for direct gun laying. Shortly after their introduction, Hitler ordered most of the searchlights back to Germany where they could make a show of defending towns and cities. Later, the line was considerably deepened and, when night fighters were available in numbers, the line was divided along its length into two zones. The outer zone, (nearest the coast) was the exclusive domain of the night fighters; while the inner zone was allocated to searchlights and Flak. [U][B]The Himmelbett[/B][/U] Himmelbett was the name given to a self contained defensive site in which there was a Freya, two Giant Wurzburgs, a plotting and control centre, and usually two listening posts of the Y-Dienst. As the two Wurzburgs continuously reported the positions of the target and night fighter to the plotting centre, their positions were manually projected, as points of coloured light, onto a plotting device called a ‘Seeburg Table’, with a red point for the target, and a blue point for the night fighter. The controller would then issue commands to the night fighter to guide it to the target. [[B]Note:[/B] The Seeburg table resembled a four-poster bed with a canopy. Perhaps this is the origin of the name Himmelbett, which in German means four-poster bed.] [U]Attachments[/U]: 1. A Himmelbett site. 2. A Seeburg table (From a sketch made by a Belgian agent.) [ATTACH]137603[/ATTACH] [ATTACH]137604[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]British countermeasures[/B][/U] Bombers flying into Germany or France couldn’t avoid the Kammhuber line, and would have to cross it at some point. But, as technically advanced as each Himmelbett site was, they had their weaknesses which could be exploited. [I]Firstly[/I], only one night fighter could be directed onto one bomber at a time, so the first tactic tried was to send the whole bomber force in a compact formation through the same section of the line to overwhelm the defences in a short space of time. This was moderately successful, but it was difficult to reassemble and maintain formation after a raid for the return flight, and most losses were incurred while returning home. Kammhuber responded to this by increasing the number of stations to deepen the defensive line. [I]Secondly[/I], the Wurzburgs were a potential weak link. If either of them, for any reason, were unable to report accurately, the whole site was rendered inoperable. To exploit this, two types of ECM (Electronic Counter Measures) were used. The first, called ‘Mandrel’, was simply a noise generator transmitting on the Wurzburg’s wavelength to mask the return signal. The second, called ‘Moonshine’, was more subtle. It was a ‘spoof’ system intended to deceive the Wurzburg operator into believing that he was seeing a large force of aircraft, when in fact there was only one. The Moonshine device received the Wurzburg’s transmitted pulse, and returned it amplified and duplicated, giving the appearance of a large number of aircraft. If the Wurzburg operator selected one of these many false echoes to follow, the night fighter would find nothing there. [I]Thirdly[/I], the voice communication channel between the plotting station and the night fighter could be disrupted by jamming or, as was done later in the war, by British German speakers impersonating the ground controllers and transmitting false instructions to the night fighters. Needless to say the Germans devised methods and tactics of their own to counteract these countermeasures, and the British devised different tactics and ECM systems, including ‘Window’. And so the electronic war went on, until late 1944 when much of the Kammhuber line was overrun by the advancing Allies. [U][B]A night fighter control ship[/B][/U] An interesting variation of a Himmelbett site was the night fighter control ship [I]NJL Togo[/I], which acted as a forward extension to the Kammhuber Line. The [I]Togo[/I] was originally a merchant ship converted to an auxiliary cruiser which was to be named [I]HSK Coronel[/I] once she was at sea, but she never made it. Her passage was deduced from Enigma intercepts, and she was attacked and damaged while attempting to transit the English Channel, forcing her to return. After which she was converted to the radar ship. She was equipped with a Dreh Freya forward (the one with PPI – remember?), a Giant Wurzburg aft and two Y-Dienst receiver towers. The Y-Dienst was a passive signals intercept operation, which used directional antennae and triangulation to locate bomber formations from their radio emissions. The Y-Dienst had the advantage of being impossible to jam, and was an important element of the German air defence system. The [I]Togo[/I]’s only known success occurred on the night of 21/22 January 1944, when a bomber formation, with Berlin as their target, was detected by the [I]Togo[/I] and intercepted by night fighters while over the North Sea, still 160 km from the coast. [[B]Note:[/B] In WW2 the Allies used similar radar equipped ships called Fighter Direction Tenders for the Normandy landings.] [U]Attachments[/U]: 1. [I]NJL Togo[/I]. The ‘minarets’ contain the Y-Dienst antennae and receivers. 2. Another view of Togo. [ATTACH]137605[/ATTACH][ATTACH]137606[/ATTACH] [U][B]Afterwards[/B][/U] General Martini the Director of Luftwaffe signals, when interrogated after the war was asked why the Freya-AN wasn’t used for night fighter interception, said that, “[I]Kammhuber preferred the Seeburg Tisch method of plotting to the Freya-AN system, because he said that the former method of control could be understood by all but the latter could be managed successfully only by special gifted officers.[/I]” Martini was disappointed because he considered the Freya-AN to be superior and there were enough capable young officers in his organisation to have worked with it. It would have been simpler and better if a single radar could have been used, which would have eliminated the need for the Seeburg Table. The important factor was the relative position of the two aircraft from each other, not their absolute location. So any inaccuracy in the radar measurements would apply equally to both aircraft, so their relative position would be the same. It was due only the Riese’s accuracy that Kammhuber’s complicated system worked. “[I]There was no cathode ray presentation such as we ourselves employed, and the plotting system was therefore ponderous and liable to human error.[/I]” – R.V.Jones. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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In post #14, I stated that: [quote]3. Both types of IFF received at the same wavelength as the radar but required a different PRF, and normally responded on a different wavelength.[/quote] This is only true for the early radars with a fixed wavelength. Once the radar wavelengths could be changed to avoid jamming, (as was the case with all later models), a separate transmitter (codename 'Kuh' - Cow) was fitted to each radar which sent the IFF signal at the wavelength the IFF sets in the aircraft required. This was 2.40 metres for the GEMA 'Erstling' which responded on 1.90 metres.


[CENTER][B][U]The Development of German Radar in WW2[/U][/B] [/CENTER] [B] [I](Part 6)[/I] [U] Freya derivatives[/U][/B] As the war progressed and the bombing of Germany intensified, it became imperative for the Germans to detect approaching aircraft earlier, and at a greater distance, in order to have time to organise the fighters and disrupt the bomber formations before they reached their targets. The longest range radar available was the Freya, but its range of about 150km, dependant on the height of the target, was not considered sufficient. The power of Freya’s transmitters couldn’t easily be increased to increase the range, and efforts were made in 1942 to produce a radar with greater range. It was reasoned that the combined power of multiple Freyas would have the required effect until more powerful transmitters could be developed. Various configurations of multiple Freya antenna arrays were experimented with, and two basic arrangements emerged from this; a vertical stack of arrays called ‘Wassermann’, and a matrix of arrays called ‘Mammut’. The Wassermann improved the range to about 200-250 km, while Mammut extended this to about 300 km. These multiple antenna arrays not only had greater range, due to their combined power, but were also more accurate. They were deployed mostly along the coasts of Denmark, Holland, Germany, Belgium and France, to detect bomber formations approaching from England as early as possible. [CENTER]-----“----- [/CENTER] [U][B]Mammut [/B][/U](FuMG 401) Mammut was a long-range, early warning radar developed by GEMA in 1942; it was equivalent to eight Freya antennae arrays, arranged in a four wide by two high configuration. It measured 25 metres wide and ten metres high and was mounted on four pylons fixed in concrete. Some Mammuts had an identical arrangement on the rear of the pylons to track aircraft inland once they had passed by. This was to detect changes in the bomber’s course, and therefore their potential destination. Mammut's characteristics were similar to that of Freya, with the same 2.4 metre wavelength and 500 Hz PRF. However, Mammut’s much higher peak power of 200 kW, gave it double the range of Freya. It used horizontal lobe switching to obtain an azimuth accuracy of about half a degree. Again like Freya it couldn’t determine altitude, but it primary purpose was long range warning. Although the position of this huge array was fixed, the transmitted pulses could be directed electronically by up to 50 degrees to either side, giving a 100 degree arc in front which was continuously scanned. Mammut was the world's first phased array radar and was able to detect targets flying at an altitude of 20,000ft from 300km, at 3,000ft from 200km, and low flying aircraft at 150ft from 35km. Range accuracy was ±300m and azimuth accuracy ±0.5°. [[B]Note:[/B] There was a smaller version of the Mammut operated by the Kriegsmarine as ‘coastwatchers’. These can easily be recognised as having a similar appearance but with only three support pylons. From their appearance, it is not obvious that they are using Freya antennae, as their dimensions don’t seem to match. It is possible therefore, that the multiple arrays these are using derive from some other naval radar.] [U]Attachment[/U]: 1. Mammut with arrays front and rear. 2. Smaller Kriegsmarine version. [ATTACH]137635[/ATTACH][ATTACH]137636[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]Wassermann [/B][/U](FuMG 402) The Wassermann used a different approach to the antenna arrangement used by Mammut. Instead of a matrix of arrays, a stack of arrays was used. It was hoped that the extra height would give it a longer range. A prototype was built of four Freya antennas set up one on top of the other on a 36-meter high trellis mast. This in turn was mounted to a rotatable stand. In the centre of the antenna field, the IFF antenna was mounted. Wassermann used electronic beam steering and lobe switching to achieve an azimuth resolution of about 0.25 degree. Characteristics were similar to Freya's, except that Wassermann produced a peak power of 100 kW and had a range of over 200km. There were a number of different versions of Wassermann, but they all essentially amounted to the equivalent of six or more Freyas mounted on a rotatable tower. Wassermann were built in three versions – light, medium and heavy. About 50 of all versions were built, with the first going into operation in 1942. [Note: There is considerable confusion about the equivalent number of Freya arrays used in each configuration. I have used Light=6; Medium=8; and Heavy=12, which may not be entirely correct but is near enough.] [I][B]Wassermann L[/B][/I] (Leicht – Light) This was produced by GEMA and consisted of a 30 metre high array of six, vertically polarised, Freya antennae mounted on a rotatable trellis mast. It had a range of 200 km with an azimuth accuracy of ± 0.5° and range accuracy of ±5 km. Two types were manufactured, namely L.I on 2.40 metres and L.II on 2.01-2.27 metres, in which the frequency could be changed at 15 MHz intervals. About 25 of these were built. They were constructed as lightly as possible for easy transportation. It was estimated that they took about 3-4 weeks to erect. They had a disadvantage that in strong winds the whole tower was susceptible to being blown over. [U]Attachments[/U]: 1. Wassemann L [ATTACH]137637[/ATTACH] [I][B]Wassermann S[/B][/I] (Schwer - Heavy) The Wassermann S was again built by GEMA, and had double the number of vertically polarised Freya antennae as the Light. These were attached to a self supporting, rotatable steel tower having a diameter of four metres and a height of 60 metres. This stood in a concrete base and was rotated by a large toothed gear drive. The first equipment was erected towards the end of 1942, and in all some ten became operational. The first seven used wavelengths of about 2.40 metres; the others used 2.30 metres. These sets took something over 4 months to build, but they were more robust than the Wassermann L. Even by using more powerful transmitters, the range of the Wassermann S at around 300 km was less than hoped for. The azimuth accuracy was ±3 degrees. [U]Attachments[/U]: 1. Wassermann S front view 2. Wassermann S rear view [ATTACH]137641[/ATTACH][ATTACH]137642[/ATTACH] [I][B]Wassermann M [/B][/I](Mittel - Medium) The Wassermann M was produced by Siemens and Halske from the autumn of 1943 onwards. Its five models showed improvements over the L and the S models. The first, the Wassermann M1, had a 36-metre high trellis mast supporting eight Freya antennae and was similar in design to the L version. However it used lobe switching and had a few other improvements. Its accuracy in azimuth and range was about the same as the L and S variants, but a maximum range of only 220km was obtained. The transmitter mast for the Wassermann M2 was 40 metres high, plus the IFF system and its associated antenna. It had a wider, horizontally polarized antenna array which could determine the height of aircraft. Both the M1 and M2 used single frequencies in the 2.01-2.20 metre band, but the M2 allowed different frequencies within this band to be used. The M3 used the 1.20-1.90 metre band, but only two sets were built as it was succeeded in the spring of 1944 by the M4 which gave wide band facilities from 1.90-2.50 metres. Some twelve M4 were in operational use by January 1945, and more were being produced. The last form of Wassermann was to have been the M5 which worked on a wide band of 2.50-4 metres, of which one experimental set had been set up on the Baltic coast. With the Wassermann M4 and M5, the operations cabin was located in the centre of their masts. [U]Attachments[/U]: 1. Wassermann M2, showing horizontal dipoles with vertical IFF dipoles at the top. 2. Wassermann M2, another view. 3. Wassermann M4, with operator’s cabin in the centre of the antenna array. [ATTACH]137638[/ATTACH][ATTACH]137639[/ATTACH][ATTACH]137640[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]Conclusion[/B][/U] Generally speaking, the Wassermann was a disappointment, as it had been expected that its range would be about 400km, but rarely achieved much over 250km. Production of other long range radars were postponed, as efforts to increase Wassermann’s range were given priority. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [I][B](Part 7)[/B][/I][U][B] Wurzburg developments[/B][/U] The Wurzburg was probably the most successful German radar with over 4,000 units deployed by the end of the war; but development from the basic model continued, producing several new radars of advanced design, the first of which was the ‘Mainz’. [U][I][B]Mainz [/B][/I][/U](FuMG 63) The Mainz, introduced in 1941, was a development from the Wurzburg with its three metre solid metal reflector mounted on top of the same type of control car as used by the Lorenz ‘Kurmark’. Its range was 25-35km with an accuracy of ±10-20 metres, azimuth 0.1 degrees, and elevation ±0.3-0.5 degrees. Despite its high azimuth accuracy, it wasn’t considered better than a Wurzburg due to other unspecified shortcomings. Only 51 units were produced before being superseded by the ‘Mannheim’. [U]Attachment[/U]: 1. Mainz FuMG 63, with IFF above. [ATTACH]137692[/ATTACH] [CENTER]-----“----- [/CENTER] [U][I][B]Mannheim [/B][/I][/U](FuMG 64) The Mannheim was an advanced development from the ‘Mainz’. It also had a three metre reflector, which was now made from a lattice framework covered in a fine mesh. This was fixed to the front of a control cabin and the whole apparatus was rotated electrically. Its range was 25-35 km, with an accuracy of ±10-15 metres; azimuth and elevation accuracy of ±0.15 degrees. This accuracy came at a price, for the Mannheim’s controls and electronics were complicated and expensive to manufacture. When it was introduced in late 1942, it was the most advanced radar available. Not only was it accurate, but once the operator had acquired the target it could be locked onto and tracked automatically. There was no operator oscilloscope, instead instruments were used which fed a mechanical range and elevation computer whose output could be sent to a control centre by radio. Later, the Mannheim would be used to control a Flak battery. Up to 4 guns (fitted with the ‘Rettin’ radar), and the Mannheim, could both be linked to a operations control van codenamed ‘Bayern’. Once the Mannheim had picked up a target it fed tracking data to the Bayern’s analogue computer. The individual flak guns would then be instructed to train towards the target. The Rettin radar in each linked gun would then send its own radar data to the computer to calculate the target range, direction, and speed to calculate a firing point. This result of this computation was sent directly to the optical reflector gun sight; the gunner then trained their gun to the dot and fired. No visual contact was required for the gunner to engage his target, which meant the system could operate at all times of day and night and in all weathers. The accuracy of the Mannhein’s elevation measurement was susceptible to errors from to ground reflections. To remedy this, some models were fitted with a 2.5 metre long ‘bottom lip’ of wire mesh to shield the antenna. [U]Attachments[/U]: 1. Mannheim FuMG 64. 2. A pair of same. 3. Mannheim with shielding. [ATTACH]137695[/ATTACH][ATTACH]137693[/ATTACH][ATTACH]137694[/ATTACH] [CENTER]-----“----- [/CENTER] [U][I][B]Mannheim Riese[/B][/I][/U] (FuMG 75) Just as the Wurzburg’s performance was greatly improved when fitted with a 7.4 metre reflector, so was the Mannheim’s, and the result called a Mannheim Riese (Giant Mannheim). The antenna and reflector were separate from its controls which were now housed in a ‘Bayern’ remote control truck. The range of the system was 84 km with an accuracy of ±12 metres. The azimuth and elevation error was ±1 - 1.5 degrees. There was an optical device for the initial visual acquisition of the target. With its narrow beam it was relatively immune from ‘Window’. Its accuracy and automatic tracking enabled it to be used in anti-aircraft missile research to track and control the missiles in flight. Only a handful of Mannheim Riese were ever produced, and it didn’t go into full production. [CENTER]-----“----- [/CENTER] [U][I][B]Ansbach [/B][/I][/U](FuMG 68) There was a need for a mobile radar with the range and accuracy of the ‘Mannheim’. The result, in 1944, was the Ansbach. It had a collapsible reflector of diameter 4.5metres, operating on a wavelength of 53.6cm, and peak power of 8 kW, giving it a normal range 25-35km (70km in search mode) with an accuracy of 30-40 metres. Azimuth and elevation accuracy was around ±0.2°. The antenna and reflector were remote controlled from a Bayern control van up to 30 metres away. The Ansbach was to be installed in large Flak batteries with six or more guns, but only a few were produced by the end of the war, and these didn’t see operational service. [U]Attachments[/U]: 1. Ansbach FuMG 68. 2. Bayern control truck. [ATTACH]137696[/ATTACH][ATTACH]137697[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 8)[/I][/B][U][B] Panorama radar[/B][/U] Most of the long range radars were deployed along the Channel and North Sea coasts facing England, but once a bomber stream had been detected it was necessary to follow its progress inland to determine its destination. The best solution for this would be radar giving a panoramic view of everything around it. GEMA started development of such a system in about 1939 from an earlier idea of Hans Hollman. Development progressed to the point where a prototype, codename 'Panorama' was constructed from Freya electronics. Consequently, ‘Panorama’ became the general German term to describe any radar type giving a 360 degree field of view with a Plan Position Indicator (PPI) display. It was erected in 1940 on top of the Tremmen Radar Tower, situated about 40km west of Berlin. The antenna consisted of a row of eighteen full wave dipoles mounted vertically on a horizontal beam which rotated at six rpm. It operated on the usual Freya wavelength of 2.4m. Problems were experienced with it and further development hardly progressed at all, as GEMA's other radar developments were given priority and the Panorama became rather neglected. It wasn’t until the beginning of 1943, that interest in Panorama was rekindled after General Martini was berated by Goering for neglecting it. Martini wanted to see the Panorama to assess it, but was told that it had not yet been perfected, so he sent two members of his staff to try and overcome the technical difficulties. Three months later he was told it was ready, but after two hours inspection, it still couldn’t be made to work properly and further development was abandoned. [[B]Note:[/B] GEMA did develop a successful panoramic radar but it was a development of the Freya called Dreh-Freya, also known as the Freya Panorama, but it had a range of only about 100km.] [U]Attachment[/U]: 1. Panorama mounted on the Tremmen tower. [ATTACH]137720[/ATTACH] [CENTER]-----"----- [/CENTER] [U][B]Other prototypes[/B][/U] Several other projects were initiated to produce a panoramic radar - not all were successful. [U][I][B]Propeller[/B][/I][/U] Another failure was experienced in 1943, this time by Lorenz. GEMA had been compelled by the Luftwaffe to hand over its development work on the Dreh-Freya (PPI radar) to Lorenz. It is probable that, from the experience gained by this, Lorenz was able to build their own Panoramic radar which they named ‘Propeller’. This relied on rapid rotation of the antenna and used a wavelength of about 50 cm. But just before it was demonstrated to the Luftwaffe, it was burned out in a fire and everything was lost, so Lorenz abandoned the project. [U][I][B]Jagdschloss Michael B [/B][/I][/U] Telefunken also had a go with their ‘Jagdschloss Michael B’, whose antenna was a huge horizontal array of two rows each of which was equivalent to eighteen Würzburgs, measuring 56m long and 7m high. The antenna was so large that it had to be supported by rollers running in a track. The wavelength was the same as the Wurzburgs, but it couldn’t be made ready until April 1945. [[B]Note:[/B] A similar antenna array mounted vertically was used in another of their early warning developments named ‘Wurzmann’, which will be described later.] [U][I][B]Forsthaus F[/B][/I][/U] Another Telefunken project was ‘Forsthaus F’. This was designed to fulfil the same purpose as the Jagdschloss Michael B, but using wavelengths of 25-29cm. Again, a very long antenna array 48 metres long and about 8 metres high was used, with a reflector resembling a half cylinder with a parabolic cross section. It is not known if it ever became operational. [CENTER]-----"----- [/CENTER] [U][B] Jagdschloss[/B][/U] The first successful PPI radar which came into operation is usually referred to as the Jagdschloss, although it’s official designation is Jagdschloss F. It was produced by Siemens & Halske using GEMA supplied electronics, and went into operation in early 1944. The antenna was 24m wide and 3m high, consisting of sixteen pairs of double horizontal transmit and receive dipoles. Above this, an 8.5 metre wide antenna array of eight vertical dipoles was mounted for the IFF. They were equipped with new GEMA electronics operating on one of two bands; 1.2-1.9m or 1.9-2.5m. This antenna arrangement generated a narrow radar beam in the shape of a vertical fan, with good horizontal resolution but little or no altitude determination capability. The whole array rotated and a PPI displayed the results. In favourable conditions, high flying aircraft could be located at a distance of about 300 km, but 150km was the norm. The first 62 Jagdschloss built by Siemens used wide band antenna covering the band 1.90-2.20 metres. Another 18, (said to be assembled by Lorenz) used the band 1.20-1.90 metres. Although Jagdschloss was initially designed for long range early warning, as the war progressed they became increasingly used for fighter direction. The PPI could operate in any of three display modes: targets only; fighters (IFF) only; or targets and fighters together. An optional feature known as Landbriefträger (Postman) was a remote PPI display for use with Jagdschloss. This allowed the PPI display from the radar station to be sent simultaneously to command HQ by HF cable, or by a UHF radio link. [U] Attachments[/U]: 1. Jagdschloss diagram. 2. Jadgschloss photograph. 3. Another Jagdschloss. [ATTACH]137721[/ATTACH][ATTACH]137722[/ATTACH][ATTACH]137723[/ATTACH] [CENTER]-----“----- [/CENTER] [B][U]Other panorama radar[/U][/B] [I][U][B]Jagdhutte[/B][/U][/I] Jagdhütte, again produced by Siemens, was a reduced version of Jagdschloss without the radar antenna, but with a double size (16 dipoles) 17 metre wide IFF array. This was for control of German fighters only, giving a panoramic display of their IFF responses. In this way friendly fighters were to be controlled from the ground at ranges up to about 300 km. Due to the different transmit and receiving IFF frequencies, it was resistant to ‘Window’. But it was known that if either frequency were ever jammed, the Jagdhütte would be useless; but this was considered unlikely. The first Jagdhütte was erected in January 1945, and by the end of the war about 9 were built, but there is no information as to how successful they were. [U]Attachment[/U]: 1. Jagdhutte diagram. [ATTACH]137724[/ATTACH] [CENTER]-----“----- [/CENTER] [U][I][B]Forsthaus KF[/B][/I][/U] This was a Telefunken project to introduce as rapidly as possible a panoramic early warning radar on an unused wavelength. This was a smaller form of the Forsthaus F (see above), and to be introduced while the F was being completed. It was designed so that it could be used on a railway wagon; the revolving aerial array was 24 metres long and it was expected to give a range of 120 km. The wavelength and electronics used were the same as in the Forsthaus F. It is not thought that it was put into production due to the rapid development of centimetric radar, rendering it obsolete by the later centimetric 'Forsthaus Z' (described later). [CENTER]-----“----- [/CENTER] [U][I] [B]Jagdwagen[/B][/I][/U] Jagdwagen was a mobile Panoramic radar built by Lorenz to control fighters at close ranges immediately behind the front line. It was hoped to produce the Jagdwagen as a fully mobile panoramic set operated by a motorised company to install them on aerodromes so that a picture of the local air position could easily be obtained. The antenna array was only 8 metres long, and operated on wavelengths of 53-59 cm, giving it a range of about 50km for medium heights. In February 1945 the first sets were tried out. [CENTER]-----“----- [/CENTER] [U][B][I]Jagdhaus[/I][/B][/U] (FuMG 404) Jagdhaus was designed and built by Lorenz in 1944 as an early warning radar. It was the most powerful radar built by the Germans, with a peak pulse power of 300kW, which Lorenz planned to increase to 750kW. The whole assembly was the size of a house, which is possibly how it got its name; ‘haus’ being the German for ‘house’. The rotating upper part of the construction housed the separate parabolic transmit and receive antennae and reflectors, with the IFF above them as usual. It weighed 48 tons and rotated at 10 rpm. It operated on wavelengths of 1.4 to 1.8 metres, and had a range of about 300km. It could measure altitude, azimuth and range. The control room was located below the antennae, from which its PPI image was also transmitted to command HQ at Charlottenberg by Landbrieftrager, similar to the Jagdschloss system. It is believed that only one Jagdhaus was constructed, which fell into Soviet hands when it was captured by their troops in 1945, during which time it was damaged. The Soviets compelled the Germans to repair it and instruct them in its operation. [[B]Note:[/B] As an aside, the Soviets also captured the entire GEMA works when they occupied Berlin.] [U]Attachment[/U]: 1. Jagdhaus (unfortunately very poor quality, but the only one available.) [ATTACH]137725[/ATTACH] [CENTER]-----“----- [/CENTER] [I][U][B]Rundblick[/B][/U][/I] Rundblick was an early warning radar with a 360 degree field of coverage operating with an 11.4 metre wavelength. A 40 metre wide antenna supported eight vertical dipoles and was attached to the front of a rotating cabin. Ships and low flying targets could be picked out up to 60km, and high flying formations could be tracked as far as 230km. This radar is a bit of a mystery as it looks like an early type, but the use of the long 11 metre wavelength suggests a later date. There is mention of a ‘Jagdschloss Lang’ (long) with a wavelength of 8.0-10 metres, but no information about this has been obtained, so it is not known if the two are the same. [U]Attachment[/U]: 1. Rundblick [ATTACH]137726[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 9)[/I][/B][U][B] Klein Heidelberg[/B][/U] Klein Heidelberg was the codename give to a passive radar system devised in 1941 by Ober Postrat Scholz of the Central Research Establishment of the German Post Office. At the time it was regarded as an interesting concept but of little importance and no resources for its development were forthcoming. This changed in 1942, when Allied jamming of German early warning radar had reached such a stage that other methods for the early detection of bombing raids were being sought, and Scholz's system was resurrected . In 1942, Scholz in co-operation with Telefunken, developed the system and gave it the codename of 'Heidelberg' in the Telefunken convention of naming their radars after German cities. When and why it became 'Klein Heidelberg' - 'Little Heidelberg' is unknown, but may have reflected a less ambitious version of Scholz's initial concept. It was alternatively referred to by the Germans as 'Parasit - 'Parasite'. Klein Heidelberg (KH) wasn't a radar in the usual sense as it had no transmitter of its own. Instead, it exploited the transmission pulses emitted from the British Chain Home radar. This type of system goes by many names, such as Passive, Parasite, Hitch Hiker, Piggyback, etc. It is a type of bistatic radar in which the transmitter and receiver are usually widely separated. (Conventional radar where the transmitter and receiver are together is called a monostatic radar.) Almost any radar transmission can be used in this way, even, as in this case, one belonging to the enemy. Klein Heidelberg was used only in coastal regions along the North Sea and English Channel where reliable reception of Chain Home emissions was possible. The main antenna was usually piggy backed onto an existing Wassermann-S mast which made it difficult to detect visually. The array was 30m high by 22m wide overall, and consisted of 18 half wave dipoles arranged in 6 groups of 3, a quarter of a wavelength in front of a wire mesh reflector. [U]Advantages [/U] 1. It was completely undetectable, both electromagnetically, and to some extent visually. 2. Countermeasures were almost impossible, as jamming would also have effectively jammed the Chain Home radars. (But by the same token, the Germans couldn’t jam CH without jamming their own KH. It is probably for this reason that CH was rarely jammed.) 3. It was both simple and inexpensive, as no transmitting antenna and equipment were needed, and the receiving antenna was erected on existing Wassermann-S masts. 4. It gave the earliest warning. [U]Disadvantages[/U] 1. It was totally dependent on the enemy’s transmissions which could be switched off at any time. 2. It had poor resolution for targets roughly in line between the transmitter (CH) and receiver (KH). This would necessitate retuning the receiver to a different CH transmitter – a lengthy process. 3. It wasn't very accurate. [U][B] KH in operation[/B][/U] Klein Heidelberg worked by sensing Chain Home (CH) transmission pulses directly with a small auxilliary antenna, close to the main antenna, whose receiver was tuned to a particular CH station whose exact location, bearing and range was known. The CH signal was then used to synchronise the KH with the CH transmission pulses. The CH pulse started a circular trace on a cathode ray tube (CRT) divided into forty sections. The main antenna received the reflection of these pulses from the target and displayed them on the CRT. The time difference between the direct and reflected pulses, and therefore the extra distance travelled by the reflected pulses, described an ellipse on a map. On the map, the positions of the CH transmitter and of the KH were marked, which formed the foci of 40 ellipses drawn around them – one ellipse for each of the 40 marks on the CRT. Each KH station in operation had its own individually marked set of maps, one for each CH station. From the CRT, the operator read off the division in which the reflected pulse appeared and selected the corresponding ellipse on the map. The bearing of the target was provided by the main antenna, and where this bearing intersected the ellipse on the map, gave the position of the target. There was no elevation reading. [U]Attachments[/U]: 1. KH antenna 2. KH antenna on the rear of a Wassermann-S mast. 3. Close up of KH antenna. 4. KH receiver CRT. [ATTACH]137833[/ATTACH][ATTACH]137834[/ATTACH][ATTACH]137835[/ATTACH][ATTACH]137836[/ATTACH] [U][B]Performance[/B][/U] The first Klein Heidelberg system was established at Boulogne and became operational in August 1943. With this system, in good conditions, Allied aircraft could be detected when still over England, and could be followed all the way to Germany. As a result of this success, other systems were established in the Netherlands, Belgium and France. In all, six installations were established. The theoretical range of KH was 600 km. but the most distant contact measured with any success was at a range of 345 km. The accuracy of the system was not great, but it was good enough to provide early warning of an impending attack. The azimuth accuracy of KH was about ±10°. Its lack of precision left much to be desired, and there were numerous instances in which the operator had obtained a contact and reported the position, only to be told a few minutes later that there were no aircraft in the area concerned. The size of the target was also difficult to estimate, and it was only seldom that estimates of size of formations made by the operator agreed with those obtained by other means. [U][B]Countermeasures[/B][/U] From intercepted reports, it was known as early as 1942 that the Germans were conducting research into a “Heidelberg Gerat”, without knowing what it was. It wasn’t until a German radar operator from a Klein Heidelberg installation was captured and interrogated in the Autumn of 1944 that a picture started to emerge. From the information received, all the KH sites were identified and confirmed by photo reconnaissance. Once the workings of Klein Heidelberg were revealed, countermeasures were devised very quickly. These consisted mainly of methods to disrupt the synchronisation of the KH receivers with the CH transmissions. So from October 1944, the regular 25Hz PRF of CH was made irregular, by employing ‘oscillator pulse-blocking’ which suppressed some transmission pulses, and was known as ‘PRF jittering’. The Germans immediately noticed this change in the CH 25Hz PRF in October, but within a couple of months their engineers had devised a method of synchronising automatically, after which KH was able to continue working more or less as before. [[B]Note:[/B] It was also possible to confuse KH if two adjacent CH stations transmitted on the same frequency. Their pulses would arrive at the KH station at different times making synchronisation difficult. It was considered, but doubtful if this was ever used as there would also be mutual interference between the two CH stations.] [U][B]Summary[/B][/U] Klein Heidelberg was an innovative answer to the increasing effectiveness of Allied ECM, but its inaccuracy and unreliable results, perhaps persuaded the Germans that it was at best, a useful backup system when other radars were being jammed. Like many German inventions, it was deployed too late to have had any significant effect. Things may have turned out differently had the 1939 Graf Zeppelin (LZ130) airship flight along Britain's east coast to monitor radio signals, correctly identified the CH signals they received as radar transmissions instead of the radio-navigation signals they assumed. The Germans at this time didn’t appreciate the potential of longer wavelength (HF) radar. Consequently, they were looking for radar signals in the VHF and UHF bands that their own radar used, and from this assumption they concluded that the British had no air defence radar. Had they drawn the right conclusions, KH could have been deployed up to two years earlier. It would be another 25 years before the concept was re-invented in the USA called “Sugar Tree” which used Soviet transmitted HF signals to detect ballistic missile launches. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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This is a fantastic thread, please keep them coming.


Thanks Barry, more to come, but finding information is proving problematic.


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 10)[/I][/B][U][B] Longer range radars[/B][/U] In the search for radar with a range longer than either the Mammut or the Wassermann, the main line of development was to use longer wavelengths in the HF band. German radar scientists had been investigating the potential of HF (over 10 metres) radar since the autumn of 1941, and had begun to appreciate that substantial ranges could be achieved. Radar at these wavelengths had an additional advantage of not being jammed at this time. Therefore the main German trend in avoiding British radar countermeasures was to use these longer wavelengths. Radar using these long wavelengths were intended to be used only when jamming disrupted other early warning systems. They were operated for only a few seconds at a time in order not to compromise the wavelength. The purpose was to obtain a picture of the air situation when other methods had failed. The wavelengths chosen were in the same HF band as the British Chain Home. The similarities between the systems subsequently developed and Chain Home were remarkable. [CENTER]-----"----- [/CENTER] [U][B]Elefant[/B][/U] One such radar called 'Elefant' consisted of a large high-power transmitter mounted on a 90 metre tall mast, separated by about 1,000 metres from the receiver antenna. It was partly designed by Ober Postrat Scholz of the Central Research Establishment of the German Post Office and built by Kothen. It operated on wavelengths from 7.5 to 15 metres with a PRF of only 25Hz. From its powerful 380kW transmitter, the beam was broadcast over a 120 degree wide arc from a fixed position, 100 metre tall transmitter tower. When the beam is as wide as this and not narrowly directed, it is known as ‘floodlighting’. The rotatable receiver antenna array appears identical to that used by Klein Heidelberg, but being mounted instead on a 51 metre tall Wassermann M4 mast. The operations cabin was mounted in the centre of the mast. The receiver was synchronised with the transmitter via a landline link so that the range of the target could be calculated. Ranges of about 350km were obtained. Elefant didn’t come into operation until 1944, as it was delayed when, in November 1943, permission was denied for its production as similar results were expected (but never obtained) from the Wassermann. But by the end of the war, three installations of this type had been deployed and a further three were in course of erection. [[B]Note:[/B] It is remarkable how similar its characteristics resembled those of Chain Home – a similarity which was not entirely coincidental. It is possible that Elefant was designed as an adjunct to the Klein Heidelberg parasitic radar, to be used when the CH transmissions were unavailable. There is no direct evidence for this, but both were bistatic radars designed in part by Scholz; the receive antennae were identical; and they both operated on the same long wavelengths as Chain Home, with the same PRF.] [U]Attachment[/U]: 1. Elefant transmitter antenna mast. 2. Elefant receiver antenna mast. [ATTACH]137913[/ATTACH][ATTACH]137914[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]See Elefant[/B][/U] Another experimental radar called ‘See Elefant’ was developed and first installed at Romo, Denmark in late 1944. Its transmitter antenna was mounted on 100 metre tall lattice masts. The operations room was located in the systems bunker of the nearby Mammut. It is believed that there was only one installation. It had a broad beamwidth (floodlight) which meant that it could only provide range information. A separate receiver antenna, about 1.5 km away (codename ‘Russel’) was synchronised with the transmitter via a landline link to provide the range and azimuth measurement. The ‘Russel’ antenna was similar in appearance to, but slightly different from, the KH and Elefant’s receiver antenna in having an extra cross arm and being mounted on a 70 metre tall mast. The antenna array had 32 elements, described as “[I]an array of broad band dipoles arranged in four bays stacked eight high with dipole reflectors behind, and supported on a single mast 220 feet high[/I].” Apart from their physical appearance, it is not known what the difference was between Elefant and See Elefant, nor why two very similar systems were developed almost simultaneously. [U]Attachments[/U]: 1. See Elefant transmitter antenna mast. 2. Russel receiver antenna mast. [ATTACH]137915[/ATTACH][ATTACH]137916[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 11)[/I][/B] [U][B]Würzmann[/B][/U] This Telefunken radar is a bit of an oddity as it doesn’t seem to have been used for early warning or air surveillance, although it was capable of this function. Its purpose seems to have been the long range tracking of low flying targets. It was operational in early 1944 and apparently was the only example. The name ‘Wurzmann’ could have been a combination of the names of Wurzburg and possibly Mannheim - two other Telefunken radars. Telefunken tended to do this for experimental radar and reserved German city names for production systems. [U][B] In operation[/B][/U] Its antenna array was mounted on two 36-meter high trellis masts and consisted of two adjacent columns, each of 16 stacked Würzburg elements. It doesn’t appear as if the masts could be rotated. With its peak power of 120kW and operating on the usual Wurzburg wavelength of 53cm, it produced a very narrow beam. It had a range of about 2-300km, and it was claimed that aircraft flying at zero feet could be detected at 20 km. In January 1944, while testing the Wurzmann, there appeared some strange echoes with a 2.5 second delay which disappeared after a short time. The antenna happened to be pointed towards the rising Moon, and when it passed out of the antenna beam, the signal disappeared. The operators repeated this the following evening with the same result. They were seeing the first known radio echoes from the Moon. [U][B]What was it used for?[/B][/U] Virtually nothing is recorded about the Wurzmann’s usage and the following is just conjecture, but the fact that only one was produced and it had no designated number (FuMGxx), would suggest that this was a special purpose radar for use at a single location. So what was so special about its purpose? [U]What it wasn’t used for[/U] As an early warning radar, its characteristics and location on Rugen make no sense. Other long range early warning radars were tested facing the opposite direction, towards Britain, near the Channel or North Sea coast, the nearest of which was over 300km to the west. [U]What is known about it[/U] [B]1.[/B] Its was erected on the island of Rügen, situated at the western end of the Baltic Sea, only a few miles north of Peenemunde, [B]2.[/B] When the Moon echoes were received, the antenna would have been directed roughly eastwards from where the Moon rises. [B]3.[/B] The mast appears to be set in concrete blocks, indicating that it wasn’t rotated. [B]4.[/B] Its beam was very narrow and could detect low flying aircraft. In summary, it was situated close to Peenemunde, faced eastwards, had a narrow beam, wasn’t rotated and could detect low flying aircraft. [U]Theory [/U] Peenemunde was the missile research centre which used the Baltic Sea as its missile test range, firing the missiles in a NE to ENE direction over 500km of water. From its location, the Wurzmann could provide radar coverage for almost the missile’s entire flight path without rotating; its narrow beam would be an advantage, as would its low level detection, especially for the V1 program. It is possible that it was used for tracking missiles (V1 and V2) launched from Peenemunde. Its characteristics made it suitable for this purpose. The following attachment shows the Wurzmann with a Lorenz Kurpfalz or Kurmark radar nearby – a curious combination. But if one accepts the missile tracking theory, then an explanation for the presence of the Kurpfalz/Kurmark emerges. A missile launched from Peenemunde, several miles to the south, wouldn’t come within the Wurzmann’s transmitted beam for the first part of its flight, arguably the most critical time. Perhaps the shorter range Kurpfalz/Kurmark was to fill this gap in the Wurzmann’s radar coverage. [U]Attachment[/U]: 1. Wurzmann and Kurpfalz/Kurmark. [ATTACH]137990[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 12)[/I][/B][U][B] Centimetric radar[/B][/U] Centimetric (SHF) radio waves had been researched in Germany in the 1930s; Hans Hollman had even patented a magnetron in 1935, but abandoned its development as its instability couldn’t be overcome. Around 1942, further research into centimetric wavelengths was abandoned in order to concentrate efforts in the metric and decimetric wavelengths. This all changed on 3rd February 1943, when a British Stirling bomber crashed near Rotterdam, Holland. During a normal investigation of crashed Allied aircraft, some unusual equipment was found. It was an H2S centimetric radar used as a navigation and bombing aid. Although it was damaged beyond repair, a strange new device was discovered (being almost solid, it was near indestructable). The device was a cavity magnetron (CV64), possibly the most significant single advance in radar development since its invention. It generated a SHF signal of 9cm wavelength with enormous power. The results of the examination of the equipment concluded that it was a new type of radar, far in advance of anything they had, or had even contemplated. The Germans were shaken by this discovery, which revealed to them just how far behind they had fallen in what General Martini had described as 'the high frequency war'. Not only was it more advanced than anything they had, but it was operational and working in a field in which they had abandoned research. Goering said of this, “[I]We must admit that in this sphere, the British and Americans are far ahead of us. I expected them to be advanced, but frankly I never expected them to get so far ahead. I did hope that even if we were behind, we could at least be in the same race.[/I]” In an action unprecedented in wartime, the Germans rapidly called together every radar expert to form a committee called the Arbeitsgemeinschaft Rotterdam (AGR) – the Rotterdam Working Group. (H2S was always referred to as the ‘Rotterdam Gerat’ – the Rotterdam apparatus.) At its first meeting, held on 22 February 1943, the AGR was given wide powers to unify industry and the scientific community in an effort to rapidly produce an answer to the threat of this new technology. [U][B]Industrial cooperation[/B][/U] Designing new technology and bringing it into production would take at least a year, so to give it a kick start and fill the gap it was decided to manufacture six (later extended to 20) copies of the H2S set. These copies were called ‘Rotterdams’. It was also decided to develop jammers (‘Roderich’) and receivers (‘Naxos Z’ and ‘Korfu’) to detect and locate the source of H2S emissions. Most German electronics and radar companies (with the exception of Lorenz) were involved to some extent in 'Rotterdam' manufacture, including Blaupunkt and Sanitas. Telefunken was to design a copy of a CV64 magnetron, designated LMS10, but Sanitas, a company making mainly X-Ray related devices, was to manufacture it. Sanitas made the LMS10s until its factory was destroyed in a bombing raid, whereupon production was moved to Telefunken. But Telefunken could only deliver five LMS10s per month until the end of December when Sanitas started up production again intending to produce 100 per month to meet the demand. The radar companies co-operated as never before. Telefunken provided Sanitas with a special test rig for testing the LMS10; and GEMA loaned a pulse modulator to Telefunken, as they were working on higher power magnetrons. [U][I][B]Berlin[/B][/I][/U] Apart from the ‘Rotterdams’, the first German H2S equivalent was made by Telefunken and codenamed 'Berlin'. This was a redesigned (or repackaged) H2S, to fit into the smaller space available in German aircraft. [U]Attachment[/U]: 1. Berlin A. [ATTACH]138141[/ATTACH] The codenames ‘Berlin’ and ‘Rotterdam’ are used synonymously in many accounts to describe German 9cm radar. The 'Berlin' became the basis for a number of experimental and prototype radars, and was used as a general codename for such systems, although all they had in common was they operated in the 9cm region. There were numerous centimetric radar systems under development, but in the short time available before the inevitable end to WW2, only a few models of land based centimetric radar were produced in time to become operational. [[B]Note:[/B] The operational airborne and naval centimetric radars will be described in later posts.] [CENTER]-----“----- [/CENTER] [U][I][B]Jagdschloss Z[/B][/I][/U] The Jagdschloss Z, developed by Siemens, was the centimetric equivalent of their successful Jagdschloss panoramic radar. The rotating antennae were about 24 metres long. It had an extremely narrow beam and so offered protection against jamming. The range expected was of the order of 100km, and although a prototype had been built, it was not expected to become operational until the second half of 1945. [U][I][B]Forsthaus Z[/B][/I][/U] The Forsthaus Z panoramic 9cm radar was the prototype of the ‘Kulmbach’. (See below). It differed from Jagdschloss Z mainly in the design of the antennae. The first test version was ready in August 1944. [U][I][B]Rotterheim[/B][/I][/U] (Rotterdam/Mannheim) This was the first fully functional German land based centimetric radar. It was a ‘Mannheim’, modified with the SHF 9cm ‘Berlin’ transmitter and receiver. Its range was about 30-35km ±30 metres, azimuth and elevation accuracy was ±-.05 degree. Its sharply focused beam was only 2 degrees wide which made it almost impervious to ‘Window’. In keeping with the Telefunken convention for naming its radars after German cities, its name was later changed to ‘Marbach V’ (FuMG 77). [U]Attachment[/U]: 1: Rotterheim. [ATTACH]138142[/ATTACH] [U][I][B]Marbach[/B][/I][/U] (FuMG 76) This was a further development of the 'Rotterheim' fitted with a rotating 9cm dipole, and a 4.5 metre reflector from the ‘Ansbach’, for greater accuracy and range. It also had an optical range finding telescope for daylight initial target acquisition. It was very advanced for its time, and only a few hand built examples were produced which became operational early in 1945 as part of the ‘Egerland’ system (see below). [U]Attachment[/U]: 1. Marbach FuMG 76 [ATTACH]138143[/ATTACH] [U][I][B]Kulmbach [/B][/I][/U](FuMG74) This was Telefunken’s production version of the prototype ‘Forsthaus Z’ panorama search radar. Its 6 metre antenna rotated at 20 rpm, and its reflector resembled a half cylinder with a parabolic cross section. It was remote controlled from a ‘Bayern’ operations van and was first operational early in 1945, when it was used as the search radar in the ‘Egerland’ Flak control system. It had a range of about 50km. Only two became operational. [U]Attachment[/U]: 1. Kulmbach 9cm panoramic. [ATTACH]138144[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]The Egerland system[/B][/U] The Egerland system was an air search and Flak firing system. It was comprised of the Kulmbach (FuMG 74) panoramic search radar; a Marbach (FuMG 76) fire control radar; and a Bayern operations van which contained the centralised controls for both radars, plus their instrumentation and measurement equipment, and provided firing data for the Flak guns. The Kulmbach searched the skies for 50km all around. Target positions were passed via the Bayern to the Marbach for accurate measurement. The target’s exact position was calculated and the firing solution passed onto the Flak guns. Smooth communication between the two radar systems made it possible to acquire and locate up to seven separate targets per minute, and pass the firing solutions to the Flak control. By the end of the war, only two Egerland systems had become operational. [[B]Note:[/B] For further details of radar controlled Flak, see under [U][I][B]Mannheim[/B][/I][/U] in Post #23 here: [URL]http://www.worldnavalships.com/forums/showpost.php?p=10091621&postcount=23][/URL] [U]Attachment[/U]: 1. Egerland with Marbach FuMG 76 and Kulmbach FuMG 74. [ATTACH]138145[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]Frischling[/B][/U] To make existing IFF sets compatible with these new 9cm wavelengths, a small unit called the 'Frischling' was fitted to every IFF set to convert the received SHF radar signal to the standard GEMA 'Erstling' receiver frequency of 2.4 metres. The response frequency of 1.90 metres remained unchanged. Frischling was to be produced by Telefunken but was still in course of development when the war came to an end. [CENTER]-----“----- [/CENTER] [U][B]Shorter wavelengths[/B][/U] In December 1943, an American aircraft crashed near the Dutch town of Meddo, close to the German border. It was carrying a type of radar the Germans had not seen before. This was the latest Allied development in centimetric radar, the H2X with a wavelength of 3.2 centimetres. A few months later, a complete and undamaged H2X unit was retrieved from an American aircraft that had made an emergency landing near Calais. The Germans referred to this as the ‘Meddo’ apparatus, and again, like ‘Rotterdam’ copied it, giving the prototypes the codename ‘Berlin D’. It is not known how many (if any) operational units (called ‘Bremen’) were produced as estimates vary from none up to 35. Additionally, receivers/detectors called ‘Naxos ZX’, capable of receiving 3cm transmissions, were developed. [CENTER]-----“----- [/CENTER]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Part 13)[/I][/B] [U][B] In retrospect[/B][/U] By the outbreak of WW2, both Britain and Germany had developed and installed defensive radar systems, and both were convinced that the other hadn’t. Initially the German radar was technically more advanced than the British, but after that, the Germans were content to improve what they already had instead of exploring the boundaries of the technology. Although having conducted research into centimetric wavelengths, they failed to pursue its development, abandoning it to concentrate their efforts in the metric and decimetric bands. The result of this was that while their technology improved, it failed to advance. The most striking example of this was the radar systems Jagdschloss, Wassermann and Mammut, which were all just variations of GEMA’s Freya; all using basically the same electronics first developed in the late 1930s, and all operating on similar wavelengths. There were however, three main events which forced them to look anew at their technology: [B][I]1. The Bruneval raid [/I][/B] The problem was that rigid frequency planning had fixed one spot frequency for each radar type. The Bruneval Raid woke the Germans up to the fact that this made their radar systems highly exposed to jamming which, in the event of it happening, would render them all useless. Several emergency measures were developed by Kothen who defined a range of frequencies, called Wismar, for each radar system. All current and future radar systems were modified to conform to this, so that they operated on a range of frequencies to enable radar operators to switch to unjammed frequencies. [I][B]2. Jamming[/B][/I] When jamming and other British electronic countermeasures began (probably sooner than the Germans expected) it forced them to explore ways of either avoiding it or minimising its effect, other than just by changing frequency. As the war progressed, the British intensified their ECM efforts by forming a specialist ECM Air Group (100 Group) to accompany bombing raids. Jamming increased and intensified to such a pitch that in order to avoid the complete breakdown of their radar defences, the Germans were forced to explore longer and longer wavelengths. This resulted in the Freya Kothen (Yagi) operating at 4-8 metres; the Jagdschloss Lang at 8-10 metres; the Rundblick at 11 meters; the Elefant and See Elefant at 10-12 metres; and the ingenious Klein Heidelberg at Chain Home wavelengths. It is rather ironic that it took the Germans five years to find it necessary (in See Elefant) to develop an equivalent of the British Chain Home, a radar system they believed not to exist in 1939, and thought inferior to their own when they discovered it did. [I][B]3. Discovery of H2S[/B][/I] The discovery in February 1943 of an H2S centimetric radar set aboard a crashed Stirling, forced them to confront the fact that they had fallen well behind in the ‘high frequency war’. Despite an unprecedented cooperative effort to bridge the technology gap, it was all in vain. Too few centimetric radar units became operational before the end of the war to make any difference. Although the few which did become operational had their successes, it was another case of too little and too late. [CENTER]-----“----- [/CENTER] [U][B]Where did it all go wrong?[/B][/U] From a position of German radar technical superiority at the outbreak of WW2, to their realisation that they lagged years behind the Allies in this field, took only three and a half years. How was this allowed to happen? The short answer is that there was no overall strategy for technical research for the air defence of Germany. There never existed anything like the Tizard Committee to direct and coordinate technical research in this field. Before the war, research and development of radar in Germany was the exclusive domain of scientists and technologists; and left to them Germany would probably advanced in parallel with America and Britain. But the paymasters for their inventions and discoveries were the armed forces, from whom the funds for further developments were slow in forthcoming. At the beginning of the war, Germany estimated that the war would be very short and all military planning was focussed on the offensive. Radar was viewed mainly as a defensive device and little thought or funds were spared by the High Command for its advancement. Among high ranking officers there were some exceptions, but they had learned to keep quiet as airing such ‘defeatist’ views would be detrimental to their careers. Consequently, until the summer of 1941 the Luftwaffe concentrated on offensive tactics, while neglecting defence. Hitherto, German radar had given good results, and among the hierarchy there was no incentive for research and development. In other words, they became complacent. The scientists probably felt otherwise, but by this time (mid 1941) all the radar companies were at full stretch fulfilling orders for current equipment and probably could spare little manpower for such projects. Added to this, Hitler’s order that projects which wouldn’t result in equipment being delivered to the front line in six months had to be abandoned, followed by orders to close the centimetre research laboratories in 1942, effectively halted radar research in its tracks. As the war progressed, Germany began fighting a more defensive war; and suffering both materially and politically from Allied bombing, radar technology assumed a greater importance. But when that Stirling bomber crashed near Rotterdam, they were finally confronted with just how far behind they had fallen in the ‘high frequency war’. Once it was realised that the Allies had an enormous technical advantage, the High Command was forced to change its mind radically. [U][B]Footnote[/B][/U] It is often said that the Germans had, by the end of WW2, caught up and bridged the radar 'gap' with the Allies. But in reality, they had only reached the stage the Allies were at when the Stirling crashed over two years before. Since that time, Allied developments, particularly American, had moved on apace. As an example, by April 1944 the Radiation Laboratories had already successfully tested radar (dubbed H2K) with a 1 cm wavelength. At the end of WW2, radar development in Germany was halted, and research into this area was forbidden by the Allies until 1950, when manufacture of British and American radar systems under license was permitted – but only for civil and maritime use. [CENTER]-----“----- [/CENTER]


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar – A.I. - Part 1)[/I][/B][U][B] Airborne Interception Radar[/B][/U] Telefunken, in the late 1930s, had been working on a radio altimeter based on radar principles. One of the applications envisaged for it was as part of a system to pull dive bombers out of a dive automatically; but the RLM (Reichs Luftfahrt Ministerium - Ministry of Aviation) showed no interest in it. However, General Martini (Director of Luftwaffe signals) did, but in a different role - as an airborne aircraft detector. He put this idea to Telefunken who then took the basic design of the altimeter and developed what is now known as the Lichtenstein Airborne Interception (A.I.) radar. The radar was completed in 1940, with its antenna consisting of four groups of quadruple dipoles mounted on the nose of the aircraft's fuselage. This arrangement was rejected by the Luftwaffe because it reduced speed and manoeuvrability, and an antenna integrated in the fuselage was demanded instead. However, after almost a year of argument and experiment, it proved impossible to mount the antenna internally. So the original arrangement was reluctantly accepted and the Lichtenstein finally entered service in 1941 - almost a year late. The Lichtenstein became available in at least four versions, designated Lichtenstein B/C (FuG 202), Lichtenstein C-1 (FuG 212), SN2 (FuG 220) and SN3 (FuG 228). [[B]Note 1:[/B] Airborne radar systems have the designation FuG xxx.] [[B]Note 2:[/B] It is now normal to refer to any German AI radar as being a 'Lichtenstein'; but it should really only be applied to Telefunken's first two operational models - the FuG 202 and FuG 212, as the SN2 (FuG 220) and SN3 (FuG 228) are completely different radar systems.] [U][B]Lichtenstein B/C[/B][/U] (FuG 202) From its introduction in 1941, the Lichtenstein B/C became the backbone of early nightfighter radar in 1942 and most of 1943. It operated on a wavelength of 61cm, with a peak power of 750 watts and a PRF of 2,700 Hz. Its normal range was 2-3km with a minimum range of about 150 metres. The range was limited by the nightfighter’s height, as below 1000 metres the ground returns (clutter) swamped the target’s return signal. When the Kammhuber belt was divided lengthwise into a nightfighter zone and a searchlight/flak zone, the nightfighter operated under control of a Himmelbett station which guided it to within range of its target. The first recorded success was on the night of 8/9 August 1941, when a Messerschmitt 110 shot down a British bomber. [U] Attachment[/U]: 1. FuG 202 antenna mounted on nose of Ju88. [ATTACH]138851[/ATTACH] [U][B]Lichtenstein C-1[/B][/U] (FuG 212) During 1943 the Lichtenstein B/C was improved as the Lichtenstein C-1 (FuG 212), with longer range and wider beam width, still operating at the same wavelengths. The wider beam width suggests a different antenna arrangement, but this cannot be confirmed. On 9 May 1943, the crew of a Lichtenstein equipped Ju 88 R-1 nightfighter defected and landed at Dyce airport in Scotland, presenting a working example of the German radar for the first time. The aircraft is still in existence and is now an exhibit at the RAF Museum at Hendon. [U]Attachment[/U]: 1. The Ju 88 R-1 at Hendon. [ATTACH]138852[/ATTACH] [U][B]Operator display[/B][/U] The Lichtenstein was operated by the navigator who issued guidance instructions to the pilot. The display consisted of three oscilloscopes – one each for range, azimuth and elevation. The attachment below shows a diagram of the azimuth and elevation displays from the longer range SN2 AI radar, whose display was similar to the B/C model, but without the range oscilloscope. [U]Attachment[/U]: 1. Operator display - diagram. [ATTACH]138854[/ATTACH] The diagram shows two targets between the transmit pulse and the clutter, at ranges of about 4.5 and 6km. Assuming the nightfighter is flying a level course, the nearer target, whose return signal is symmetrical about the centre line, is straight ahead and at same height; whereas the one farther away with the unequal signal, is to the right of, and below the nightfighter. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar - Part 1a)[/I][/B][U][B] The last piece of the jigsaw [/B][/U] By mid 1942 most aspects of the workings of the Kammhuber line were known to the British; however there was one item that was not known for certain. This was the wavelength of the Lichtenstein A.I. radar operated by nightfighters under control of a Himmelbett station. This intelligence was considered so important that they went to extraordinary lengths to obtain it. The following narrative is an abridged version of the subsequent search for this intelligence, taken from ‘Most Secret War’ by R.V.Jones. ”[I]The Lichtenstein Gerat, first came to our notice through a prisoner in April 1941, and it appears to have achieved its first operational success on 9th August 1941 when a Messerschmitt 110 from Leeuwarden shot down one of our bombers with its aid. In the ‘Little Screw’ radio telephony traffic between German controls and their nightfighters there was increasing use during 1942 of the phrase ‘Emil Emil’ which seemed to indicate that a nightfighter had now been brought close enough to the bomber for the latter to be picked up in the nightfighter’s own detector. Since German radar technique was obviously strong at wavelengths of 50-60 centimetres, and since such short wavelengths would be particularly suitable for nightfighter equipment because of the small overall dimensions, we decided to search particularly in this waveband. And since nightfighters were operating in the Scheldt Estuary, not more than one hundred miles from the Suffolk coast, there was a good chance that we could pick up the nightfighter radar transmissions on listening equipment ground-based in Suffolk. Fairly soon we heard transmissions on a wavelength of about 61 centimetres with a pulse repetition frequency of 3,000 per second, which seemed to come from moving sources. On 16th May 1942 we even attempted to intercept a nightfighter controlled from Domburg with one of our own Beaufighters controlled from Foreness. Tracks of both nightfighters were plotted by Fighter Command; but, thanks to the skill of both British and German controllers, the attempted combat ended in mutual frustration. The German aircraft refused to be tempted more than about 60 kilometres away from Domburg, so as to remain within range of its Giant Wurzburgs. Although it was reasonably certain that one form of Lichtenstein operated on 61 centimetres, it was possible that this was only used by the coastal nightfighters, where the Germans must know we could intercept the transmissions, and that a substantially different wavelength would be used further back. The next most important objective after the unravelling of the Kammhuber Line was to check whether the nightfighters associated with the Line also operated on 61 centimetres.[/I]” (The only way of obtaining this intelligence for certain was for an aircraft to act as bait to attract a nightfighter so that its radar transmissions could be measured. For this Jones needed a couple of Mosquitoes, which were fast enough to evade any nightfighter. To obtain these, he requested Air Marshall Harris and Air Vice Marshall Saunby personally, who agreed to let him have them, but…) “[I]Unfortunately the Mosquitoes were still not available some two months later, and it was decided to risk flying one of the Wellington aircraft, which were much slower, in front of a nightfighter in the hope that the operator who was listening for the nightfighter transmissions would be able to give enough warning for the Wellington to escape. Early in the morning of 3rd December a Wellington of No. 1474 (wireless-investigation) flight took off from an airfield near Huntingdon to accompany the raid that was directed against Frankfurt that night. Two hours or so later it was west of Mainz and was turning for home. The special radio operator was Pilot Officer Harold Jordan, who in peacetime had been a schoolteacher. Just after the turn for home he picked up weak signals on the expected wavelength and studied them for the next ten minutes as they increased in strength. He warned the rest of the crew what was happening and he drafted a coded signal saying that the signals had been picked up, confirming our suspicions as they were very probably coming from a nightfighter. The signal was dispatched by the wireless operator Flight Sergeant Bigoray. The nightfighter signals grew to a level which completely saturated Jordan’s receiver, and he warned the crew that an attack was imminent. It was almost immediately hit by cannon shells, and the pilot, Pilot Officer Paulton, tried to throw off the attack. The nightfighter attacked repeatedly, and the rear gunner fired about a thousand rounds back, until his turret was put out of action and he was hit in the shoulder. Jordan was hit in the arm, but he drafted a second message, and then was again hit in the jaw and one eye. As each attack developed, he tried to warn the pilot of the direction from which it was coming by continuing to observe its radar transmission. Ultimately the nightfighter broke off, leaving the Wellington barely flyable. The port engine throttle had been shot away, and the starboard throttle was jammed. The starboard aileron and both the air speed indicators were out of action. Four of the crew of six were badly wounded. Despite his wounds, Bigoray managed to send Jordan’s second message, repeating it again and again in the hope that someone might hear. It was in fact picked up in Britain and an acknowledgement made, but this was not heard in the Wellington because its receiver had been damaged. Bigoray went on repeating the message until a quarter to seven in the morning. As the aircraft approached the coast of England Paulton decided that it was too badly damaged to risk a crash landing, and that he would bring it down in the sea near the shore. Since he still did not know whether Jordan’s message had got through, and since Bigoray was so badly injured that he might not be able to get out of the aircraft before it sank, Paulton decided that he would fly inland and have Bigoray pushed out with his parachute with the vital information in case the aircraft and its remaining crew were lost in the sea. As Bigoray reached the rear escape hatch he remembered that he had not locked down his Morse key to provide the continuous note signal for ground direction finding stations to track the aircraft, so he painfully crawled back to fulfil his final duty. Paulton then flew back over the sea, and finally ditched in the sea some two hundred yards off Deal. The rubber dinghy could not be inflated since it had been holed many times and the crew stayed on the sinking bomber. Fortunately a few minutes later they were rescued. It had been an epic of cool observation, great gallantry and resourceful doggedness. For some days we did not know whether Jordan was going to lose his eye, but the surgeons managed to save it. He received an immediate Distinguished Service Order, the next thing to a Victoria Cross. Paulton was awarded the Distinguished Flying Cross, and Bigoray the Distinguished Flying Medal. The last gap in our understanding of the German night defences had been closed.[/I]” [CENTER]-----“----- [/CENTER] [I](Continued)[/I]


Another absolutely superb piece of work, Bill. Your research and writing are of the highest standards, and this whole thread has been a real joy to read. Waiting for you next installment is a bit like waiting for the next chapter in the Strand of the latest Sherlock Holmes mystery. Thanks for all your hard work! I am sure the other forum members will heartily agree.


Thank you very much Don. I must admit that this is turning into a labour of love. When I first started out I thought that about half a dozen posts would cover everything, but the deeper I dug the more I found. Most of the work/time involved is in verifying or dismissing these 'dicoveries', as there are a lot of inaccurate/wrong/misleading articles. As a simple example, in some articles on the Bruneval Raid, a photograph of a Giant Wurzburg is shown instead of the smaller Wurzburg A. Even now I cannot be certain that everything I have written is 100% accurate, but its the best I can do.


[QUOTE=Don Boyer;10095120][B]Another absolutely superb piece of work, Bill.[/B] Your research and writing are of the highest standards, and this whole thread has been a real joy to read. Waiting for you next installment is a bit like waiting for the next chapter in the Strand of the latest Sherlock Holmes mystery. Thanks for all your hard work! [B]I am sure the other forum members will heartily agree[/B].[/QUOTE] Agree 100% Don - a superb thread in all respects. Thanks for all your hard work on this topic Bill.


[quote=Scatari;10095184]Agree 100% Don - a superb thread in all respects. Thanks for all your hard work on this topic Bill.[/quote] And thank you too Tim.:)


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [U][B] (Airborne radar - Part 1b)[/B][/U] [[B]Note:[/B] Although the following is a slight diversion from the main topic of this thread, it follows on naturally from post #33, and it had an indirect influence on the further development of German airborne radar.] [U][B]Ground Grocer[/B][/U] The Telecommunications Research Establishment (T.R.E.) had been investigating the jamming of the Lichtenstein, and as soon as its frequency had been verified (3 December 1942), they designed and built a ground based jamming device known as ‘Ground Grocer’, the first of which came into operation at Dunwich on 26 April 1943. Originally it had been intended to use pulse jamming known as ‘Railings’, but too much research was needed, so simple noise jamming was adopted instead. The resulting installation consisted of a monitoring station equipped with a parabaloid antenna and receivers connected to a PPI (Plan Position Indicator), to display the direction from which the Lichtenstein signals were received, and two transmitters connected to a double paraboloid antenna which transmitted a 16 degree wide beam. The transmitter was remotely controlled from the monitoring site which, when a Lichtenstein signal was received, turned the transmitter and set its frequency to that of the received signal. It was estimated that Grocer would reduce the effective range of a Lichtenstein to 500 yards if the aircraft were as far away as 140 miles, at a height of 12,000 feet and within the beam of the paraboloid and flying towards the station. With the aircraft flying away from the station however, the effectiveness of Ground Grocer was greatly reduced. Thus Ground Grocer was mainly a cover for Allied bombers on their way home. In order not to give the enemy early warning of the approach of Allied bombers it was not switched on until the leading aircraft were within 30 miles of the enemy coast, which was probably its maximum effective range anyway. (It was estimated that effective cover against the Lichtenstein was at least up to, and over, the enemy coast.) Shortly after Ground Grocer was built, the Americans designed a very powerful transmitter valve called the Resnatron, and used it in a land based jamming station called ‘Tuba’, which was capable of delivering up to 60kW of continuous wave power at 500MHz (60cm wavelength). It first went into operation in June 1944, by which time the Lichtenstein radar for which it had been designed, had mainly been replaced by the new SN2 radar operating on a completely different wavelength. [[B]Note:[/B] There was an airborne jammer called ‘Grocer’, but it suffered from the same problem as all airborne signal transmissions. That is, their emissions could be, and were D/F’ed and targeted by nightfighters equipped with suitable radio receivers. For this reason, ground based jammers were developed, but unfortunately they were just not as effective, lacking the necessary power for their signals to penetrate deep into enemy territory. ‘Tuba’ would have been a great improvement but it arrived just too late.] [U]Attachments[/U]: 1. Ground Grocer receiver antenna. 2. Ground Grocer transmitter antennae. [ATTACH]138911[/ATTACH][ATTACH]138912[/ATTACH] [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar – A.I.- Part 2)[/I][/B][U][B] A.I. Radar SN2[/B][/U] (FuG 220) By 1943, the Lichtenstein B/C and C1 had been the nightfighter’s mainstay radar for nearly two years, but as the air war progressed and jamming increasingly reduced its effectiveness, the need for a new radar system became urgent. The Lichtenstein’s main shortcomings were its short range and narrow search beam. This constrained the nightfighters to Himmelbett control which selected their target for them and guided them to it until it was within range of their radar. But new tactics ('Zahme Sau') had been devised allowing them greater freedom to select their own targets. Telefunken's new SN2 was much better suited to 'Zahme Sau' tactics as it had a more powerful transmitter (2kW), double the range (6km), a wider search beam (110 degrees), and operated at a much longer wavelength (3.3 metres), which was at the time free from interference. This longer wavelength required a much larger antenna array which, from its appearance, the Germans called ‘stag antlers’. This consisted of four half-wave, vertically polarised dipoles with reflectors, arranged as two pairs. The dipoles were switched in pairs to produce both horizontal and vertical split beams. But this large array produced tremendous drag making the aircraft less manoeuvrable and slowing it by up to 50 k/h. After its introduction in 1943, the SN2 was found to have poor short range coverage, particularly under 400 metres. This was a major problem as nightfighters usually closed to within 200 metres for visual contact, before identifying the target and opening fire. To counter this, a ‘cut down’ version of the Lichtenstein B/C was fitted to cover this short range gap. The problem was finally resolved in the Spring of 1944 when a newer version with a lower minimum range introduced, allowing the B/C radar to be removed entirely. [[B]Note:[/B] In ‘Zauhme Sau’ (Tame sow) tactics, a squadron of nightfighters in line ahead, would be guided by ground control until they were flying parallel to the bomber stream. They would then be given the order to turn together towards the bombers, and each fighter would select a target with its radar.] [U]Attachment[/U]: 1. Bf 110 with SN2 FuG 220 and FuG 202. [ATTACH]138987[/ATTACH] [U][B]The wavelength puzzle[/B][/U] Following the introduction of SN2 in August 1943, the number of British bombers failing to return from night raids markedly increased, reaching a peak in the Spring of 1944, and it was suspected that a new type of radar was the reason. From Hinsley’s ‘British Intelligence in the Second World War’: “[I]The possibility that a new Lichtenstein was being introduced was raised in February 1944, after No. 80 Wing RAF had noticed a decline in Lichtenstein transmissions. By the beginning of March, No. 80 Wing had failed to find any unfamiliar signals, but the increase of bomber losses had made it painfully obvious that the enemy was using a new AI set[/I].” By 1944, daylight raids by American bombers with fighter escorts were causing the Germans such anxiety that, in desperation, nightfighters were often sent up against them. Several times they were photographed by the gunsight cameras of American fighters as they shot them down. Hinsley: “. . . [I]the Air Ministry’s Technical Intelligence Section noticed in the film of a combat between US fighter and a Ju88 night-fighter that the Ju88 was fitted with an aerial array similar to the rough sketch supplied by an agent in April; this had suggested a frequency of about 150 M/cs[/I].” (2.0 metres) From the photographs thus obtained, the new SN2 antennae were measured and analysed. From the estimated antenna size, it was deduced that they operated on a wavelength of about 2.3 metres, and the British were puzzled when no A.I. transmissions on or near this wavelength were detected. The correct wavelength was not discovered until July 1944, during which time the SN2 had operated for nine months without interference. [[B]Note:[/B] Although SN2 was undoubtedly successful, German sources tend to over estimate its effect, citing that night bombing raids diminished appreciably after its introduction. It is true the number of raids reduced, but this was the result of squadrons being withdrawn in the Spring of 1944 to participate instead in increased bombing operations over France as part of the preparations for the Normandy landings.] [U][B]The puzzle solved[/B][/U] At 04.25 hours on 13th July 1944, a Junkers 88 made a wheels-down landing on an emergency landing strip at Woodbridge, England. The pilot was completely lost and had apparently been flying on a reciprocal course from a beacon bearing. When he sighted Woodbridge he believed himself to be near Berlin, and being almost out of fuel, decided to land immediately. When he discovered his mistake, it was too late to do anything about it, and the aircraft was captured intact and undamaged. The Ju 88 was one of Germany’s latest night fighters and was fully equipped with up to date radar and radio. The radar was the latest SN2, from which its operating wavelength was measured, enabling ECM against it to begin within days. What had previously misled the British over its wavelength was that, to reduce the antenna physical size, loading coils had been connected in series with the antenna which reduced the resonant frequency of the half wave dipoles to the actual 3.3 metres of the radar. Also discovered fitted to the Ju88 was a new radio receiver, designated FuG 227 (Flensburg), for homing on to ‘Monica’ transmissions, (‘Monica’ was the Allied bombers tail warning radar), resulting in the use of ‘Monica’ being immediately discontinued. [U]Attachment[/U]: 1. The Woodbridge Ju88. 2. Later in RAF livery. (Flensburg antenna visible on each wing) [ATTACH]138988[/ATTACH][ATTACH]138989[/ATTACH] [U][B]A.I. SN2-R[/B][/U] (FuG 214) From an Intelligence report of PoW interrogations: “[I]Intruders over airfields are a considerable cause of disturbance, and it is very seldom that a night fighter crew can land on its base in peace. Added to this, there is always a sense of uneasiness amongst crews during sorties, with the result that their efficiency is much impaired[/I].” These intruder flights, mainly by Mosquito nightfighters flying with the main bomber stream, were making German aircrews nervous, having to look over their shoulder all the time. The Mosquitoes were fitted with the latest ‘Serrate’ which could detect Lichtenstein B/C, C1 and SN2 transmissions; and their ‘Perfectos’ IFF interrogator equipment could activate the nightfighter's IFF from up to 100 miles away, so they could be initially detected then pursued. Thus the hunters became the hunted! To counter this, a backwards looking radar attachment to the SN2 was devised to act as a tail warning. The antenna was mounted at the extreme end of the tail unit and consisted of a single horizontal dipole. No azimuth or elevation was measured, but the range of a following aircraft was shown on the azimuth display when the operator switched to rear view. The method employed was to search for contacts with the forward antenna and occasionally switching over to the rearward antenna to see if an enemy nightfighter was following. [U]Comment [/U] The fact that the tail warning radar was transmitted backwards must have made the nightfighter easier to detect from a longer range with the Mosquito’s ‘Serrate’. The Germans themselves had discovered how valuable these emissions were for detecting enemy aircraft, when their ‘Flensburg’ receiver, with which many nightfighters were equipped, was developed to detect emissions from British bomber’s ‘Monica’ tail warning radar. This same unfathomable reasoning also applied to their instructions to nightfighters to keep their IFF switched on, when they themselves had been interrogating British IFF for years to detect and locate the bombers. (See Freya Flamme). It’s no wonder the nightfighter crews were feeling uneasy when they were signalling their presence all over the sky to the very same intruders they were trying to avoid! [CENTER]-----“----- [/CENTER] [U][B]Later Developments[/B][/U] Once the wavelength of SN2 became known, it was successfully jammed by ECM and ‘Window’. From a PoW interrogation report: “[I]The PoW confirmed the effectiveness of Window countermeasures against the SN2 search equipment. Operators are now being told that Window is completely effective if the night fighter is at a range of more than 2,000 metres from a target aircraft; at ranges of less than 2,000 metres a skilled operator can distinguish between the Window blips and that of the bomber[/I].” An attempt was made to reduce the effects of jamming by mounting the SN2 antenna diagonally instead of vertically, but it is not known how effective this was. Another attempt was the ‘Morgenstern’ (morning star) antenna which comprised of a double set of two Yagi antenna arrays at 90° angles to each other, on a central axis. This had the advantage that it was just compact enough to fit into an extension to the nose of a Ju88, with just the tip of each element protruding. [U]Attachment[/U]: 1. SN2 diagonal antenna. 2. Experimental 'Morgenstern' antenna. [ATTACH]138990[/ATTACH][ATTACH]138991[/ATTACH] [U][B]A.I. SN3 [/B][/U](FuG 228) This was a longer range A.I. radar developed by Telefunken. Its 20 kW transmitter gave it a range of 250 to 8000 metres with a 120° wide search beam. It operated from 115 to 148 MHz (2.6 to 2.0 metres). Its antennae were similar to those of SN2 except for thicker dipoles. It is believed that about ten sets became operational, but nothing is known about their performance. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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Bill, I do not know why but I have only now discovered this gem of a thread. On a quick glance through what you have provided will give me hours of pleasure to delve into. I had always been under the impression that part of the German problem was their method of commissioning research. Each arm of the forces instructing scientists on their own account for their own purposes without any co-ordination. Hence they 're-invented the wheel' on more than one occasion. Can you advise re that as a possible slowing up of progress. While the UK looked on radar, initially at least, as a detection and early warning aid I also understood that the German navy was directing its research at providing a gunnery ranging set. Again the parameters of their objective did not focus on maximum range but accuracy within a modest range. Again, if you do not find such a trivial inquiry boring, your comments would be most welcome. Off to printing out your posts and read them properly. Thanks. Sandy McAuslan


[quote=Sandy McAuslan;10095686]I had always been under the impression that part of the German problem was their method of commissioning research. Each arm of the forces instructing scientists on their own account for their own purposes without any co-ordination. Hence they 're-invented the wheel' on more than one occasion. [/quote] Hello Sandy, This is certainly true, and the best example of this is that GEMA, Lorenz, Telefunken and Siemens were all developing a ground based panoramic radar, more or less at the same time, to fulfill the same purpose. The main problem, particularly in the early years of WW2, was perhaps a lack of direction. The radar companies were pretty much given a free hand to develop systems they thought the Luftwaffe needed, rather than be directed to satisfy a particular need. There was also a lot of friction between different departments of the Luftwaffe due to 'empire building' and power struggles. General Martini, as director of Lufwaffe signals was often ignored or overruled by Field Marshall Milch, the commander of Technical Office (which placed orders for equipment), who at one stage tried to gain control of Martini's department. At one time, Martini was even forbidden by Milch to talk to the wireless and radar companies about his requirements. So you can see that the atmosphere for an agreed and coordinated effort didn't exist, and progress suffered. [quote=Sandy McAuslan;10095686]I also understood that the German navy was directing its research at providing a gunnery ranging set. Again the parameters of their objective did not focus on maximum range but accuracy within a modest range. [/quote] From what I have have gleaned so far, it would appear that a range within 50 metres was considered good enough for gun laying, and the early versions of Seetakt were capable of this. My research into naval radar is at an early stage, so I might be able to give you a fuller reply later.


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar - A.I. - Part 3)[/I][/B][U][B] Neptun A.I. radar[/B][/U] Neptun was the code name of an early but unsuccessful experimental ASV radar, which was later developed as an Airborne Interception radar, retaining the same name. It was developed jointly by the FFO (Air Radio Research Institute) and Siemens in 1944. The resulting A.I radar was smaller than previous sets which enabled it to be fitted into a wide range of aircraft including single engine fighters. There are numerous variations of the ‘Neptun’ which are denoted by a model extension identifier, such as FuG 21x (J, J2 J3, GR, R1, R2, R3, V, VA, VR). This extension specifies features and combinations, such as: antenna type, rear warning, type of aircraft and transmitter power. Such variations are beyond the scope of this article. [U][B]Neptun 1[/B][/U] (FuG 216) This was mainly an experimental radar fitted to a limited number of Fw190s and Bf109s single engine fighters, and was used until March 1944. There were two versions: [U]FuG 216 V[/U], had a 1.2 kW, 125 MHz (1.3 metres) transmitter, with a 100° beam width, giving it a range of 3,500 metres. [U]FuG 216 R1[/U], had a 1 kW, 182 MHz (1.7 metres) transmitter, and was a tail warning device. [CENTER]-----“----- [/CENTER] [U][B]Neptun 2[/B][/U] (FuG 217) This operated in the frequency range 158 to 187 MHz (1.8 to 1.6 metres). Its 120 degree wide search beam gave it a range of 400 to 4,000 metres. The antennae array consisted of three vertical dipoles fitted above each wing and the upper part of the fuselage above and behind the canopy. [U]Tail warning attachment[/U] The rear pointing radar beam had a range of 3.5km, and was 35° wide and 90° high, directed 20 degrees downwards. Early models had vertical dipole (‘Spike’) antenna mounted under each wing; later models had horizontal antenna, aligned 20 degrees downwards to the rear, mounted above each wing. The transmit antenna was mounted on the right wing and the receive antenna on the left. [U]Attachment[/U]: 1. FW190 with FuG 217 forward and backward radar. [ATTACH]139025[/ATTACH] [CENTER] -----“----- [/CENTER] [U][B]Neptun 3 [/B][/U](FuG 218) This set, also developed by Siemens and FFO, was an improvement on the FuG 217. It was introduced in late 1944 as a replacement for the SN2 which the Allies had effectively jammed. It could operate on one of six frequencies, ranging from 158 to 187 MHz (1.9 to 1.6 metres), with a beam width of 120°, and a range of 120 to 5,000 meters. It was fitted to both single and twin engine fighters, including twin seat Me262s, but only experimentally. The single engine aircraft were fitted with the ‘spike’ antennae on the wings, while the twin engine fighters used the ‘Stag antlers’ fitted to the nose. The rear pointing tail warning attachment (Rückenwarnzusatz) could be fitted to either type of aircraft, with two horizontal dipoles installed on top of the fin. A later version (Neptun GR) with a much more powerful 30kW transmitter was introduced, with supposedly a 10,000 metre range. No further information about its performance can be found, and it is believed that only one was built. [U]Attachments[/U]: 1. Neptun 218 on Ju88, tail antenna just visible. 2. Neptun 218 on Me262 (FE612). 3. Neptun 218 on Me262 (FE610). 4. Tail warning antenna. [ATTACH]139026[/ATTACH][ATTACH]139027[/ATTACH][ATTACH]139028[/ATTACH][ATTACH]139029[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]Neptun 4 (Weilheim)[/B][/U] (FuG 219) This was a further development by Siemens of the FuG 218 GR. It had a transmitter power of 100kW at 172-188 MHz (1.9 to 1.7 metres), reputably giving it a range of about 15,000 metres; but again, no other information about its performance can be found. It is assumed that it used a similar antennae arrangement to the FuG 218 GR from which it was derived. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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Thanks Bill. Still engrossed reading to catch up. Cheers, Sandy McAuslan


[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [I][B](Airborne radar - Part 4)[/B][/I][U][B] Air to Surface Vessel (ASV) radar[/B][/U] The FW200 (Condor) was the only German aircraft capable of searching wide stretches of the North Atlantic for convoys at sea. To enable it to cover a greater area, particularly in less than perfect visibility, the need for a long range Air to Surface Vessel radar system arose. No less than four early ASV radars were developed and tested on various aircraft, but none were particularly suitable for the purpose. [I][B]Neptun[/B][/I] This was unsuccessful as an ASV radar, but was later developed as an Airborne Intercept radar. [I][B]Atlas [/B][/I] In July 1941, a 136 MHz ‘Atlas’ was installed and trialled in a Fw 200 but proved disappointing. [I][B]Rostock[/B][/I] At the same time as ‘Atlas’, a rival system ‘Rostock’, was being developed by GEMA. It operated at 120 MHz and had a 30km range. [I][B]Zaunkoenig [/B][/I] There was also a ‘Zaunkoenig’ (not to be confused with the acoustic torpedo of the same name), about which no information can be found other than a photograph of the antenna which look like a reduced version of the later ‘Hohentwiel’. [U]Attachment[/U]s: 1. Atlas antenna. 2. Rostock transmit antenna. 3. Rostock receive antenna. 4. Zaunkoenig on He111. [ATTACH]139126[/ATTACH][ATTACH]139127[/ATTACH][ATTACH]139128[/ATTACH][ATTACH]139129[/ATTACH] Of the above four, Rostock was the best of them, but implementation was slow and by November 1942 only five Fw 200 had been fitted with radar; four of which had the Rostock and another one operated a captured British ASV II set. In June 1941, an RAF bomber, equipped with ASV Mk II radar, made an emergency landing in France. Although the radar was damaged, the Germans deduced its function and operation, and after repair tested it. Their tests showed that it was better than the German ASV, and General Martini charged Lorenz with developing a similar system. The system that emerged was codenamed ‘Hohentwiel’; it was put into full production, entering service in 1943 and quickly became their main airborne surface search radar. [U][B]Hohentwiel ASV radar[/B][/U] (FuG 200) Operating on a range of wavelengths between 52 and 57 cm, with a PRF of 600Hz, Hohentwiel could detect a surfaced submarine at 10km, an aircraft at 25km, a ship (depending on size) at 70 km, and land at 150km. These are 'best case' figures for an aircraft flying at optimal height. It had separate antennae for transmit and receive. The transmit antenna was centrally mounted, pointing forward, while the two receive antennae were mounted either side, pointing outwards by 30 degrees, giving it a search beam width of about 120 degrees. Each antenna array consisted of sixteen horizontally polarised dipoles, mounted in four groups of four in a vertical stack. [[B]Note:[/B] Horizontal polarised antennae were preferred as they produce less ground clutter over water than vertical polarised antennae.] Because the antennae were fixed and could not be rotated, the searching aircraft had to be 'swung' left and right to detect objects lying abeam; and occasionally fly a complete circle to obtain maximum coverage. There was no 'split beam' feature, so the radio operator had to regularly switch manually the receiver arrays alternately to check for contacts and the direction in which they lay. Later, a motor-driven antenna switch was developed, and the received signal strength displayed on a CRT so the observer could gauge the target's bearing. [U]Attachments[/U]: 1. Hohentwiel on He111 2. Hohentwiel on Ju188 [ATTACH]139130[/ATTACH][ATTACH]139131[/ATTACH] [U][B]Other applications[/B][/U] Hohentwiel's powerful transmitter enabled the radar to be adapted for many other uses. It was used as a navigation aid over land, and formed the basis of several ship-borne systems for detection and navigation, as well as for ground based radar systems to detect low flying aircraft. One system was developed by Köthen as a mobile, land based radar for the Army, and was shown to have a range of about 30km for a single aircraft, and about 60km for formations. [U][B]Tiefentwiel[/B][/U] (FuMG 407) The Germans had a particular problem with low flying enemy aircraft, particularly Mosquitoes, crossing their coast undetected. A number of experiments were conducted to overcome this by placing various antenna arrays on tall masts. One experiment called ‘Tiefentwiel’, involved mounting the ‘Hohentwiel’ ASV radar high above the ground. Other than having a range of 30km, no other details of the antenna or its performance can be obtained. [[B]Note:[/B] The name 'Tiefentwiel' is a play on 'Hohentwiel'; 'Tief' meaning low and 'Hohe' meaning high.] In summary, Hohentwiel proved to be a very versatile system, being simultaneously operational in land, sea and air versions. [CENTER]-----"----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar – Part 5)[/I][/B][U][B] Centimetric airborne radar[/B][/U] Once the workings of the 9cm cavity magnetron became known to the Germans, their first task was to build a radar set like the British H2S from which it was recovered. The first sets they produced, codename ‘Rotterdam’, were simply H2S copies, although using German equivalents when original parts of recovered sets from crashed bombers were unavailable. The ‘Rotterdams’, because of their size and weight, could be fitted only into large aircraft. But the experience gained in building these enabled the Germans to redesign them, using German made components, into smaller and lighter sets which could be fitted into smaller aircraft. These smaller sets were codenamed ‘Berlin’, the first prototype of which was ready in early 1944. [U][B] [I]Berlin A[/I][/B][/U] (FuG 224) The first ten prototypes of the Telefunken built Berlin A were used for testing purposes. By May 1944, 35 sets had been built and were fitted almost exclusively to Ju88 G-6's. There is no reliable information as to how many were eventually built. The Berlin A had a designed maximum range of about 5,000 metres, but both it and the Rotterdam's minimum range was often as high as 2-3,000 metres. It is known that the PPI tubes used had a problem with a 'wandering' centre spot which may have contributed to the problem. However, steady technical improvements reduced this minimum range until it was acceptable. [U]Attachments[/U]: 1. Berlin A display unit. [ATTACH]139219[/ATTACH] [U][I][B]Berlin D[/B][/I][/U] – see ‘Bremen’ below. [[B]Note:[/B] No information can be found on ‘Berlin B’ or ‘Berlin C’ - if they ever existed as radar sets. They could possibly be the designation of Berlin units that were built into ground radar systems such as the ‘Kulmbach’ and ‘Marbach’, but that is just speculation.] [CENTER]-----“----- [/CENTER] [U][B]Airborne interception radar[/B][/U] The Berlin described above was, like H2S, an aid to navigation and ground mapping, so it is unclear how useful this type of radar was to the Luftwaffe at this stage of the war. A more pressing need was for a new nightfighter radar to replace their already heavily jammed airborne interception radars. To this end, a system was developed by Telefunken based on the Berlin A, and designated 'Berlin N'. [U][I][B]Berlin N1[/B][/I][/U] (FuG 240 N) The Berlin N1 had the high frequency components of a Berlin A combined with the display unit from the SN2 radar. Its weight of 180kg limited its use to Ju88’s. The 70cm parabolic antenna was fitted within a lightweight extension to the nose section, which eliminated the drag experienced by SN2 and Neptun equipped nightfighters, thus restoring the 50kph lost from their top speed. Its narrow search beam had the advantage that its maximum range was not so limited by noise from ground returns. The maximum range at low altitudes now being of the order of 2.5 times the height. But the disadvantage of the narrow beam was the difficulty of locating a target initially without constantly changing direction to 'sweep' the skies. This was overcome by making the antenna 'dish' steerable from within the cockpit by means of a joystick. By the end of the war, it is believed that only about 30 Berlin N1 sets had been built and 15 delivered; of which only three were operational in April 1945. [U]Attachment[/U]s: 1. Berlin N1 fitted to Ju88. 2. Ju88 with nose extension. [ATTACH]139222[/ATTACH] [ATTACH]139221[/ATTACH] There were other more advanced models (designated N2, N3 and N4) under various stages of development, but it is doubtful if any of these were completed. [U][I][B]Berlin N2 [/B][/I][/U] The Berlin N-2 model had a larger antenna and a 15kW transmitter, which increased its range to 9,000 metres; no other details of how it differed from the Berlin N1 can be found. [U][I][B]Berlin N3 [/B][/I][/U] The joystick driven antenna of previous models was replaced by one rotating at 400 rpm. The SN2 type of display unit was replaced by a 'C-Scope' which simplified the intercept. This was a moving spot indicator that had ‘cross hairs’ like a gunsight, with the target represented by a spot indicating its azimuth and elevation relative to the aircraft. The aircraft was steered to position the spot in the centre of the ‘cross hairs’; the target would then be straight ahead. It is unclear how the range of the target was indicated. [I][U][B]Berlin N4 [/B][/U][/I] This was a concept still in the research stage, which was to have been a development of the Berlin N3. The antenna was rotated in the horizontal plane under a housing on the top of the aircraft. The result would have been a 360 degree image of the sky around the aircraft, relative to its position, presented on a plan position indicator (PPI). It is unclear how the heights of targets thus located would have been indicated, or how enemy aircraft were to be distinguished from German aircraft. [CENTER]-----"----- [/CENTER] [U][B]Shorter wavelengths[/B][/U] Even before the first Berlin prototypes had been built, an H2X (3.2 cm) radar had been recovered from an Allied bomber that had crashed near Meddo in Holland. This radar was naturally given the codename ‘Meddo’. Immediately, radar receivers/detectors were developed (‘Naxos ZX’), capable of receiving these 3.2 cm transmissions, and were quickly deployed. Plans were also immediately made to build a ‘Meddo’ radar equivalent which was called 'Berlin D' initially, then later ‘Bremen’. [[B]Note:[/B] There is considerable confusion as to exactly what these two models of ‘Bremen’ were. I have chosen the most likely configurations, but it is by no means certain.] [I][U][B]Bremen[/B][/U][/I] (FuG244) or (Berlin D) This was basically a Berlin A with its 9 cm high frequency section replaced by a new 3 cm unit. Its designed range was from 200 to 5,000 metres with a search beam of 100° in azimuth and 20° in elevation. So far as is known, only one prototype was completed before the end of the war. [I][U][B]Bremen O[/B][/U][/I] (FuG245) It is possible that this was a 3 cm version of the Berlin N3. Whatever it was, it seems that again, only one prototype was under construction by May 1945. [CENTER]----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Airborne radar - Part 6)[/I][/B][U][B] Reflections and comment[/B][/U] The development and use of airborne interception radar (Lichtenstein and SN2) had followed an orderly and logical progression until about 1943. The discovery of that H2S radar seems to have disrupted this progression and thrown further development awry. [U][B]Centimetric radar[/B][/U] It was understandable that following the discovery of the H2S radar, the Germans would want to research and reproduce its technology. This they did, by making about 20 working copies in a remarkably short time, gaining experience in the field of centimetric technology in the process. It was after this that they seem to loose their way. What they did next was to allocate huge resources to develop the Berlin A, which was really only a repackaged H2S using German made components. This was still only a ground mapping radar; a radar which hitherto, the Luftwaffe hadn’t needed, and it is not obvious that they needed one now. The Berlin A appears to have been the solution to a problem which did not exist. The Lufwaffe’s real need was for a centimetric A.I. radar to replace their current heavily jammed systems. They needed to shoot down bombers, not improve their navigation! At the end of the war, the Berlin A was the only airborne centimetric radar operational in number. It is estimated that several hundred of these were operational, whereas there were only three nightfighters equipped with the Berlin N1. Had the resources to develop and build the Berlin A been allocated instead to the Berlin N1, then the Luftwaffe could possibly have had a centimetric A.I. radar operational a year earlier, when it was most needed. As it was, the Luftwaffe gained next to nothing in its operational effectiveness from over two years of resources, effort and money spent on developing centimetric radar. Yet again it seems as if radar development was being left to the electronics companies to produce equipment which they thought the Luftwaffe might need, instead of the Luftwaffe clearly stating their operational needs and telling the companies to come up with working solutions. A case of the tail wagging the dog? [U][B]The use of daytime fighters[/B][/U] (FW190, Bf109 and Me262) When the Neptun A.I. radar became operational in 1944, its small size enabled it to be fitted to fighters of this type for nightfighting. These fighters normally operated in daylight when they could use to advantage their greatest asset – their speed. For nightfighting, high speed was irrelevant. Was it thought that a radar equipped day fighter would perform better at night than its night counterpart? Were they so short of suitable aircraft (Me110, He111, Ju88 etc) that they needed to use fighters such as the Me262, the fastest fighter in the world, capable of 500+mph, to attack at night, bombers whose typical cruising speed was around 200mph? This is doubly puzzling as the reverse question could also be asked - Were they so short of daytime fighters that nightfighters had to be used for daylight attacks on U.S. bombers? This only led to the loss of experienced nightfighter crews. The answer to these rhetorical questions is ‘no’, because German aircraft production of all types, except the Bf110, reached a peak in 1944; there was no shortage of any of these types of aircraft. So far as it can be established, none of the Allies equipped their day fighters with radar. The rationale for the Germans doing this is difficult to discern. It seems to have been a case of “If it’s possible - then it will be done”, without regard to the suitability of the aircraft or the operational necessity of such a marriage. [CENTER]-----"----- [/CENTER] [U][B]Against the odds[/B][/U] In case the impression has been given that jamming and other ECM had rendered German A.I. ineffective, the last word goes to the airmen of the Luftwaffe, who just got on with their job with the equipment they had to the best of their ability. Some had remarkable ability, achieving extraordinary results against the odds. In the Imperial War Museum, there exists the port tail fin of the Bf110G nightfighter flown by Major Heinz Wolfgang Schnaufer. On it there are marked 121 victories, making him the leading nightfighter pilot of WW2. He achieved this in the space of less than three years. On 21 February 1945 he shot down nine Lancasters in one day alone; two in the morning, and that same night, another seven fell victim in only 19 minutes. He was just 23 years old at the time. He died in a road accident in 1950 aged 28 years. [U]Attachments[/U]: 1. Schnaufer’s Bf110 tail fin. 2. Close up of the fin. 3. Heinz Wolfgang Schnaufer, with Knights Cross, oak leaves, swords and diamonds. [ATTACH]139310[/ATTACH] [ATTACH]139311[/ATTACH] [ATTACH]139312[/ATTACH] [CENTER]-----“----- [/CENTER]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I] (Naval radar - Part 1)[/I][/B][U][B] Introduction[/B][/U] The radar company GEMA developed its first radar system to detect the presence of ships at sea. Following a successful demonstration, in which an aircraft was fortuitously detected, it was developed into two distinct systems. The one to detect aircraft became the Luftwaffe’s ‘Freya’, and the Kriegsmarine’s ship detector was named ‘Seetakt’. [U][B]Terminology and designation[/B][/U] Following their adoption of Seetakt, the Kriegsmarine found applications for many types of Luftwaffe radar as they became available. They can be categorised, according to the use to which they were put, into four distinct types, namely: [I][B]Seetakt[/B][/I] for ship detection; [I][B]Flugmeldung[/B][/I] for aircraft warning; [I][B]Flakziel[/B][/I] for Flak direction; [I][B]Seeart[/B][/I] for coastal battery direction. All of these, except Seeart, could be either ship borne or land based, or both. The land based radars were mainly of the type used by the Luftwaffe e.g. Freya, Wurzburg etc. Although many naval radars were identical to Luftwaffe radars, they acquired a different designation for naval use, namely FuMO (FunkMessOrtung – location measuring radio). [CENTER]-----“----- [U][B]Land based radars[/B][/U] [/CENTER] Naval land based radars were deployed along the Atlantic, Channel and North Sea coastlines, and were used mainly to detect approaching enemy ships and aircraft. Others were used to direct flak and coastal battery firing, and others to track shipping, especially around the minefields in the Heligoland Bight. The following land based radars have been roughly divided into their main functions, but some types had multiple roles and appear in more than one category. [U][B]Ship detection[/B][/U] (Seetakt - Sea tactical) These types of radar were used for detecting surface vessels at sea. This was the name given to GEMA’s first naval radar which described its purpose. Subsequently, other models of radar which fulfilled the same purpose, are confusingly also described as Seetakt. In the following narrative, Seetakt is used only to describe the GEMA original and its derivatives. There are several version of the basic Seetakt, their designations being FuMO 1-5, all used as 'coastwatchers' for enemy ships. They were usually named after French coastal cities, e.g. Calais, Dunkirk, Boulogne etc. [I][B]FuMO 1[/B][/I] (Calais A) Its 6.2 x 2.5m antenna consisted of 2 rows of eight full wave vertical dipoles. Its wavelength was 82cm and its range depended on the height it was installed above sea level, but typically was about 15-20km. This short maximum range was due to distant targets being obscured by 'clutter' from the sea. It was later discovered that this ‘clutter' was less pronounced with horizontally polarised dipoles. [I][B]FuMO 2[/B][/I] (Calais B) This was a modification of the FuMO 1 with a more powerful transmitter and a larger antenna consisting of four rows of sixteen vertical dipoles. Although its range was similar to the FuMO 1, it was more accurate. [I][B]FuMO 3[/B][/I] (Zerstorersaule) This was a further development with a rotatable antenna separate from the operations cabin. The antenna consisted of four rows of ten vertical dipoles and had a range of 7-12km. There was a larger version with sixteen dipoles in each row. [U]Attachment[/U]: 1. FuMO 3 Zerstorersaule large. [ATTACH]139698[/ATTACH] [I][B]FuMO 4[/B][/I] (Dunkirchen) The 6.5 x 3.2m antenna had eight rows of sixteen horizontal dipoles. The horizontal dipoles increased the range to 20-30km by reducing the sea 'clutter'. [U]Attachment[/U]: 1. FuMO 4 Dunkirchen. [ATTACH]139699[/ATTACH] [I][B]FuMO 5[/B][/I] (Boulogne) From the antenna size, 6.5 x 5m, this appears to have been a larger version of the FuMO 4, with twelve rows of sixteen dipoles. It had a more powerful transmitter (150kW) increasing the range to 30-40 km. [U]Attachment[/U]: 1. FuMO 5 Boulogne. [ATTACH]139700[/ATTACH] [I][B]FuMO 11[/B][/I] (Renner 1) This centimetric radar used a 3m solid parabolic reflector similar to a small Wurzburg. Its 15kW transmitter gave it a range of 20-70km. It was basically a Seetakt with the high frequency part replaced with a 9cm ‘Berlin’ unit, keeping the rest of the Seetakt electronics. [U]Attachment[/U]: 1. Renner 1. [ATTACH]139701[/ATTACH] [I][B]FuMO 12-13[/B][/I] (Renner 2-3) This was a development of the Renner 1 with PPI, and a range of 30-40km. The Renner suffered reliability problems and wasn’t produced in quantity. [I][B]FuMO 15[/B][/I] (Scheer) Giant Wurzburg with ‘Berlin’ 9cm, range 90km. [I][B]FuMG 40L[/B][/I] (Kurmark) The following is unverified as this radar doesn’t seem to have a naval FuMO designation: “[I]The Lorenz Kurmark, with its power increased to 50 kW, had a range of up to 40 km and . . . . also existed in a Seetakt version, in which function it was used by naval coastal batteries to locate shipping targets[/I].” [I][B]FuMO 51[/B][/I] (Mammut G) This antenna array was a matrix of multiple Seetakt antennae measuring 19.6m x 13.8m, mounted on three pylons. It operated on the usual Seetakt 82cm wavelength, and its range was about 40-60km for surface vessels and 200 km for aircraft. [[B]Note:[/B] Very little reliable information about this large structure can be obtained. The only thing upon which most accounts agree is its size. Most are content to call it a naval version of the Luftwaffe’s FuMG 401 Mammut and assume it also consisted of multiple Freyas. This seems unlikely as its dimensions do not match; but they do match with multiple Seetakt antennae. Also, the Kriegsmarine already used the Mammut C (FuMO 52) to detect aircraft, so why would they want a less capable smaller version? It seems more likely that they would want to increase the range at which shipping could be detected, for which multiple Seetakts would be more suitable.] [U]Attachmen[/U]t: 1. FuMO 51 Mammut G. [ATTACH]139702[/ATTACH] [I][B]FuMO 214[/B][/I] (Giant Wurzburg) The Kriegsmarine used this both in the Seetakt and the Seeart roles, the latter to direct the fire from coastal batteries. [U] Attachment[/U]: 1. FuMO 214. [ATTACH]139706[/ATTACH] [I][B]FuMO 215[/B][/I] (SeeRiese) This seems to be an improved FuMO 214 Giant Wurzburg with its range increased to 80km. [CENTER]-----“----- [/CENTER] [U][B]Aircraft warning[/B][/U] (Flugmeldung - Flum) Many types of radar were used for this purpose. All except the Freiburg, were Luftwaffe models with naval designations. As these have been described before, they are just listed here for reference with their Luftwaffe designation in parenthesis. [I][B]FuMO 52[/B][/I] (FuMG 401 - Mammut C) [I][B]FuMO 64[/B][/I] (Hohentwiel L) An adaption of the Hohentwiel ASV radar for seacoast defence. [I][B]FuMO 221[/B][/I] (FuMG 64 - Mannheim) The Mannheim had a 3m dish like the Wurzburg but was about twice as accurate due to the indication of deviation of the target on gauges rather than just oscilloscopes. A later model with track locking was developed called the Mannheim K. [U]Attachment[/U]: 1. FuMO 221 Mannheim [ATTACH]139707[/ATTACH] [[B]Note:[/B] A fuller description can be found under its Luftwaffe designation of FuMG 64.] [I][B]FuMO 301-303[/B][/I] (FuMG 39-41) Freya It is unclear exactly which models of Freya are referred to here, but the most likely are the basic Freya, the Freya A/N, and the Freya Freiburg. [I][B]FuMO 311-318[/B][/I] (Freiburg I – wavelength 2.0-2.5 metres) Based on the GEMA Freya, these were was produced by AEG and introduced by the Kriegsmarine in 1941. They operated in the 2.2 metre band with a 10kW transmitter. They were used by naval flak batteries to locate aircraft up to 120 km out to sea. Other versions in the 311-318 range reflected the use of different wavelengths within the same band. [U]Attachment[/U]: 1. FuMO 312 Freiburg. [ATTACH]139708[/ATTACH] [I][B]FuMO 321-328[/B][/I] (Freiburg II – wavelength 1.4-1.6 metres) These were similar to the FuMO 311-318 but operated in the 1.5 metre band. [I][B]FuMO 331[/B][/I] (FuMG 402 - Wassermann M) [I][B]FuMO 371[/B][/I] (FuMG 403 – Jagdschloss) [CENTER]-----"----- [/CENTER] [U][B]Flak direction[/B][/U] (Flakziel) Except for the FuMO 201 Flakleit, these were Luftwaffe models used by the Kriegsmarine. [I][B]FuMO 201[/B][/I] (Flakleit) This radar was built for the Kriegsmarine by GEMA. It used the 80cm Seetakt wavelength and was capable of directing fire on surface and air targets. It was mounted on a rotatable, underground, armoured optical rangefinder for shore batteries. Flakleit used two ‘owls ears’ attachments to the Seetakt antenna. One ‘ear’ was for transmission and the other was for receiving. Lobe switching was used on both the vertical and the horizontal axis providing full blind fire capability against aircraft as well as surface targets. It is assumed that the Seetakt antenna was used for initial target acquisition, and the ‘ears’ for Flak direction. Some later Flakleit sets had only one ‘ear’ antenna attachment; presumably the Seetakt provided the bearing and the 'ear' the height. [U]Attachment[/U]: 1. FuMO 201 Flakleit. [ATTACH]139703[/ATTACH] [I][B]FuMO 211-213[/B][/I] (FuMG 62 - Würzburg A,C,D) The FuMO 211 Würzburg was introduced as early as 1940 to direct flak artillery. It was able to locate aerial targets up to 30 km. [I][B]FuMO 215[/B][/I] (See Riese) Similar to the FuMO 214 Giant Wurzburg, but with a slightly longer range of 80 km. [I][B]FuMO 221[/B][/I] (Mannheim) See above. [CENTER]-----"----- [/CENTER] [U][B]Coastal battery direction[/B][/U] (Seeart - Sea artillery) Used to direct the fire of naval coastal batteries. [I][B]FuMO 111 [/B][/I](Barbara) 9cm ‘Picture’ scanning radar. This was an experimental, modified 9cm FuMO 15 Giant Wurzburg, whose sharply focussed beam could scan targets line by line to produce an image. In early 1945, at a test in Felsterhaken, the lowering of a boat from a ship was observed on a screen. [I][B]FuMO 214[/B][/I] (Giant Wurzburg) The FuMO 214 Würzburg Riese was the naval version of the popular Luftwaffe radar. Produced by Telefunken it was able to locate accurately naval targets out to 60 km. It was also used in the Seetakt role. [I][B]FuMO 215[/B][/I] (See Riese) Similar to FuMO 214 Giant Wurzburg but with range extended to 80 km. [CENTER]-----“----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I] (Naval radar - Part 2)[/I][/B][CENTER][U][B] Shipborne radars[/B][/U] [/CENTER] Fundamentally, the early shipborne radar models were little different from the land based 82cm Seetakt model upon which they were based, being used mainly for ship detection and range finding. They differed mainly in the power of their transmitters, and the type, size and position in which their antennae were installed. The later models had better electronics giving more accurate positioning and reliability, and could be used for Flak direction. The [I]Graf Spee[/I] is generally credited with being the first warship equipped with radar when a FuMO 22 Seetakt was fitted to her in 1939. [[B]Note:[/B] Good photographs of shipborne radar antenna are difficult to find, as they were mounted high up, and out of necessity, taken from a distance.] [U][B]Seetakt radar[/B][/U] [I][B]FuMO 21 [/B][/I] Fitted on destroyers and light cruisers ([I]Koln, Nurnberg[/I]) This and FuMO 22 and 23 had similar characteristics (transmitter 8kW, range about 15km) with a 4m x 2m antenna array. It was first tested in the cruiser [I]Nurnberg[/I]. [I][B]FuMO 22 [/B][/I] Fitted on major warships ([I]Graf Spee, Lutzow, Scharnhorst, Gneisenau, Blucher, Hipper[/I]) The antenna was a 6m x 2m mattress, except for the [I]Graf Spee[/I]’s which was only 1.8m x 0.8m. [I][B]FuMO 23 [/B][/I] Fitted on battleships ([I]Bismarck, Tirpitz[/I]) The antenna consisted of 4 rows of 10 dipoles and was mounted on the fire-control director. [[B]Note:[/B] These first three types differed mainly in the type and position of the antenna. Being based on the original Seetakt land based model, they were unsuited to the harsher shipborne environment, being susceptible to corrosion, shock and vibration, (particularly the valves) and proved unreliable. Later models had new transmitter valves which had a much greater resistance to shock, particularly when the main armament was fired.] [I][B]FuMO 24[/B][/I] (power 8kW, range 15-20 km) Fitted on destroyers. This was the first of the improved radars designed to be mounted on a destroyer. Peak power was 8kW and antenna dimensions 6m x 2m. In 1944, many FuMO 24 were upgraded to FuMO 32 by the replacement of their transmitters with 125kW units. [I][B]FuMO 25[/B][/I] (power 14kW, range 15-25 km) Fitted on major warships and cruisers ([I]Hipper, Prinz Eugen, Nurnburg, Emden, Leipzig[/I]) Mast antenna, with a 6m x 2m or 4m x 2m antenna, otherwise equivalent to FuMO 24. Many were upgraded to FuMO 33 in 1944. [I][B]FuMO 26[/B][/I] (power 14kW, range 15-25 km) Fitted on major warships ([I]Tirpitz, Prinz Eugen[/I]) Radar for fire control directors, using a new horizontally-polarized 6.5m x 3.2m antenna, giving it a range of 20-25km. It had both horizontal and vertical lobe switching which enabled it also to be used for Flak direction. Some were upgraded to FuMO 34 (125kW) in 1944, increasing the range to 40-50 km. [I][B]FuMO 27[/B][/I] (power 15kW, range 15-25 km) Fitted on battleships and cruisers with a 4m x 2m antenna ([I]Scheer, Scharnhorst, Gneiseanu, Tirpitz, Hipper, Blucher, Prinz Eugen[/I]). It was superseded by the FuMO 26. [I][B]FuMO 28[/B][/I] Fitted to torpedo boats with two fixed 2.6m x 2.4m antennae. [I][B]FuMO 32-34[/B][/I] In 1944, FuMO 24, 25, and 26 were upgraded with the more powerful 125kW transmitters and designated FuMO 32, 33, and 34 respectively. [CENTER]-----“----- [/CENTER] [U][B]Other radar types[/B][/U] [I][B]FuMO 41[/B][/I] (Segler) This was the shipborne version of GEMA’s 9cm FuMO 11 Renner. Its 15kW transmitter gave it a range of 20-30 km. A 3cm Segler D was also under development. [I][B]FuMO 62[/B][/I] (Hohentwiel S) This was a development for torpedo boats from the 55cm Hohentwiel airborne ASV radar, with a 1.5 x 1.6m rotating antenna, and a range of 12-20 km. [I][B]FuMO 63[/B][/I] (Hohentwiel K) Hohentwiel K became available at the beginning of 1944 for large torpedo-boats, destroyers and cruisers. Systems were fitted to the foremast and mainmast and had rotating 2.4 x 2.0 metre antennae. [I][B]FuMO 71[/B][/I] (Lichtenstein B/C) As the Luftwaffe’s Lichtenstein B/C A.I. radar was being replaced by SN2, they were modified for naval use on smaller torpedo boats. [I][B]FuMO 72[/B][/I] (Lichtenstein B/C) This was a FuMO 71 with a rotating antenna and PPI display unit. [I][B]FuMO 81[/B][/I] (Berlin S) Berlin S was Telefunken’s Berlin A, modified for the Kriegsmarine to give an all-round panoramic view on a PPI display. Although it was originally designed for smaller ships, in 1945 one was installed aboard [I]Prinz Eugen[/I]. [I][B] FuMO 202[/B][/I] (Flakleit) This was the shipborne version of the land based FuMO 201 Flakleit radar. It used the 80cm Seetakt wavelength and was capable of directing fire on surface and air targets. Flakleit used the "owls ears" antennae as seen on the [I]Prinz Eugen[/I] in 1942 and early 1943. These 'owls ears' antennae were to determine elevation; with one ‘ear’ for transmission and the other for receiving. Lobe switching was used on both the vertical and the horizontal axis providing full blind fire capability against aircraft. In 1943 it was replaced by the FuMO 26. [I][B]FuMO 231[/B][/I] (Euklid) This was to have been Telefunken’s Flak directing radar for destroyers. It was a smaller and more advanced version of the FuMO 221 Manheim K, from which it was derived, with a 1.5m dish antenna and with 27cm wavelength. When research into centimetric radar came under the authority of the AGR, Euklid was delayed, but later continued when the Kriegsmarine had the Telefunken engineers continue under their authority. Development was almost completed and ready for sea trials when the war ended. [CENTER]-----“----- [/CENTER] [U][B]Major warship's radar equipment[/B][/U] Although all major warships had several radars, they were often of different types, and not all were present at the same time, some being replaced by later models. Some ships had multiples of the same radar models; this is noted where known. The following lists the radar types fitted to each ship throughout their wartime service, though not in chronological order. [[B]Note:[/B] Although FuMO 24-26 were replaced by FuMO 32-34, no mention of the latter being fitted can be found, although it is known that many of the former were upgraded with the new 125kW transmitters.] [I][B]Bismarck [/B][/I] 3 x FuMO 23. It is surprising that [I]Bismarck[/I] was fitted with this early unreliable radar, as the newer FuMO 27 had been available for a year and already fitted to the [I]Prinz Eugen[/I]. The result was that after firing her guns at Norfolk in the Denmark Strait, her two forward FuMO 23s became inoperable; which is why [I]Prinz Eugen[/I] then had to take the lead. [U]Attachment[/U]: 1. [I]Bismarck[/I]'s FuMO 23 antenna. (The photo caption doesn't make it clear if this is actually of the [I]Bismarck[/I], or of the antenna type fitted to the [I]Bismarck[/I].) [ATTACH]139738[/ATTACH] [I][B]Tirpitz[/B][/I] FuMO 23; 3 x FuMO 26; FuMO 27; FuMO 63 (Hohentweil); FuMO 81 (Berlin S); FuMO 212 or 213 (Wurzburg C or D). [I][B]Graf Spee[/B][/I] FuMO 22. In some photographs of the [I]Graf Spee[/I], her Seetakt antenna is shown covered with a canvass sheet, giving it the appearance of a mattress, which may be the origin of the name for this type of antenna. [I][B]Scharnhorst[/B][/I] 2 x FuMO 22; FuMO 27. [I][B]Prinz Eugen[/B][/I] FuMO 25; FuMO 26; 2 x FuMO 27; FuMO 81 (Berlin S); FuMO 202 (Flakleit). [I][B]Lutzow[/B][/I] FuMO 22. [I][B]Hipper[/B][/I] FuMO 22; FuMO 25; FuMO 27. [I][B]Gneisenau[/B][/I] 2 x FuMO 22; FuMO 27. [I][B]Scheer[/B][/I] FuMO 22; 2 x FuMO 27. [I][B]Blucher[/B][/I] FuMO 22; FuMO 27. [CENTER]-----“----- [/CENTER] [U][B] Light Cruisers[/B][/U] [I][B]Koln[/B][/I] FuMO 21; FuMO 25. [I][B]Nurnberg[/B][/I] FuMO 21; FuMO 25; FuMO 63 (Hohentwiel K). [I][B]Leipzig[/B][/I] FuMO 25. [I][B]Emden[/B][/I] FuMO 25. [CENTER]-----“----- [/CENTER] [U][B]Destroyers and smaller[/B][/U] Destroyers were fitted with the FuMO 21 (Seetakt) until superseded by the FuMO 25 (Seetakt) in 1943. Some also received a FuMO 63 (Hohentwiel K) in 1944. Originally none of the earlier torpedo boats were equipped with radar but some of the smaller types received the FuMO 28 (Seetakt) and later a FuMO 62/63 (Hohentwiel S/K) in 1944. The larger torpedo boats received the FuMO 21. Even the old pre-dreadnoughts, [I]Schleisen[/I] and [I]Schleswig-Holstein[/I] had FuMO 25 sets at the end of the war. S-Boats working in the English Channel at night also needed radar, but all current naval types were too big. However, as the Luftwaffe upgraded their A.I. Lichtenstein B/C radar sets, the old ones was taken by the Kriegsmarine and mounted with a fixed array on an S-Boat and designated FuMO 71. A rotating array was later developed for it and designated the FuMO 72. But the antenna gave the S-Boat too high a silhouette and they didn’t become operational. [CENTER]-----"----- [/CENTER] [I](Continued)[/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [I][B](Naval radar - Part 3)[/B][/I] [CENTER][U][B]U-Boat radar[/B][/U] [/CENTER] Although equipping U-Boats with radar was contemplated in 1939, it wasn’t until the following year that an order was placed with GEMA for a radar small enough to fit inside a U-Boat. GEMA modified their early Seetakt radar accordingly, and a few experimental sets were delivered later the same year for testing and fitted to type IXC boats. The final models, designated FuMO 29, were delivered in 1941 and fitted to the same type of U-Boats. [U][B] Seetakt[/B][/U] [I][B]FuMO 29[/B][/I] (Seetakt) Its 10kW transmitter, operating on the usual Seetakt wavelength of 82cm, produced a 60 degree beam, giving a range of about 7.5km against surface vessels and 15km against aircraft at 500 metres altitude. The antenna array was mounted on the curved front of the U-Boat’s conning tower, and consisted of two rows of six vertical dipoles. Its main disadvantage was that this allowed searches only in the forward direction. Consequently, the boat had to make a complete turn to search the whole horizon. In 1942 the antenna was replaced by a 1.4m x 1m array with wire mesh reflector, fitted on a retractable, rotating mast inside the conning tower. [U]Attachment[/U]: 1. FuMO 29 antenna on conning tower. [ATTACH]139789[/ATTACH] [I][B]FuMO 30 [/B][/I] (Seetakt) Early in 1943, the FuMO 30 was introduced to replace the FuMO 29. Its range was slightly improved to 8.0km. Its antenna, consisting of two rows of four vertical, half wave dipoles with a wire mesh reflector, was mounted on a rotatable shaft on the port side of the conning tower, and manually rotated by a hand wheel in the radio room. The antenna was raised by a pneumatic piston, and lowered into a slot when not in use. It was used until March 1944, when it was replaced by the FuMO 61 Hohentwiel U. [U]Attachments[/U]: 1. FuMO 30 antenna on U995. 2. FuMO 30 on U505. [ATTACH]139790[/ATTACH] [ATTACH]139791[/ATTACH] [CENTER]-----“----- [/CENTER] [U][B]Hohentwiel[/B][/U] In 1943 Lorenz was requested to adapt their Luftwaffe ASV Hohentwiel radar for naval use. Its small size made it particularly suitable for U-Boats, enabling the electronic equipment to be located in, and operated from, the radio room. [I][B] FuMO 61[/B][/I] (Hohentwiel U) The FuMO 61 antenna array was small at 1.4m x 1.0m with four rows of six half wave dipoles with a wire mesh reflector operating at a wavelength of 54cm. Its 30 kW transmitter gave it a range of 8-10km for ships and 15-20km for aircraft at 200 metres altitude. Its small antenna was mounted on the top of a rotatable shaft located on the port side of the bridge. It was lowered into a dedicated recess in the conning tower casing, and raised by means of a pneumatic piston. The shaft was connected to the radio room with a flexible shaft, and the operator could rotate the antenna manually by turning a hand wheel. The display unit was a simple oscilloscope with a vertical trace indicating the distance to target. As this version of Hohentwiel didn’t use lobe switching, the bearing was determined by rotating the antenna to get a maximum symmetrical return signal on the screen, similar to the A.I. Lichtenstein. [I][B]FuMO 65[/B][/I] (Hohentwiel U1) This was basically the same radar as the FuMO 61 Hohentwiel U, but with a rotating antenna and the operator’s display replaced by a Plan Position Indicator. Its wavelength could now be selected from 52cm to 58cm. It was installed in only a few Type XXI U-Boats, and considered especially useful for navigation in coastal waters. Although is was reliable, it was little used as passive radar detectors were preferred in order to reduce emissions and keep as low a profile as possible. [CENTER]-----“----- [/CENTER] [U][B]Berlin centimetric[/B][/U] [I][B] FuMO 83[/B][/I] (Berlin UI) Built by Telefunken, this was the first centimetric radar to be fitted to a U-Boat. It used the ubiquitous ‘Berlin’ 9cm transmitter and receiver and PPI display unit. The antenna was mounted in a watertight plastic sphere, which was fitted on top of a retractable, rotating mast. Its range was about 20-30km, and its PPI display, according to one U-Boat commander, gave a view as "from a balloon 200 metres above the boat". [I][B]FuMO 84[/B][/I] (Berlin UII) This was a late development that was tested but didn’t become operational before the war ended. It was basically the same as the FuMO 83 but with a different antenna. This time, the antenna itself rotated within the watertight plastic dome, and was mounted on the Schnorkel head. This extra height had the double advantage of improving the range and gave the radar the ability to be used while submerged. [CENTER]-----“----- [/CENTER] [U][I][B]FuMO 391[/B][/I][/U] (Lessing) This was an omni-directional aircraft warning radar developed for type XXI U-Boats by GEMA. It transmitted a signal in all direction simultaneously. It was mainly intended to warn of a surprise attack while snorkelling. It used a modified and miniaturized version of the Freya transmitter (125 kW, 2.4 metres), and a fixed position single dipole antenna mounted on the schnorkel head. It had a maximum range of about 30km for an aircraft at 2,000m, but provided no bearing or elevation – it was only an early warning device to give the U-Boat up to five minutes warning of approaching aircraft. It was intended for type XXI U-Boats, and its advantage was the ability to operate while snorkelling, but at a slightly reduced range. It appears that only one experimental model was built in 1944. [CENTER]-----“----- [/CENTER] [U][I][B]FuMO ???[/B][/I][/U] (Ballspiel) Ballspiel was a gunnery radar for U-boats. It was a development of FuMO 83 Berlin UI. It normally had a range of 25 km, but only 8km maximum was used. It had an azimuth accuracy of about 1 degree and a range accuracy of 500 meters. It is known that Ballspiel was used operationally, but nothing can be found about its effectiveness or its designation. [CENTER]-----“----- [/CENTER] [U][B]Summary[/B][/U] The adaptation of existing radar systems (e.g. Seetakt) for naval use seems to have been the general rule rather than the exception. While this had its advantages, it did mean that naval vessels received their radar later than other services, possibly loosing operation effectiveness in the interim period. However, generally speaking, radar of any type fitted to U-Boats was not popular among their commanders. The early Seetak models (FuMO 29/30) were prone to frequent breakdowns, and the FuMO 29 with its huge 300 degree ‘blind spot’ necessitating frequent 360 degree turns, convinced them that it was more trouble than it was worth. Also there was the fear that high power transmissions from their own radar would be detected by Allied aircraft and homed into. Considering the scare when 'phantom' emissions from their own radar detector Metox were suspected for a rise in unexplained U-Boat losses, it is entirely understandable that their radar, broadcasting kilowatts of emissions, frequently wasn’t switched on. Instead, their preference was for passive radar detectors tuned to enemy aircraft radar transmissions, as an aircraft with its radar turned on could be detected from a much greater distance with the U-Boat’s radar detector than with their own radar. [CENTER]-----“----- [/CENTER] [I](Continued) [/I]
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[CENTER][U][B]The Development of German Radar in WW2[/B][/U] [/CENTER] [B][I](Naval radar – Part 4)[/I][/B][CENTER][U][B]Naval radar reference[/B][/U] [/CENTER] To round off this series on naval radar, I thought it might be useful to provide a reference list of all naval radars previously mentioned, plus a few late discoveries. They are presented in numerical order and fall naturally into the four categories. [I] [U]Ship detection and fire control[/U][/I] (Seetakt) - FuMO 1 to 100 [U][I]Coastal battery direction[/I][/U] (Seeart) - FuMO 101 to 200 [U][I]Flak direction[/I][/U] (Flakziel) - FuMO 201 to 300 [U][I]Aircraft warning[/I][/U] (Flugmeldung) - FuMO 301 to 400 [CENTER]-----“----- [/CENTER] [U][B]Ship detection and fire control[/B][/U] (Seetakt) [[B]Note:[/B] Many of these were also used for aircraft warning (Flugmeldung).] [U]Land based[/U] FuMO 1 Calais A FuMO 2 Calais B FuMO 3 Zerstörer säule FuMO 4 Dunkirchen FuMO 5 Boulogne [U]Centimetric[/U] (Land based) FuMO 11 Renner 1 FuMO 12 Renner 2 FuMO 13 Renner 3 FuMO 14 Berlin L FuMO 15 Scheer (9cm Giant Wurzburg) [U]Ship borne[/U] FuMO 21 (destroyers and light cruisers) FuMO 22 (capital ships and cruisers) FuMO 23 (capital ships) FuMO 24 (destroyers) FuMO 25 (capital ships and cruisers) FuMO 26 (capital ships) FuMO 27 (capital ships and cruisers) FuMO 29 Seetakt (U-Boats) FuMO 30 Seetakt (U-Boats) [U]Shipborne[/U] FuMO 31 ??? FuMO 32 upgraded FuMO 24 FuMO 33 upgraded FuMO 25 FuMO 34 upgraded FuMO 26 [U]Land based[/U] FuMO 40 ??? Kurmark FuMO 41 Segler (shipborne 9cm Renner) FuMO 42 Freya LZ (Flugmeldung) FuMO 51 Mammut Gustav (Flugmeldung) FuMO 52 Mammut Caesar (Flugmeldung) FuMO 53 Mammut Cacile (Flugmeldung) [U]Airborne adapted [/U] FuMO 61 Hohentwiel U (U-Boats) FuMO 62 Hohentwiel S (large ships) FuMO 63 Hohentwiel K (small ships) FuMO 64 Hohentwiel L (land based) FuMO 65 Hohentwiel UI (U-Boats) FuMO 71 Lichtenstein B/C FuMO 72 Lichtenstein (with PPI) FuMO 81 Berlin S panoramic FuMO 82 Berlin K (land based) FuMO 83 Berlin UI (U-Boats) FuMO 84 Berlin UII (U-Boats) [CENTER]-----“----- [/CENTER] [U][B]Coastal battery direction[/B][/U] (Seeart) FuMO 101 ??? (Adapted from Seetakt? 368MHz, 125kW, 16-26km. GEMA) FuMO 111 Barbara (9cm scanning picture radar). [CENTER]-----“----- [/CENTER] [U][B]Flak direction[/B][/U] (Flakziel) FuMO 201 Flakleit (land based) FuMO 202 Flakleit (shipborne, Prinz Eugen) FuMO 211 Würzburg A FuMO 212 Wurzburg C FuMO 213 Würzburg D (also Seetakt on Tirpitz) FuMO 214 Würzburg Riese (also Seetakt and Seeart) FuMO 215 SeeRiese Giant Wurzburg (also Seeart) FuMO 216 Ansbach FuMO 221 Mannheim FuMO 231 Euklid [CENTER]-----“----- [/CENTER] [U][B]Aircraft warning[/B][/U] (Flugmeldung) [U]Land based[/U] FuMO 301 Freya 39 G FuMO 302 Freya 40 G FuMO 303 Freiburg FuMO 311-318 Freiburg I FuMO 321-328 Freiburg II FuMO 331 Wassermann M FuMO 341 Freya Kothen K1 FuMO 342 Freya Kothen K2 FuMO 343 Freya Kothen K3 FuMO 371 Jagdschloss [U]U-Boats[/U] FuMO 391 Lessing FuMO ??? Ballspiel (gun directing) [CENTER]-----“----- [/CENTER]




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