German Naval Radar

Updated 17 October 1999
3. Radar Designation
With the outbreak of the Second World War, radar development became very complex and, from the historian's point of view, it is difficult to provide a complete record of events.  On the one hand the needs of the three services resulted in separate development to meet their individual requirements, and in each case a different system of code designation was adopted.  For reasons of secrecy, and due to a degree of jealousy, inter-service communication was poor, and subsequent development depended significantly on personal contacts between the services and the contractors' scientist.  On the other hand the contractors themselves were working for all three services and, naturally used ideas developed for the equipment of one service in that of the others.  It was only in the second half of the war that attempts were made to introduce a uniform system of designation for radar sets. Up to this point, there existed no fewer than six different classifications.  For example, in the third system introduced, in the surveillance radar FuSE 80 Freya, 'Fu' means Funkmess (radar), 'S' means Siemens (the manufacturer), 'E' refers to the set's function (in this case Erkennung or reconnaissance), '80' is the running number and Freya the set's code word.  Sometimes a code was added for the type of installation, eg FuSE 62A Würzburg, in which 'A' means stationary ground installation with mechanically rotated aerial; to confuse matters the AA gunners of the time referred to this set as FuMG (Flak) 40T/A.

The early sets were simply called DeTe I (or sometimes set A1), DeTe II and so on.  When the family of German radar sets began to grow this was found to be insufficient, and arabic numbers were introduced, 100 to 199 being reserved for naval tactical sets working on a wavelength of 80cm.  In 1938 a more specific designation system was introduced, giving fuller details of the set; for example the first set installed aboard the armored ship Admiral Graf Spee was FMG 39G (gO).  The 'FMG' means Funkmessgerät (radar device), '39' is the year of introduction (1939), 'G' is the manufacturer (GEMA), 'g' is the frequency code (335-430MHz) and 'O' is the type of aerial installation (radar tower on top of the rangefinder tower).  See tables below for full list.

T Telefunken
L Lorenz
S Siemens
L trainable antenna on top of bridge
M trainable antenna on a yardarm
O battleships; radar tower, or hut, on top of a rangefinder
P battleships; radar root integral with enlarged rangefinder tower
S fixed antenna on torpedo boats
U submarine version
c 182 to 215MHz
f 120 to 150 MHz
g 335 to 430 MHz
kl 95 MHz
  and so on
Table 1: Manufacturers  Table 2: Type of antenna installation  Table 3: Frequency bands
In about 1943 these designations were replaced by a standardized system, giving code letters for the type of set and a running number, details are given in Table 4 (which also includes the old DeTe code for clarification).  Existing sets were recorded under this system, the FMG 39G (gO) for example becoming FuMO 23, the FMG 39G (gP) becoming FuMO 23, the FMG 39G (gL) becoming FuMO 21, and so on.  However, the codewords for the sets were retained through all the systems so a Freya, for example, was always called a Freya by its operators.  It should be pointed out that the above refers only to the genealogy of the naval coding systems; the Wehrmacht and the Luftwaffe employed different designations, although some of the basic naval sets were the same as the landbased Würzburg (for reasons of simplicity, the following description of the radar installation aboard German ships employ only the last designation system, so only FuMO-, and FuMB-, etc, sets are referred to).
Type Frequency
[º +/-]
FuMO 21 368 14-18 70 m 3 Destroyers
FuMO 22 368 ? - - Capital ships
FuMO 23 368 ? - - Capital ships
FuMO 24/25 368 15 - 20 70 0.3 Capital ships, destroyers
FuMO 26 368 20 - 25 70 0.25 Capital ships
FuMO 30 368 6 - 8  100 5 Submarines
FuMO 61 Hohentwiel-U 556 8 - 10 150 3 Submarines
FuMO 63, Hohentwiel-K  556 to 567 12 - 20 150 2  
FuMO 81 Berlin-S 3300 20-30 100 5 Surv set, Prinz Eugen, destroyers, E-boats
FuMO 213 Wuerzburg-D 560 40 - 60 35 1.15 AA gunnery
FuMB 7 Timor - passive - -  ?
Palau - passive - - ?
FuMB 3
- passive - - ?
FuMB 4 Sumatra - passive - - ?
Seetakt - - -   ? -

Table 4: Particulars of the principal German radar sets
The various type designations were in fact even more complex than the above indicates, for every small alternation in the type of installation, the function, frequency and other modifications, resulted in the provision of a new code.  In addition, each installation consisted of two basic parts - the set itself and the antenna - and as it was possible to interchange these, using the antenna of one set with the primary equipment of another, yet another level of designation was possible.  Thus a precise listing of all German naval radar sets is almost impossible, and no such list exists in any German literature.  Even a simplified listing of radar type designations, with their technical particulars, would require a intensive research in German and foreign archives, and the interviewing of surviving witnesses by a researcher export in both radio technology and naval history.  Thus it is not possible to guarantee complete accuracy in describing the radar installations in German warships but hoped that this article will provide stimulation for further detailed study in this complex and poorly recorded area.

There is one hope of full clarification:  The Allied mission to Germany at the end of the Second World War produced many detailed studies of German developments.  Among them was, presumably, a report on radar (possibly including drawings and photographs of the sets in surviving German naval units), copies of which are probably buried somewhere in the US and British archives.  Hopefully they will eventually be released, allowing somebody to discover and publish them.

For the above reasons the following description of German naval radar concentrates mainly on the visible differences in antennas.  As contemporary literature on Second World War German warships includes a great number of excellent pictorials (see Bibliography), this article does not use photographs to illustrate all the variations in radar equipment in Kriegsmarine vessels but concentrates on giving general coverage by means of drawings so that the reader may try to identify the different system in his own personal library by using these as a guide.  However, some caution is required because in the majority of such photographs I have noted that the antennas have been carefully turned end-on so one can see that there is a mattress antenna, but cannot see sufficient detail to identify it.  Moreover, in the second half of the war the antennas in the centimetric field became so small that the are often mistaken for blocks or anemometers.  The reverse is also true; for example, one of the distinctive items on German naval units in the later period of the war was a trumpet-shaped object which might be mistaken for radar but is in fact an acoustic fog-horn.  There only exist about five really good postwar photographs of German warships showing their full complement of active and passive radar antennas, from the 2m x 6m mattress of the FuMO 24/25 to the small cone of the FuME 2 Wespe g.

Classification Translation
Dezimeter-Telegraphie (DeTe) Decimeter-Radio - the first German codeword for radar, sometimes misinterpreted as Deutsches Technisches Gerät
Funkmess (FuM) Radar set
Funkmess-Ortung (FuMO) Radar - direction finder, active ranging.
Funkmess-Beobachtung (FuMB) Radar - detector, passive detection (of enemy radar transmission).
Funkmess-Erkennung (FuME) Radar - detector, active Identification Friend/Foe (IFF).
Funkmess-Störsender (FuMS) Radar - interference sender, active jamming.
Funkmess-Täuschung (FuMT) Radar - deceptor, active deception (by means of transmitting interference signals).
Funkmess-Zusatz (FuMZ) Radar - with very specialized improvements for various purposes (eg, high-precision bearing).

Table 5: German Radar Coding System, c1943

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