German Radar

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Steve Crandell
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Re: German Radar

Post by Steve Crandell »

There is a table of radar gunnery ranges for the USN Mark 3 radar in one of Bill Jurens' articles, and it shows 10,000 yards for detection of 6" splashes from an antenna 125 feet above the water plus a pre amplifier.
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Dave Saxton
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Re: German Radar

Post by Dave Saxton »

Steve Crandell wrote:There is a table of radar gunnery ranges for the USN Mark 3 radar in one of Bill Jurens' articles, and it shows 10,000 yards for detection of 6" splashes from an antenna 125 feet above the water plus a pre amplifier.
The British 284M might be similar assuming it has a similar signal to noise ratio.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
nebfer
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Re: German Radar

Post by nebfer »

Dave Saxton wrote:.
Been reading up on German Radars, and Im getting that your of the opinion that Germanys radars in WW2 where Generally not as bad as often stated?

It's often stated that German WW2 radars where out right inferior than their allied counter parts, and a large part of that is due to their failure to develop the cavity magnetron until rather late in the war.

However your saying that this is not necessarily the case, Not that they where better than their allied counter parts but at the lest where not that far behind?

So how exactly where German Radars inferior to their allied "counter parts" in the later part of the war?

Is it say along the lines of compactness? the allies could make more compact systems? due to the use of the cavity magnetron? What advantages dose the "CM" have in radar usage in this time frame?
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Dave Saxton
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Re: German Radar

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nebfer wrote: Been reading up on German Radars, and Im getting that your of the opinion that Germanys radars in WW2 where Generally not as bad as often stated?

It's often stated that German WW2 radars where out right inferior than their allied counter parts, and a large part of that is due to their failure to develop the cavity magnetron until rather late in the war.

However your saying that this is not necessarily the case, Not that they where better than their allied counter parts but at the lest where not that far behind?

So how exactly where German Radars inferior to their allied "counter parts" in the later part of the war?

Is it say along the lines of compactness? the allies could make more compact systems? due to the use of the cavity magnetron? What advantages dose the "CM" have in radar usage in this time frame?
When I first started to research this topic I expected to find the conventional wisdom confirmed regarding the inferiority of German radar vis Allied radar. But that was not what the data indicated. In terms of performance, German radar equipment was more or less the equal to Allied radar at any given time, and clearly superior early war.

Of greater significance is how the radar was used. The German Navy dropped the ball in terms of officer training of how to better use this new technology.

There is nothing special about the cavity magnetron in and of itself. Indeed the Japanese developed the cavity magnetron independently by the early 1940s but this did not translate into superior radar equipment. In fact the performance of Japanese Type 22 radar equipment was clearly inferior to that of both Allied and German radar equipment, particularly in terms of resolution, despite their cavity magnetron, and the use of centimetric wavelength.

The main advantage of the (strapped) cavity magnetron was the ability of it to produce centimetric or microwave radiation with power outputs of tens of kilowatts. The Japanese cavity magnetrons were not strapped and early European magnetrons were also not strapped. They produced outputs of less than about 5 kilowatts. Centimetric wave lengths create much higher antenna gain without needing to use large antennas. Antenna gain is essentially how focused and concentrated the beam is. Higher antenna gain provides two main advantages. First higher gain can (but not always) result in an automatic increase in range attainment. Secondly, it can produce a narrow beam while using a relatively small antenna. The result of a narrow beam is superior bearing resolution (not resolution for distance as that is a function of time parameters not frequency).

Longer wavelengths can also utilize a narrow beam through the use of larger antennas. However, to obtain a narrow beam with metric and decimetric wavelengths can require such a huge antenna that it can become impractical for use aboard ships. This was why Freya, at 240 cm wavelength, was not used aboard ships. Seetakt still required a rather large phased array mattress antenna, at 60-80 cm wavelength, which was made even larger by 1944. The use of extra large antennas, post 1943, operating in common mode, allowed Seetakt to keep pace with late war performance demands, nonetheless.

Seetakt was originally designed with a cavity magnetron operating on 52 cm. The magnetron was designed by Dr. Hans Holmann (secret patent issued for in 1938), and mounted directly to the antenna. However, it was dropped in favor of a twin triode transmitter in early 1936. The reason it was dropped was because of the inherent instabilities of magnetrons, such as pushing and/or pulling the frequency, and the scattered and somewhat random timing of pulses (strapping helps ameliorate these problems but does not eliminate them). Seetakt used a central impulse geraete which was regulated by a master modulation. The pulses were thus precisely regulated and coordinated according to timing, and also phase. This was necessary for the proper function of the fine ranging system, which provided a excellent resolution for range using a 2 microsecond pulse width.

It is true that cavity magnetrons can result in more compact systems, using small enough antennas to be mounted at the head of a mast. The Germans applied the strapped cavity magnetron to their Berlin PPI surface search radar systems introduced by mid 1944. Berlin utilized a small radome mounted on the head of mast. Such design was not practical using Seetakt.

The primary role of Seetakt by 1944, now using extra large phased array antennas, was changed to that of firecontrol. Seetakt had the necessary accuracy (since 1940), and by 1944, with common mode antennas, and in some cases high output power, more than ample range attainment for that role.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
Steve Crandell
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Re: German Radar

Post by Steve Crandell »

A good example of poor understanding of radar in the USN was the first naval battle of Guadalcanal. Halsey had just been chosen to command the SE Pacific forces and he put Calahan in charge of the US force over Norman Scott. The latter had an excellent command of radar and night fighting from his previous experience in night battles and had been training his force. Calahan chose San Francisco as his flagship because of her good flag spaces, but she didn't have the latest radar. He should have chosen Portland or Helena. In any case, he didn't understand night fighting and made a real mess of it. He was made a hero because he was killed on the bridge of his flagship.
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Re: German Radar

Post by Thorsten Wahl »

First documented use of Funkmess for firecontrol purposes
Admiral Graf Spee Summer 1939
Dete Feuerleit 1939.jpg
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Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!
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Re: German Radar

Post by dunmunro »

Thorsten Wahl wrote:First documented use of Funkmess for firecontrol purposes
Admiral Graf Spee Summer 1939
Dete Feuerleit 1939.jpg
Thanks for that. Can you do a rough translation?
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Re: German Radar

Post by Thorsten Wahl »

secret
subject: Immediate use of "Dete" (Radar)devices
process: BN VIII 5825/39 geheim from October 10th 1939

process writing was accompanied by a report of the Panzerschiff Admral Graf Spee on a combat-practice at night.

Report Shows, that Graf Spee achieved 100 per Cent hit rate during two attack attempts at night against a target using Dete, whilst "Scheer" had Zero hits without using Dete.

The results shows need and justification of the installation of Dete devices even at the cost of replacing optical range measuring devices, if space is insufficent for additional installation.

The AGS Report was not included.
According to secret regulations; any detailed document on the "use of Funkmess" was classified as "Geheime Kommandosache" and may not used and shipped and handled together with documents of lower secrecy level(geheim or Verschlußsache) . Requirements for handling and storage of Geheime Kommandosachen were extremly restrictive. General writings without functional details on Funkmess had to use codenames (Dete, EM2, NVK Gerät) were always classified as geheim.

If a document uses the term "Funkmess" or consists device names or functional details and so on, it becames a Geheime Kommandosache.
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!
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Re: German Radar

Post by dunmunro »

Thanks.
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Re: German Radar

Post by Thorsten Wahl »

detection capapilities (as measured) of Funkmess equipment as per 01/41 used device on board Prinz Eugen
the device on bord Prinz Eugen consists also of a N.V.K. - P-Zusatz 11/40 ( Seite fein) which allows accurate measurement of the azimuth even without optical visibility

ranges
landmarks up to 75 km
ship targets(ferry near Sassnitz) 22 km
small ship (tug) 12 km
submarines half submerged 6 km
shell splashes 12 km


document
NARA Roll T-1022-2296 PG-34630, 0967.jpg

Oberkommando der Kriegsmarine B.Nr. N Wa IA 849//41 Gkds, Berlin 27.Mai 1941 Schnellkurzbrief Ortungsmöglichkeiten von U-Booten mit dem Dete-Gerät EM-II, Auszug aus dem EM-II Betriebsbuch Kreuzer Prinz Eugen
Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!
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Re: German Radar

Post by dunmunro »

Thorsten Wahl wrote: Mon May 06, 2019 2:44 pm detection capapilities (as measured) of Funkmess equipment as per 01/41 used device on board Prinz Eugen
the device on bord Prinz Eugen consists also of a N.V.K. - P-Zusatz 11/40 ( Seite fein) which allows accurate measurement of the azimuth even without optical visibility

ranges
landmarks up to 75 km
ship targets(ferry near Sassnitz) 22 km
small ship (tug) 12 km
submarines half submerged 6 km
shell splashes 12 km


document
NARA Roll T-1022-2296 PG-34630, 0967.jpg

Oberkommando der Kriegsmarine B.Nr. N Wa IA 849//41 Gkds, Berlin 27.Mai 1941 Schnellkurzbrief Ortungsmöglichkeiten von U-Booten mit dem Dete-Gerät EM-II, Auszug aus dem EM-II Betriebsbuch Kreuzer Prinz Eugen
Thanks. is there any measurements of bearing accuracy?
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Re: German Radar

Post by Thorsten Wahl »

EM2 capabilities at the begin of 1941

From an own post at axishistory Forum
the War Diary of Gneisenau consist of an addendum "experience report on the use of EM2 (radar)
during the Feb March 1941 undertaking

Ranges for tactical search were the same as ranges obtained with optics depending on height of the target(reflective surfaces).
ranges obtained for the fine ranging unit were about 7 % less then the tactical instrument with accuracy ~ 50 m (later specified) but clearly better then the differences of the optical equipment.

distant contacts -prominent Landmarks- could be seen up to 160 km -canary islands / jan mayen Norwegian coast as well as Aircraft

(there were also unusual overreaches - up to 400 -700 km around the Canaries)
distant contacts were identified and measured by changing puls repetition frequency via Frequenzumschalter

development of suppression of distant return signals using frequency wobble.

they had a zoomable spotting unit for shell impacts ->electronic zoom ranging unit(Messkette) for the area +-1000 m around the target
Aufschlagmessgerät.jpg
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Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!
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Dave Saxton
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Re: German Radar

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During Operation Berlin S&G still operated FUMG39 sets. The MK2 sets were available and installed on new construction. However, S&G did not get the updated technology until after they arrived at Brest.
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.
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Re: German Radar

Post by OSCSSW »

I'm a bit late to this topic. Most of the above posts seem to concentrate on Tirpitz and late war German naval Radars. I have been looking more at Bismark and early second world war naval radars.


The following excerpts are from NAVWEAPS article By Erwin F. Sieche

Although German radar development was very promising in its early stages it was quickly overtaken by allied technology. One major reason for this was that the German Navy, which was the most conservative of the three services, did not realize the full potential of active radar, leaving the Allies in a favorable position to force the pace of the microwave war. The German Navy had decided that radar transmissions would provide a source from which an enemy could obtain a 'fix' on a ship's position, in the same way that direction-finders could be used to obtain a 'fix' on the source of a radio transmission. Extensive use of radar was therefore discouraged, a decision reinforced by the German belief in the superiority of their optical equipment. It is significant that young officers were taught absolutely nothing about radar and had to learn from scratch about the complex microwave war while on active service, in conditions where any fault could be fatal. It was not until March 1945 that German Naval Command issued Tactical order No 10 entitled Instruction for use of radar aboard surface units.

Thus the story of German naval radar in surface units is one of 'too lates'. The other services, especially the Luftwaffe, the Flak (AA) troops and even coast defense artillery, employed radar skillfully and extensively, while the Navy was tardy in proving information and training in new technology.

Knowledge of high-frequency radio emissions was therefore limited and the quality of the radar aboard German ships depended substantially on the personnel interest of the responsible radio officer. Only a few of these were electronic experts, by virtue of being enthusiastic, and even fewer had good contacts in the electronic industry, thus reducing their chances of improving sets in service. It is not surprising therefore that, under the rough conditions aboard a ship, the sensitive electronic equipment soon deteriorated and became faulty. Many surface units did not have their radar equipment recalibrated during the long periods of their careers! Thus sets became so unreliable that the commander refused to use them - an easy decision, when asked to hold strict radar silence whenever possible.

To counter the superior Allied radar technology, German surface vessels were fitted with more and more passive sets, the field becoming so extended that description of the German passive radar-sets, the Funkmess-Beobachtungsgeräte or FuMBs has been reserved for a separate article.

Both Admiral Graf Spee and Deutschland have been claimed to be the first German naval vessels to be fitted with radar. Trenckle says that Admiral Graf Spee had an experimental FuMO 22, and Prager that Deutschland had a Seetakt set in the autumn 1937 (which proved very useful for night navigation in Spanish waters). Photographic analysis shows that the frame of this first experimental set was slightly smaller (0.8m x 1.8m) than the final FuMO 22 frame, but it is not known if there were fewer dipoles or alternatively if the dipoles were placed closer together.

R V Jones, in his memories (Most Secret War, Hamish Hamilton, 1978) describes how the British Admirality sent L H Bainbridge-Bell to the River Plate to examine the radar installation aboard the wreck of the Graf Spee. According to Price (Instruments of Darkness, Kimber, 1967) the resultant report took one and a half years to pass through the official channels, a statement I find hard to believe considering that Bainbridge-Bell had been sent half around the world to abtain the information. It adds yet another intriguing possibility of further information, as this report, possibly including photos of Graf Spee's installation, may yet come to light.

The Deutschland (renamed Lützow in 1940) had a 2m x 6m mattress antenna for a FuMO 22 throughout her wartime career. From January 1942 until March 1944 she also had a Timor frame at the rear of her radar tower, as in the Scharnhorst. To follow German practice there should also have been fixed Sumatra antennas but they cannot be traced in photographs.

It is noteworthy that the foretop radar of the armoured ships (later reclassified as heavy cruisers) were provided with the best positioning of any German heavy units. It was situated at the highest point in the ship, and the foremast was removed, and replaced by a short pole mast, to provide completely unobstructed all-around coverage.

Scharnhorst Class

In November 1939 both these vessels were equipped with an 81.5cm (368MHz) FuMO 22 situated in an additional tower above the forward rangefinder tower. The 2m x 6m mattress antenna on the front of the tower rotated with the 10.5m rangefinders so the result from both instruments could be compared. During their stay at Brest in the summer 1941 they were fitted with a FuMO 27 on the after rangefinder tower and for their 'Channel dash' in 1942 both were probably equipped with a passive Palau antenna on a small frame at the back of their rangefinder tower, which thus operated in the reciprocal direction to the rangefinder and the active FuMO.

During a refit in Germany Scharnhorst received a new FuMO 26 or 27 set, with a 2m x 4m mattress antenna, under which was a smaller frame for the two rows of vertical and horizontal Timor dipoles serving the passive FuMB 4 Samos set.

To follow standard German practice there should also have been passive Sumatra antennas somewhere on the screen around the foretop rangefinder platform; however, they cannot be traced in any photography. It can also be assumed that they carried a small omni-directional round dipole FuMB 3 Bali, but the antenna for this set is to small to be clearly identified. It would have been fitted on the top of the foremast or on a yardarm.

he most modern unit of this class, the short-lived Blücher, had her foretop rangefinder tower crowned by an additional radar tower carrying the 2m x 6m mattress of FuMO 22, but no battle-observer's post.


Bismarck Class

As the added weight of the radar tower resulted in a critical surplus load on the sensitive bearing engines of the rangefinder tower, both these battleships were fitted with enlarged towers, for all three gunnery rangefinders, housing both a FuMO 23 and the optical equipment. The installation of a fourth mattress antenna on the front of Bismarck's conning tower is the subject of controversy in German literature. The dimension of the structure appear to indicate that it had two rows of dipoles for active or passive detection, but the clarifying details are obscured in all photographs by a canvas cover.

The Tirpitz was re-equipped while she was based in Norway as part of the German standby force. Probably in January 1942 the foretop rangefinder tower was topped with an additional radar tower, carrying a FuMO 27 mattress antenna and a smaller frame, for the Timor antennas, above it. The sides and the rear of the radar tower were fitted with Sumatra antennas. In about the spring or summer of 1944 Tirpitz received an enlarged 3m x 6m mattress antenna, probably for FuMO 26. Careful examination of Tirpitz photographs reveals a small frame of a pole on top of the foretop tower, later moved to a bracket on the foremast to avoid interference with the FuMO 26. It is possible that this was either an experimental installation of FuMO 30 or the later standard frame for the Palau dipoles serving a FuMB 6. The addition of a trainable antenna frame to supplement the fixed antennas seems logical, but this would be the only appearance of a FuMO 30 on a German surface unit, it having originally been developed to submarines.

Again in the spring or summer of 1944, the third AA director, fitted just abaft the mainmast (German nickname 'Wackeltopf') was raised by 2m and equipped with an AA gunnery radar, probably Würzburg-C or Würzburg-D. As previously mentioned the Würzburg had originally been developed for the Luftwaffe, but it was later navalised for the German Navy's AA shore batteries under the following designation: FMG 39T/C (later FuSE 62C) Würzburg-C became the Navy FuMO 212, and FMG 39T/D (later FuSE 62D) Würzburg-D became the Navy FuMO 213. This reveals a fact that has not previously been published.

Tirpitz had the most sophisticated radar equipment of all the larger German surface units. However, without interviewing eye-witnesses we cannot know that these sets were not experimental, nor how effective they were under battle conditions. In this connection it would be most interesting to read British intelligence reports on the ship and to see Torstein Raaby's photographs of her. Torstein Raaby, who became famous after the war as member of Thor Heyerdahl's Kon Tiki expedition, was with the Norwegian resistance during the war and for ten months the spent much of his time on the top of the church tower of the Village of Alta watching the movements of the German capital ships lying in Kaa Fjord.

Admiral Hipper had similar equipment, but probably during her refit of late 1941 to early 1942, she received battle-observer's post atop the forward radar tower and a Timor frame on its rear. The after rangefinder was also topped by a radar tower for a FuMO27. There are astonishingly few photographs showing this ship after her recommissioning in March 1944, and little information is therefore available on her final radar fit. After February 1945 she docked at Deutsche Werke Kiel, where she was scuttled by her crew in May 1945.

Two postwar photographs taken during an examination by high ranking British officers immediately after the German capitulation, show that Admiral Hipper was to have been equipped with a FuMO 25 similar to Prinz Eugen (as picture 7.2), the scaffolding and the central revolving pole being clearly visible.

Prinz Eugen, which did not commission before August 1940, was, in contrast to Bismarck, fitted with enlarged rangefinder towers, one aft and one on the foretop, for FuMO 27 sets with 2m x 4m mattresses. Probably during her refit after the dash, her foretop rangefinder was crowned by an additional radar office, the equipment fitted being in some way very similar to that of Tirpitz: above the 2m x 4m mattress of FuMO 26, below the slightly smaller Timor frame, both bearing in the same direction, while passive Sumatra antennas, bearing in all four directions, were situated on the screen of the foretop platform. She was, however unique in having a special hightfinder set with an aerial consisting of two rectangular frames which could be switched in elevation. The left one carried the active dipoles, the right the passive 'butterfly' dipoles with vertical polarisation.This may have been an experimental set for air search and/or for AA fire control. It was removed at the same time as Tirpitz received her superior Würzburg.

In her fnal configuration Prinz Eugen carried a huge 3m x 6m mattress for FuMO 26 on the face of her radar tower and an antenna on the foremast for the most sophisticated German radar set of the war - a FuMO 81 Berlin-S panoramic reconnaissance radar working on a wavelength of 6cm. The passive equipment consisted of the standard Sumatra, and the cone-shaped FuME 2 Wespe-G (2) atop the forward radar tower. It may be assumed that there were also Bali dipoles, but these are too small to be detected in photographs.

From August 1944 the Prinz Eugen carried a FuMO 25 (as fitted in destroyers) on her mainmast yardarm. Due to its position, this set could only be used on bearings from 35º to 325º, although it had 360º training.

None of the German light cruisers which took part in the assault on Norway had radar.
"You see those battleships sitting there, and you think they float on the water, don't you?... You are wrong, they are carried to sea on the backs of those Chief Petty Officers!" Admiral William Halsey USN :wink:
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Re: German Radar

Post by wmh829386 »

:stubborn:

What is the purpose of copy and pasting the article that contains numerous flaws, many of those were pointed out by earlier post...
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