Tirpitz' Radar

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Christian VII.
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Re: Tirpitz' Radar

Postby Christian VII. » Tue Jan 20, 2015 9:32 pm

Very interesting Dave, it all makes a lot more sense now. I honestly couldn't understand how the Germans could've been behind in this field considering all the work they had done before the war, heck I've even read that a German patent for the cavity magnetron was filed in the 30's. In addition to this I found it odd that the Germans somehow wouldn't have quickly copied the Allied centimetric radar sets captured already in 1943, and indeed as you mention they infact did - none of which is mentioned in Norman's book for example.

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Re: Tirpitz' Radar

Postby Dave Saxton » Tue Jan 20, 2015 9:47 pm

but I didn't know that they made radar sets late in the war that actually outperformed the late war allied sets so comprehensively. ☺

I wouldn't say that it out performed Allied radar comprehesively. The high powered transmitters gave Seetakt some astonishing range capabilities, but there is some question of if and how many of these sets were actually deployed during the increasingly chaotic final year of the war. Fritz Trenkle was of the opinion that the FuMO26 sets on Tirpitz were actually FuMO34 sets with 125kw of power. I'm not so sure. For one thing the modulators for the 125kw transmitters were known to be unreliable, so its unlikely that they would deploy an unreliable piece of equipment on a warship such as the Tirpitz. Did they solve the reliability problem? Did they deploy the modules as an optional add on? I don't know?

The creation of the 400kw transmitters was a result of efforts to build a more reliable high power modulator. Spark gap modulation was used which resulted in a reliable 400 kilowatt output, but it also created other problems that would have taken time to work out. The Germans were quickly running out of time during 1944.

The regular FuMO26 was still a good piece of equipment by the standards of 1944, giving similar performance in the FC role to the USN's MK8.
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: Tirpitz' Radar

Postby Dave Saxton » Tue Jan 20, 2015 9:57 pm

Christian VII. wrote:. In addition to this I found it odd that the Germans somehow wouldn't have quickly copied the Allied centimetric radar sets captured already in 1943, and indeed as you mention they infact did.

Giessler points out that the existing Seetakt technology had the necessary precision for improved firecontrol, it was a just a question of increasing the range first by larger antennas and then by high power. This was by far the best option for the Germans at the time.

The centimetric technology was of course a no brainer for a PPI surface search set-which they badly needed. The Allies had an advantage in terms of surface search sets from late 1941 through 1943. The misconception is that the Allied advantage was firecontrol radar, when it was actually surface search radar and the situational awareness that comes from it.
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: Tirpitz' Radar

Postby dunmunro » Tue Jan 20, 2015 11:34 pm

Dave Saxton wrote:


1940-41...........German...............British..........USN
Range accuracy:..40 meters...........240 yards(1).........N/A
Bearing Accuracy..0.10*................0.75*..............N/A

1942-43..........German................British..........USN
Range Accuracy:..40 meters............120 yards(2)......0.1% of range + 40 yards
Bearing axxuracy..0.10*.................5-6 arc M (0.08*)...........3-4 mils (0.12-0.20*)

1944-45.........German ................British....................USN
Range accuracy:.25 meters.............120 or 40 yards..........0.1% of range + 15 yards.
Bearing Accuracy: 0.10*.................0.8*-0.10*................2-3 mils

.


(1) dual scale range output. 0-24k yd scale = 120 yd accuracy. 0-48k scale = 240 yd accuracy.
(2) PRPs were fitted to type 284/5 radar in this time frame resulting in better range accuracy than shown.

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Re: Tirpitz' Radar

Postby Thorsten Wahl » Wed Jan 21, 2015 9:57 am

Christian VII. wrote:
Thorsten Wahl wrote:Ther is a guy quoting Dave and you are wandering around in the gaps left. but no problem come to the "experts" :whistle:


Are you talking about this thread?: http://forum.worldofwarships.eu/index.p ... -and-wwii/

If so I was actually reading it all this time, and it is indeed one of the reasons for my questions :D


yes my name in other forums like this is "Thoddy" or "Thoddyx"
------------------------------------------------------------------------------
2-3 mils


360 degrees are 6000 mils?
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Re: Tirpitz' Radar

Postby Byron Angel » Wed Jan 21, 2015 11:48 am

From Wiktionary -
"A unit of angular measurement equal to 1/6400 of a complete circle. At 1000 metres one mil subtends about one metre (~0,98 m). Also 1/6000 and 1/6300 are used in other countries."

The US WW2 service standard mil angular measure was based upon the (approx) 1 unit of arc at a radius of 1000 units standard, i.e. 6400 mils corresponds to 360 degrees. Hence, one angular degree = 17.778 mils.

B

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Re: Tirpitz' Radar

Postby Christian VII. » Wed Jan 21, 2015 12:03 pm

dunmunro wrote:
Dave Saxton wrote:


1940-41...........German...............British..........USN
Range accuracy:..40 meters...........240 yards(1).........N/A
Bearing Accuracy..0.10*................0.75*..............N/A

1942-43..........German................British..........USN
Range Accuracy:..40 meters............120 yards(2)......0.1% of range + 40 yards
Bearing axxuracy..0.10*.................5-6 arc M (0.08*)...........3-4 mils (0.12-0.20*)

1944-45.........German ................British....................USN
Range accuracy:.25 meters.............120 or 40 yards..........0.1% of range + 15 yards.
Bearing Accuracy: 0.10*.................0.8*-0.10*................2-3 mils

.


(1) dual scale range output. 0-24k yd scale = 120 yd accuracy. 0-48k scale = 240 yd accuracy.
(2) PRPs were fitted to type 284/5 radar in this time frame resulting in better range accuracy than shown.


Which time frame? 43-44 or 44-45?

Was the range accuracy improved so as to be comparable to the German & US radar?

Also it seems as though the British had a radar set providing extremely accurate bearing readings in 43, why would they revert back to a less accurate one in 44-45? Would I be correct im assuming it was done in exchange for more range as 0.8 deg precision was seen as more than adequate?

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Re: Tirpitz' Radar

Postby Dave Saxton » Wed Jan 21, 2015 3:53 pm

Christian VII. wrote:Which time frame? 43-44 or 44-45?

Was the range accuracy improved so as to be comparable to the German & US radar?

Also it seems as though the British had a radar set providing extremely accurate bearing readings in 43, why would they revert back to a less accurate one in 44-45? Would I be correct im assuming it was done in exchange for more range as 0.8 deg precision was seen as more than adequate?


Oh, that is a typo. It shoud be 0.08*

According to Byran Calick (British radar scientist involved at the time) there were two PRPs used during those periods. Also Calick informs that there was a random delay between when the thyratron pulser was keyed and when it actually fired which gave it a potential ranging error of about 100 meters regardless. The PRP measured electronically the time-distance between the firing of the pulse and the pip to an accuracy of 25 yards, but the exact time of the firing of the pulse on these sets wasn't exact. With the spark gap modulator on Type 274 the exact time of the sending of the pulses was slightly scattered, meaning the 25 yard spec could not be obtained in practice.
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: Tirpitz' Radar

Postby dunmunro » Wed Jan 21, 2015 7:04 pm

Christian VII. wrote:
dunmunro wrote:
Dave Saxton wrote:


1940-41...........German...............British..........USN
Range accuracy:..40 meters...........240 yards(1).........N/A
Bearing Accuracy..0.10*................0.75*..............N/A

1942-43..........German................British..........USN
Range Accuracy:..40 meters............120 yards(2)......0.1% of range + 40 yards
Bearing axxuracy..0.10*.................5-6 arc M (0.08*)...........3-4 mils (0.12-0.20*)

1944-45.........German ................British....................USN
Range accuracy:.25 meters.............120 or 40 yards..........0.1% of range + 15 yards.
Bearing Accuracy: 0.10*.................0.8*-0.10*................2-3 mils

.


(1) dual scale range output. 0-24k yd scale = 120 yd accuracy. 0-48k scale = 240 yd accuracy.
(2) PRPs were fitted to type 284/5 radar in this time frame resulting in better range accuracy than shown.


Which time frame? 43-44 or 44-45?

Was the range accuracy improved so as to be comparable to the German & US radar?

Also it seems as though the British had a radar set providing extremely accurate bearing readings in 43, why would they revert back to a less accurate one in 44-45? Would I be correct im assuming it was done in exchange for more range as 0.8 deg precision was seen as more than adequate?



DoY had a type 284M3 radar and used it in action in Dec 1943 and it included a highly accurate ranging panel, so we know that in 42-43 the type 284 could achieve better than 120yd accuracy:
DoY used a Type 284M(3) set at North Cape, in conjuction with both L12 (for splash spotting) and L18 (for ranging) panels. The L18 panel is described as a precision panel by it's designer C.A. Laws, so 284M did receive precision ranging panels despite the lack of the "P" suffix:

(6) "EMBODIMENT OF THE RANGING SYSTEM IN NAVAL
EQUIPMENT
The ranging system described has been incorporated in the
naval display panels LI3, LI7 and LI8, and has proved extremely reliable and consistent.
The overall accuracy depends
somewhat on the particular application but is in general a function
of three main factors. These are (1) error in crystal frequency,
(2) cyclic error of phase-shifter, and (3) setting error. The first
of these may be rendered negligible by a suitable choice of
crystal, the second has been shown to be less than 5 yd, and the
third, which depends (as in any system) on the nature of the
target, degree of fading, etc.; is usually less than 10 yd..."
A precision-ranging equipment using a crystal oscillator as a timing standard
Laws, C.A.
Electrical Engineers - Part IIIA: Radiolocation, Journal of the Institution of
Volume: 93 , Issue: 2
Digital Object Identifier: 10.1049/ji-3a-1.1946.0127
Publication Year: 1946 , Page(s): 423 - 440
IET JOURNALS & MAGAZINES


Of course DoY's type 273 also had a precision ranging panel and gave ~25 yd ranging accuracy but could not give high accuracy in bearing, IIRC.

DoY could spot 14in fall of shot up with the type 284m3 up to 20k yds and could use the Type 273 beyond that range, but as her type 273 had a PPI display Fraser preferred to use it to coordinate his forces.

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Re: Tirpitz' Radar

Postby Thorsten Wahl » Fri Jan 23, 2015 10:36 am

@Duncan
thank you very much for the additional inputs
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Re: Tirpitz' Radar

Postby Siegfried » Thu Dec 29, 2016 3:40 pm

Dave Saxton wrote:
but I didn't know that they made radar sets late in the war that actually outperformed the late war allied sets so comprehensively. ☺


Snip

Fritz Trenkle was of the opinion that the FuMO26 sets on Tirpitz were actually FuMO34 sets with 125kw of power. I'm not so sure. For one thing the modulators for the 125kw transmitters were known to be unreliable, so its unlikely that they would deploy an unreliable piece of equipment on a warship such as the Tirpitz. Did they solve the reliability problem? Did they deploy the modules as an optional add on? I don't know?
Snip
The regular FuMO26 was still a good piece of equipment by the standards of 1944, giving similar performance in the FC role to the USN's MK8.


von Krogge in his history of GEMA (the company that designed SeeTakt) says that design of the 120kW modulators was complete in 1942 but that they were used on land based SeeTakt. If they 120kW modulators were ready in 1942 that gives them at least 2 years to perfect them for shipboard use.


One thing that makes me think they were installed was their detection range during Operation Catecism. The Lancaster's formed up over Lake Tornea Trask in Sweden (near Abisko and Kiruna) which is over 160 kilometres South East of Tromso where Tirpitz was moored and eventually sunk.

Some accounts say the Tirpitz picked the bombers up at 150km which would have been just as they cleared the mountains around the lake. Some accounts attribute the detection to radar but aren't clear as to whether it was the Tirpitz's radar or ground radar, some just mention observation and say it was an exceptionally clear day (Zetterling).

If the Tirpitz was observing the Bombers by radar at 150 kilometres then she probably had FuMO 34 as FuMo 26 didn't perform this well. Either way the Tirpitz was observing the Lancasters at 150km. Could a FuMO 26 have picked up a squadron of Lancasters at 150km?

http://www.bismarck-class.dk/tirpitz/hi ... chism.html
They reached the rendezvous about 0935 low over Tornea Trask, a (Swedish) lake a 160 kilometer (100 miles) south-east of Tromsø, took up formation and then they flew towards north-west, climbing to 4,267 meter (14,000 feet) to clear the mountains and gain height for the bombs. Radar picked them up as they gained height and the race was on, a race made even more tense than formerly by the knowledge that a German fighter squadron had recently been posted to Bardufoss.



This account I found on the internet:
07:38 The first observation of Lancasters are made at Mosjøen in Nordland

08:00 Reports of the sightings are sent to Division Flugmeldungszentrale (DFZ) at Bardufoss, and Commander of aa on Tirpitz Fassbender.

08:15 More sightings of bombers south in Norway gives rise to suspicion that a repetition of the raid of 29th of October is underway. (Reports of sightings starts to multiply, and there seem to have been several 'ghost planes' over Northern Norway that day. On telephone Fassbender requests permanent readiness at Bardufoss, but (maybe because they assess the threat differently) hauptflugwache Tromsø doesn't communicate that to DFZ.

08:51 Full air alarm is struck on Tirpitz. (Though there is variance about the time in different German reports).

09:05 Enemy aircraft can be observed from Tirpitz's observation posts approximately 150 km out.

09:14 Air alarm on Bardufoss. Enemy formation is to the east of it.

09:18 Major Ehrler orders highest readiness for take off at Bardufoss.

09:23 Major ehrler orders scramble and takes off in his 109. 9./JG 5 (Fw 190A) is hindered in following immidiately, as a Ju (88 or 52) attempts to land at exactly that moment. Ehrler, seing that he is not followed, and finding his radio inoperable, starts to search for the enemy planes on his own.

09:30 6 more fighters manage to take off from Bardufoss, though confusion and failures in communication abounds. Except for 2 ghostplanes dissapearing into Swedish territory, no interceptions are attempted.

09:34 Tirpitz starts shooting at the lancasters some 12 kilometers out.

09:36 All operational fighters at Bardufoss are airborn.

09:38 The bombs starts impacting around and on Tirpitz (according to the war diary of 617th the first bomb is released 09:41).

09:50 tirpitz capzises.

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Re: Tirpitz' Radar

Postby Siegfried » Thu Dec 29, 2016 3:41 pm

Dave Saxton wrote:
but I didn't know that they made radar sets late in the war that actually outperformed the late war allied sets so comprehensively. ☺


Snip

Fritz Trenkle was of the opinion that the FuMO26 sets on Tirpitz were actually FuMO34 sets with 125kw of power. I'm not so sure. For one thing the modulators for the 125kw transmitters were known to be unreliable, so its unlikely that they would deploy an unreliable piece of equipment on a warship such as the Tirpitz. Did they solve the reliability problem? Did they deploy the modules as an optional add on? I don't know?
Snip
The regular FuMO26 was still a good piece of equipment by the standards of 1944, giving similar performance in the FC role to the USN's MK8.


von Krogge in his history of GEMA (the company that designed SeeTakt) says that design of the 120kW modulators was complete in 1942 but that they were used on land based SeeTakt. If they 120kW modulators were ready in 1942 that gives them at least 2 years to perfect them for shipboard use.


One thing that makes me think they were installed was their detection range during Operation Catecism. The Lancaster's formed up over Lake Tornea Trask in Sweden (near Abisko and Kiruna) which is over 160 kilometres South East of Tromso where Tirpitz was moored and eventually sunk.

Some accounts say the Tirpitz picked the bombers up at 150km which would have been just as they cleared the mountains around the lake. Some accounts attribute the detection to radar but aren't clear as to whether it was the Tirpitz's radar or ground radar, some just mention observation and say it was an exceptionally clear day (Zetterling).

If the Tirpitz was observing the Bombers by radar at 150 kilometres then she probably had FuMO 34 as FuMo 26 didn't perform this well. Either way the Tirpitz was observing the Lancasters at 150km. Could a FuMO 26 have picked up a squadron of Lancasters at 150km?

http://www.bismarck-class.dk/tirpitz/hi ... chism.html
They reached the rendezvous about 0935 low over Tornea Trask, a (Swedish) lake a 160 kilometer (100 miles) south-east of Tromsø, took up formation and then they flew towards north-west, climbing to 4,267 meter (14,000 feet) to clear the mountains and gain height for the bombs. Radar picked them up as they gained height and the race was on, a race made even more tense than formerly by the knowledge that a German fighter squadron had recently been posted to Bardufoss.



This account I found on the internet:
07:38 The first observation of Lancasters are made at Mosjøen in Nordland

08:00 Reports of the sightings are sent to Division Flugmeldungszentrale (DFZ) at Bardufoss, and Commander of aa on Tirpitz Fassbender.

08:15 More sightings of bombers south in Norway gives rise to suspicion that a repetition of the raid of 29th of October is underway. (Reports of sightings starts to multiply, and there seem to have been several 'ghost planes' over Northern Norway that day. On telephone Fassbender requests permanent readiness at Bardufoss, but (maybe because they assess the threat differently) hauptflugwache Tromsø doesn't communicate that to DFZ.

08:51 Full air alarm is struck on Tirpitz. (Though there is variance about the time in different German reports).

09:05 Enemy aircraft can be observed from Tirpitz's observation posts approximately 150 km out.

09:14 Air alarm on Bardufoss. Enemy formation is to the east of it.

09:18 Major Ehrler orders highest readiness for take off at Bardufoss.

09:23 Major ehrler orders scramble and takes off in his 109. 9./JG 5 (Fw 190A) is hindered in following immidiately, as a Ju (88 or 52) attempts to land at exactly that moment. Ehrler, seing that he is not followed, and finding his radio inoperable, starts to search for the enemy planes on his own.

09:30 6 more fighters manage to take off from Bardufoss, though confusion and failures in communication abounds. Except for 2 ghostplanes dissapearing into Swedish territory, no interceptions are attempted.

09:34 Tirpitz starts shooting at the lancasters some 12 kilometers out.

09:36 All operational fighters at Bardufoss are airborn.

09:38 The bombs starts impacting around and on Tirpitz (according to the war diary of 617th the first bomb is released 09:41).

09:50 tirpitz capzises.

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Re: Tirpitz' Radar

Postby Dave Saxton » Fri Dec 30, 2016 3:09 am

Siegfried wrote: Could a FuMO 26 have picked up a squadron of Lancasters at 150km?


Most likely. We have a base line for Seetakt picking up aircraft from the Dec 1939 air raid against the Wilhelmshaven anchorage. Seetakt picked up the bombers at 113 km. At that time the power output for Seetakt was only 2 kilowatts and the antenna did not operate in common mode. The 4 fold increase in power in 1940 increased typical range attainment 20%. FuMO26 used an extra large antenna that operated in common mode. We know from primary documents that the FuMO26 antennas increased typical range an additional 30% with the same 8-9 kw power output from the transmitters.

We also have actual data of Seetakt range attainment while using the high powered transmitters from May 1944 tests of the prototype modules.The range to ships exceeded 40 km (some sources list 50 km to a battleship for FuMO34) and to aircraft the range exceeded 200 km.

However, Tirpitz probably would not have been operating FuMO26 prior to the air raid that destroyed it during Nov 1944. By that time Seetakt was almost exclusively used for fire control. Tirpitz was equipped with FuMO81 Berlin search radar sets with PPI indicators and also a Hohentwiel or a Sophie radar stepped on the foremast which would be better for air warning than Berlin. Either Hohentwiel or Sophie could easily reach 150 km to aircraft.
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: Tirpitz' Radar

Postby Dave Saxton » Fri Dec 30, 2016 5:29 am

Siegfried wrote:[

von Krogge in his history of GEMA (the company that designed SeeTakt) says that design of the 120kW modulators was complete in 1942 but that they were used on land based SeeTakt. If they 120kW modulators were ready in 1942 that gives them at least 2 years to perfect them for shipboard use.


Regarding the chronology of the high powered transmitters, von Kroge does not confirm that they were ready for deployment by 1944 (and we know from the March 1944 OKM symposium transcripts that they had indeed not been deployed at that time):

By mid 1943 the development of the transmitter module Gisela with high powered tubes was completed. This allowed power on the g band (Seetakt) to be extended to 125 -150 kilowatts. In combination with a partial increase in antenna area where this was possible, led to to ranges with shipboard sets of up to 60 km depending on the size of the target ship.


But it was not a simple matter of installing the module into existing radar sets, because other important features of the radar would not work properly with anode modulation.

It was difficult to make clear to the Navy and Luftwaffe that introduction of new radars with appreciably greater range by means of high power transmitters could take place only after considerable development and testing. von Willisen, who was assigned to operations with Naval Group West was especially exposed to challenges because of the ever increasing losses at sea. He undertook the introduce into operation in his sector much sooner than expected the new powerful transmitters, some still laboratory models. ... shortly before the Normandy invasion....In October 1944 the new set was released for production....


Their were two vexing problems when applying high power gained through anode modulation to the GEMA radars that caused delays. First the fine ranging panel relied on phase coherence which was obtained by a master oscillation coordinated through a central impulse geraete which keyed the control grids of the transmitter triodes. With anode modulation, coherent operation was at least partially lost:

...but the demands for better resolution with the (fine ranging panel) could not be met with such correction circuits and GEMA had to retreat from their high standards of accuracy. In all sets (such as FuMO26) where high power modulators were not necessary the (fine range panel) remained sufficiently precise. Ranges determined with anode modulation (such as FuMO34?) accomplished with low scatter thyratrons were satisfactory for exact gun laying (did he mean "not satisfactory" ?). For larger ranges that could only be obtained with high transmitter power (sets for which is was not possible to increase the antenna size it sufficed to read the range from the CRT with out recourse to the (fine ranging panel). GEMA fulfilled this requirement the new range measuring device "paris". The transmitter pulse triggered a linear time base, which was independent of the fluctuations that caused the time scatter... The well proven (fine ranging panel) had to be replaced by linear time bases, which were triggered by transmitter pulses that were no longer related in phase to the master (oscillation). ...The results of this work which already led to a prototype in summer 1944....


The problem (circa 1944) of suitable range measuring circuits not being available led to the decision to use standard (output) transmitters...


The second vexing problem was that the pulsing net work for the anode modulation was not reliable:

Its (the anode modulation network using thryraton pulsers) weakness was in the transformer that raised the voltage of the modulator pulse. GEMA hoped that one of the high voltage institutes that had research grants would find a solution to inhibit failures of this component, which resulted from insulation breakdown.


GEMA was not unique in encountering these problems. The British and Americans did as well. By 1944, both GEMA and the British (with Type 274) had decided to dump the thyratron pulser method altogether, and instead went to a spark gap modulator. With a spark gap modulator, GEMA's high power transmitter module using Siemens TS60 triodes produced 400 kilowatts output. However, the fine ranging system would not work at all with this method, because of the spark timing scatter.

In summary, it is not at all clear if the high powered sets were deployed aboard warships before the end of the war. Nonetheless, FuMO26 was capable of highly accurate gun laying against enemy ships, using the latest fine ranging system with an accuracy of 25 meters, out to 40 km, and it was deployed before the end of 1943.
Last edited by Dave Saxton on Fri Dec 30, 2016 5:39 am, edited 1 time in total.
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: Tirpitz' Radar

Postby Siegfried » Fri Dec 30, 2016 5:32 am

Dave Saxton wrote:
Siegfried wrote: Could a FuMO 26 have picked up a squadron of Lancasters at 150km?


Most likely. We have a base line for Seetakt picking up aircraft from the Dec 1939 air raid against the Wilhelmshaven anchorage. Seetakt picked up the bombers at 113 km. At that time the power output for Seetakt was only 2 kilowatts and the antenna did not operate in common mode. The 4 fold increase in power in 1940 increased typical range attainment 20%. FuMO26 used an extra large antenna that operated in common mode. We know from primary documents that the FuMO26 antennas increased typical range an additional 30% with the same 8-9 kw power output from the transmitters.

We also have actual data of Seetakt range attainment while using the high powered transmitters from May 1944 tests of the prototype modules.The range to ships exceeded 40 km (some sources list 50 km to a battleship for FuMO34) and to aircraft the range exceeded 200 km.

However, Tirpitz probably would not have been operating FuMO26 prior to the air raid that destroyed it during Nov 1944. By that time Seetakt was almost exclusively used for fire control. Tirpitz was equipped with FuMO81 Berlin search radar sets with PPI indicators and also a Hohentwiel or a Sophie radar stepped on the foremast which would be better for air warning than Berlin. Either Hohentwiel or Sophie could easily reach 150 km to aircraft.


I was under the impression that the Wellington Bomber raid on the Wilhemshaffen naval base was detected by a GEMA Freya radar (2.4m wavelength) rather than GEMA SeeTakt(80cm) The Luftwaffe operated Freya was operational at the time though I imagine the Kriegsmarine had sets.

Both radars were in operational service and I would expect both to have picked up the raid.

I know what Berlin (German PPI microwave) radar is and I know Hohtenweil (50cm PPI) but what is "Sophie"?

The lack of 120kW modulators might have left the Germans vulnerable to broadband noise jamming and for blind fire control that the extra power was essential to spotting shell splash at long range. (shell splash spotting must be important, perhaps it was Duke of Yorks advantage in the ballet of North Cape with Scharnhorst in part due to more output power but also due to her bigger 14 inch shells vs Scharnhorsts 11 inches).

Improved SeeTakt for a Battleship may not have been a priority. Detecting, tracking and targeting bombers must have been a priority for the Reich and the Luftwaffe while for the German navy warning U-boats of maritime patrol aircraft another. Telefunken had a 160kW modulator for its Wurzburg but it also did not enter service.

For instance the Freya based FuMO 391 "Lessing" 100kW warning radar for U-boats would have been most important as it could be used underwater.

The lack of a small search radar for Torpedo Boots (small 900 ton German mini destroyers), S-boots and Minesweeper escorts was of overall more importance than improving FuMO 26. (Note the Italian Navy mounted FuMO 26 on its destroyers whereas the Germans only got them into battleships and heavy cruisers). Hohtenweill addressed this but only belatedly.


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