Bismarck radar detector

[wadinga]

Hello Hans,

Indeed, Dave Saxton teased us with this

*Finally, I have discovered evidence that the Bismarck likely had another specialized device aboard which could have detected radar, but I can not talk about it at this time.'"

many years ago, but nothing more has emerged other than speculation. How tantalising these mysterious suggestions are!

Koope and Schmolke say Lutzow was equipped with Timor antenna and Samos receiver when she emerged from repair in 1942 but nothing about any ECM system corresponding to the Funkmess document in 1941.

All the best

wadinga

[hans zurbriggen]

Hello Mr. Wadinga,
I agree. It's curious that after so many years and so many experts that have studied this ship, there are still 'secrets' surrounding Bismarck (and German radars in general). I hoped someone here could have new info, after Mr. Saxton's 2013 veiled hint.

I read somewhere (don't have a link) that 1941 'Timor' based system could detect wl's from 75 to 300 cm, while the document mentions 50-200: this is another very puzzling aspect. Tirpitz received Timor, Sumatra and related receiver (not sure it was the same 1942 'Samos' as final 'Samos' from Rhode-Schwartz should have been able to detect wl's from 64 to 333 cm in 1942, that is frequencies from 90 to 470 MHz, see picture) already in summer 1941. Lützow was already installing new system in June 1941.

hans

samos.png (100.54 KiB) Viewed 1282 times

[wadinga]

Hello hans,

Such systems were pretty secret at the time, so there is limited information, especially for big ships. There is much more information available for U-boat installations.

The Metox FuMB ! receivers were volume produced by a Parisian company called Grandin, a manufacturer of domestic radios, based on a German military design. They were paired in U-boats with the FuMB Ant 2 "Honduras" antenna (Biscay Cross). The earlies date I have seen for their introduction in U-boats is August 1942. The antenna was later replaced by the FuMB aAnt 3 "Bali". Although some sources vaguely say 1940? for the start date of the Metox programme, it surprises me that U-boats that are far more exposed to radar illumination danger than German surface vessels which spend most of their time in harbour, should not see the first example until mid 1942! It seems to me that converting an original idea into a practical production line item, especially for manufacture in an occupied country, means late 1941 is a more realistic date.

The FuMB Ant 7 "Timor" appears to be an antenna only designation, and installation in Lutzow as early as suggested (mid 1941) would be the first installation as even the ships trapped in Brest only received theirs in early 1942. Many sources suggest the Timor and Samos combination was only installed in her 1942 refit after the second torpedoing.

It cannot be denied the document makes no reference to a dedicated detector in Bismarck.

All the best

wadinga

[hans zurbriggen]

Hello Mr. Wadinga,
very few doubts Lützow was already installing Timor antenna in mid 1941 (Tirpitz received Timor by Sept. 9). Question is which was receiver used with Timor antenna at that time, because standard 'Samos' receiver (see picture above) was manufactured only in 1942 (it was identified as RS 1/5 UD/42, where 42 stands for production year).
Document (http://www.kbismarck.com/funkspruch-flo ... tjens.html) mentions a system able to detect 50 to 200 cm wl's but I doubt it could, because later 1942 'Samos' was still unable to go under 64 cm.

Regarding Bismarck's mistery, I do not think Lütjens would have sent 3 messages (13:26, 21:32 on may 24 and 09:12+ on may 25) stating that enemy actually had radar if Bismarck had not somehow detected them (based only on intelligence). Receiver could have already been same as Lützow, but antenna was surely not Timor (it could have been Sumatra, much less easy to see in photo, as Mr. Saxton suggested).

hans

[Herr Nilsson]

Regarding Bismarck's mistery, I do not think Lütjens would have sent 3 messages (13:26, 21:32 on may 24 and 09:12+ on may 25) stating that enemy actually had radar if Bismarck had not somehow detected them (based only on intelligence). Receiver could have already been same as Lützow, but antenna was surely not Timor (it could have been Sumatra, much less easy to see in photo, as Mr. Saxton suggested).

I quote myself:

...The crux of the matter is Skl/Chef MND had the leading role in regard of the allocation of radar detectors. It's very unlikely they had no information about such a device on board Bismarck, but they do not mentioned it in this document at all...not a single word. Why is it not mentioned, whereas they are discussing almost all possible aspects of the matter? ...

[hans zurbriggen]

Hello Mr. Nilsson,
no answer to your question, just thoughts: possibly, NVK had installed a 'prototype' secret device (as per Mr. Saxton hint), that other KM commands had no need to know ? Even a 'simple' adapted receiver taking signals from WT antennas ?
Do you have answers to my questions:
1) why was Lütjens (13:26, 21:32 on may 24 and 09:12+ on may 25) so sure enemy had radar without detecting it (against Brinkmann's conclusions) ?
2) why did Gruppe West ask (2:38 on may 25) Lütjens to report British radar frequency, if he had no way to detect radar emissions ?

hans

[wadinga]

Hello All,

I think we can resolve these matters, to a degree.

Herr Nilsson is correct, the creators of the "wash-up" document would surely be party to knowledge as to whether there was a "proto-Metox" aboard Bismarck. It makes no mention of this. But Hans' point that Lutjens was directly requested to discover the frequency used is also true. I believe this is how these two points can be reconciled.

From the document it is clear that most interception work on the German side was from the English Channel, where the RAF-operated radars which had aided fighter interceptions of the Luftwaffe were very long wavelength units. The Kriegsmarine had adopted relatively long wavelength units for the FuMO series. so the expectation for radars aboard RN vessels was that they would also be in the 1 to 2m area. I believe SKL merely hoped Bismarck could identify British radar frequencies by using FuMO sets in a listening mode to detect expected frequencies close to their own operating bands. The British could do this, and unless we have evidence that the FuMO couldn't this seems likely.

They seem to have been completely unaware that Type 284 would use frequencies very similar to the Luftwaffe's current Wurtzburg specialized gun laying radar, ie around 50cm. As has been observed, the Kriegsmarine didn't get a receiver capable of picking up such transmissions until the FuMB 5 "Fano" of 1943.

There was no direct report of intercepting RN radar signals by Lutjens, and I believe he merely inferred its use because Suffolk tracked him so successfully through all kinds of poor visibility. The "wash-up" document wastes a great deal of time (IMHO) considering Brinkmann's completely unwarranted notion that the British had a long range passive hydrophone system whose performance surpassed even the wildly-overstated results from PG's own GHG. Numerous examples of false alarms and even imaginary torpedo attacks were under-stated in the "glowing" report of GHG's usefulness.

However, the speculation that Bismarck was intercepting British radar transmissions stems from the appalling gaffe of transmitting and retransmitting Lutjens' long-winded report, repeatedly breaking radio silence for several hours after Suffolk had actually lost contact. There iis no actual evidence Bismarck ever picked up any British radar transmissions. The interceptions of these radioed lost contact reports by B-Dienst units either ashore or in PG is available in the archive on the site, so the question is whether Bismarck's unit, which had unnerved Lutjens with reports that shadowers were following his every move, suddenly failed to pick up any of these later transmissions. Lutjens' transmitted assertion that he was still being shadowed by a battleship and two cruisers at 07:27 makes little sense to those using hindsight. SKL knew the British had lost contact and might have sent this vital information to the Flottenchef. It was a major tactical blunder by him and his staff to assume that the shadowers were still in contact unless there was positive evidence that they were. This blunder was, of course, negated by an equally serious British blunder in misplotting the D/F bearings in Tovey's flagship and sending the hunters off in entirely the wrong direction.

All the best
wadinga

[hans zurbriggen]

Hello Mr. Wadinga,

you write:"I believe SKL merely hoped Bismarck could identify British radar frequencies by using FuMO sets in a listening mode to detect expected frequencies close to their own operating bands. The British could do this, and unless we have evidence that the FuMO couldn't this seems likely."

SKL could hope so but we know it was not the case: Prinz Eugen Em II 'receiver' could get nothing (despite PG radar was proving more reliable than BS one during the whole mission).

If Bismarck detected British radar emission (imho very probable, due to Lütjens firm and repeated conclusions, opposite to Brinkmann ones, having the same info) she did not with Em II receiver (FuMO used 80 cm wl), as British radars used 50 cm wl (Type 284) or >= 1,4 meters wl's (Type 286, 280, 281, 79, 279 etc), neither picked up by a FuMO antenna.

Lütjens adamant message, 08:01 on may 24 (reported in KTB at 13:26), says: 'enemy radar devices' not 'probable enemy radar (or sonar) devices' or 'intelligence of enemy radar devices'.

hans

[Thorsten Wahl]

With regard to Funkmess it must be said that
any mention of the term or properties that allow conclusions to be drawn was strictly forbidden in open systems. Since even encrypted radio communication does not have to be regarded as secure communication in the sense of gkdos. The term DT 350 hm i would consider as
a term that could be mentioned in an unsafe medium.
Disclosing the frequency of enemy Funkmess would allow conclusions to be drawn from funkmess = radar = dete = em2=RDF

Even in fairly secret Wardiaries the term Funkmess was strictly forbidden. FUNKMESS protocols were alway separate documents.

[wadinga]

Hello Hans

Lutjens would be making a perfectly reasonable assumption in asserting that the British vessels had radar, since his own ships had a device which could do what they were doing, identifying contacts' relative range and bearing through darkness, fog and snow. He has no need to imagine other ways in which the British could be tracking his ships. He would have been sure that RN radar must come, since British radar had been so effective a year before in the Battle of Britain. The Kriegsmarine had deployed shipborne radar years before, the Brits would catch up sometime.

Brinkmann has other ideas. In his paean of praise for GHG performance, Brinkmann not only imagines the British have an equal or better system in their ships, but additionally invents a shore-based system on the Icelandic coast which forewarns patrolling ships at the western end of the Denmark Strait. See Page 30 of the KTB. His imaginings go even further because having admitted a passive sound bearing gives no range, he than fantasizes the two shadowers working together to derive a triangulation of bearings to determine enemy position. Without knowing an accurate baseline distance, and at over-the-horizon ranges? His simplistic comparison with U-boat hunting fails to grasp the British are using active sonar (ASDIC) and thus get ranges.

Brinkmann's over-fulsome praise for GHG just muddies the waters, and confuses the wash-up documents' conclusions. Lutjens knew the enemy had radar because it could only be radar and that is what he reported. What Brinkmann very sensibly points out is that active radar can give your position away, so he was no fool.

All the best

wadinga

[hans zurbriggen]

Hello Mr. Thorsten,
thanks for info. Secrecy is the main problem we face even today trying to understand what was on board Bismarck.

Hello Mr. Wadinga,
while I follow your reasoning (based however on what we know from Suffolk report), the British radar presence on board was not known with certainty and the SKL document shows how confused Germans had been about this point (sonar or radar were equally probable for them).
Lütjens would not have stated (early in the morning of 24) that there were actual ' enemy radar devices' if not 100% sure. You know very well how careful are navy officers to submit their opinion to admiralty, using words like 'possibly', 'probable', 'suggestion', 'intelligence', etc. Suffolk lost contact during the 23-24 night during dark hours: there was only the attempt in the evening to catch SF by surprise to point to presence of British radar on SF.
Lütjens is not using any dubitative form: this strongly implies (imho) Bismarck was equipped with some radar detection device, actually receiving British emissions as per Mr. Saxton 2013 post. We now know that in June Lützow was already installing a 'standard' receiver (still not identified here in terms of code-name) for Timor (and Sumatra ?) antennas, to be deployed to the whole KM large units shortly: why should have BS sailed without any (possible 'prototype' of this) equipment ?

hans

[wadinga]

Hello Hans,

Relating to the precision of Lutjens' reports,
"UHR 07:27 Quadrant AK55. One battleship and two heavy cruisers are continuing surveillance."

He had no evidence of this at all. None of these ships had been seen and identified since the previous day. Even if he had been detecting radar transmissions with an as yet unidentified system, it could not identify the types of ships transmitting them. This report clearly reflects Lutjens' assessment and was, as we know now, completely inaccurate. The mystery is why he believed this. Hans Henning von Schultz, when reconstructing the Bismarck KTB chose to believe, against the evidence he himself had collated from British radio signals, "That the stalking was not severed is verified.....Page 151 of the KTB. It was clearly impossible to accept in 1941 that Lutjens and his staff had made such a silly mistake in breaking radio silence with a wordy, badly coded/transmitted and repeatedly copied version of an unnecessarily detailed report without a very good reason. The imagining of an effective "proto-Metox" aboard the vessel is an explanation thought up by subsequent authors to attempt to explain the inexplicable, The document we now have sight of makes no mention of such a device, whilst revealing very sensitive information about British transmission frequencies. So it is likely the security clearance for receiving this document would be high enough to allow knowledge of "proto-Metox" if it existed.

Therefore it is perfectly reasonable to assume that Lutjens just made an educated guess that radar and not some imaginary esoteric technique was being used to track him through snow, fog and the short Arctic night and to direct carrier air attacks against him.

All the best

wadinga

[hans zurbriggen]

Hello Mr. Wadinga,
an educated guess would not have have been expressed (3 times, starting 08:01 on may 24) with such certainty (choice of more dubitative and cautious words) and Gruppe West request to report British wl's confirms it (possible emissions heard via FuMO antenna had wl close to 81 cm, no need to ask for them).
I think Mr.Saxton 2013 conclusions are more credible. Germans had passive radars since 1940 and were installing them on Lützow and Tirpitz in summer 1941, I think it's very probable BS got something experimental (and/or at least a team able to use WT normal or U.K. antennas coupled with a dedicated receiver) on board in may.

hans

[wadinga]

Hello Hans,

I see your opinion has hardened somewhat from your post of 23rd October:

while Lütjens message implies Bismarck was receiving enemy radar emissions.

to

to Lütjens would not have stated (early in the morning of 24) that there were actual ' enemy radar devices' if not 100% sure

I concur with Herr Nilsson, who quoted PG's FuMO being used in detector mode and his conclusion, based on the document, that there was no "proto-Metox".

You know very well how careful are navy officers to submit their opinion to admiralty, using words like 'possibly', 'probable', 'suggestion', 'intelligence',

Such concerns did not inhibit Brinkmann from pure speculation about British long range passive sonar and presenting it as fact. The "wash-up document" is clearly completely misdirected by this, and British intelligence would have been cheered to think time was wasted on this dead end. GHG did not protect Scharnhorst or Lutzow and Hipper from being surprised in the Barents Sea nor even keep track of Bismarck when she disappeared out of PG's visual range.

BTW looking at pictures in Koop and Schmolke of Lutzow emerging from repair and refit in Kiel in April 1941 there seems to be no sign of a Timor antenna on the rear face of the rengefinder, whereas on her emergence a year later after another refit and repair it is quite obvious. Can you point to a reference for installation in 1941?

This has been a valuable discussion, occasioned by the adding of even more excellent archive material on this valuable site.

All the best

wadinga

[Steve Crandell]

It's quite possible that when Bismarck was illuminated by a British radar, her radio operators would hear interference on certain frequencies, and the logical conclusion would be the enemy was using radar.