Bismarck radar detector

[Herr Nilsson]

hans,

of course they had passive capability. Radar consists of sender and receiver. The receiver is the passive part. Prinz Eugen searched for enemy radar with her own radar set:

Der Kommandant des Kreuzers "Prinz Eugen" hat gemeldet, dass keine britischen Deteimpulse aufgenommen worden sind; das bestätigt jedoch - da keine anderen Beobachtungsgeräte an Bord waren - nur, dass etwa vorhandene britische Dete-Geräte nicht in der Nähe der deutschen Em II-Welle arbeiten.

The question was asked on May 25th at 00:47 and it wasn't answered in the famous long message or any other message after. That most probably means they had no independent enemy radar detector, but just their own radar receiver like Prinz Eugen.

[dunmunro]

Hello Mr. Wadinga,

you have written: 'it seems to me section D2 of the Funkmess document describes a new general service detector system to be developed/installed'

your understanding is correct: Lützow was already receiving this new 'passive radar/antenna', but I do not understand which system it could be: the document speaks about detectable wl's from 50 to 200 cm, but we know (thanks to Dave Saxton : https:https://www.kbismarck.org/forum/viewtop ... 222#p78222) that German passive radar receivers (including 'Timor') were unable to pick up wl less than 60 -80 (depending on models) until 1943 end, thus conceding an advantage when British were using Type 284 (50 cm).

Hello Mr. Dunmunro,
according to Ellis, Type 284 was the most useful radar during Bismarck shadowing. Metric radars were probably used as well and I guess these are the radars Lütjens refers to in his message. Question is still which kind of receiver was used on board Bismarck to detect these metric enemy radars.

hans

Type 281 was designed to be a multi-role radar; WA, WS, GA, and GS. It had much better surface range than the Type 279, at the expense of a lower high altitude detection range. AFAIK, amongst the ships that engaged Bismarck only PoW had one, and unfortunately it appears to have failed during PoW's initial engagement with Bismarck. It had a surface detection and ranging capability similar to the Type 284.

[hans zurbriggen]

Hello Mr. Nilsson,
thanks, I see your point that is very much in line with Mr. Saxton observation (first underlined), but I disagree with your conclusion.
Mr. Saxton was skeptical about FuMO usage to detect British radars and Brinkmann confirms no radar had been detected anyway using Em II, while Lütjens message implies Bismarck was receiving enemy radar emissions. Therefore Bismarck was not using only FuMO 27 to detect emissions. What was she using ?
I am wondering whether in these 8 years any new info had surfaced regarding Mr. Saxton 'discovery' re. Bismarck detection system (second underlined):

Dave Saxton wrote (my underlined): 'Did Bismarck have an alternative radar warning receiver to a Metox or Samos in may 1941? The answer is, yes, it could have. B-dienst had more capable radar warning receivers available. B-dienst's or the NVK's equipment were more capable than either the Samos or the Metox but these equipment were only available in small numbers. (B-dienst even logged a detection of 10cm radar in late 1941) But Bismarck didn't need a specially designed radar detector such as a Metox to detect British radar during 1941:
*The regular wireless comunucations receivers could have detected the transmissions of Type 79, 279, and 281.
*The more specialized talk between ships receivers could detect decimetric radar pulses if tuned to the right frequency.
* It has also been reported that Bismarck's FuMO27 radar receivers could have been used in listen only mode, but I'm rather sceptical that this would be done. The FuMO27 used a special tuning module which kept the receiver module perfectly aligned with its associated tramsmitter. The earlier models had missed detections in the past because of frequency misalignment between transmitter and receiver
*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.'

Hello Mr. Dunmunro,
thanks, also Type 281 was metric (wl 3,5 meters); I don't see any of the British radars at DS (284, 279, 286, 281, etc) having a wl close enough to FuMO 27 one (around 80 cm) to be picked up.
Thus my question still stands: how did Bismarck detect British radar emissions (as per Lütjens message) ?


hans

[Herr Nilsson]

Did she „feel“ radar emissions anyway?

[hans zurbriggen]

Hello Mr. Nilsson,
Lütjens message implies she did. Else Lütjens conclusions would have been same Brinkmann wrong ones (usage of sonar).

hans

[Herr Nilsson]

What message?

[hans zurbriggen]

"Vorhandensein Dete-Gerät beim Gegner, Reichweite mindestens 350 hm beeinträchtigt Operationen im Atlantik in stärkstem Masse. Schiffe wurden in Dänemarkstrasse in dichtem Nebel geortet und nicht mehr losgelassen. Loslösung misslang trotz günstigster Wetterbedingungen."

[Herr Nilsson]

Lütjens didn’t need any detector to come to this conclusion. Every move he made was reported within minutes.

[hans zurbriggen]

Hello Mr. Nilsson,
Brinkmann concluded it was British sonar to keep contact and reported no enemy emission detected. Why did Lütjens come to other conclusions ?
His message is strongly pointing to Bismarck detecting enemy radar emissions.

hans

[Herr Nilsson]

Brinkmann didn't consider the possibility of British radar at all. Lütjens and his staff came to another and much simpler conclusion.

[hans zurbriggen]

Hello Mr. Nilsson,
imho, 'simpler' explanation why Lütjens came to different conclusions is Bismarck detected British emissions.
Request from Gruppe West to report their frequencies confirms presence of radar detection equipment/skill on board. No similar request to Brinkmann.

hans

[ede144]

Hello All,

I wholeheartedly agree with Hans, the message inbound to Bismarck clearly indicates it was hoped her crew could detect and analyze the frequencies of British radars received by some system aboard ship. It may have been imagined that the British were using frequencies close enough to the FuMo systems for them to be used in listening mode, but we know Type 284 was using a much shorter wavelength. However, other British systems, including the aircraft-mounted ASV and the Type 286 derivative of this used in Norfolk, used longer wavelengths (1.5m) which FuMo may have been able to detect. Metox was designed around detecting these longer wavelengths, was deployed in U-boats much later, and often triggered premature crash dives at ranges where the aircraft could not possibly detect the submarine. As such it was frequently counter-productive.

It might still be that such transmissions detected in Bismarck convinced Lutjens' staff they were still being "painted" by British radar and that it it was safe to send the "long-winded" report. Using primitive internet translation it seems to me section D2 of the Funkmess document describes a new general service detector system to be developed/installed, but that does not preclude a prototype aboard Bismarck.

The discussion on the later Samos receiver in the Tech section shows it had two major modes: simple detection and direction finding. In detect mode it may have picked up a broader band of frequencies, for the latter it required to discriminate frequency more accurately.

Captain Ellis mentions using another radar system in Suffolk, Type 279 in listening mode.

I believe the B-Dienst detachment were purely concerned with intercepting and decoding wireless Morse transmissions of text at conventional radio frequencies.

It would be interesting to get an accurate translation of the Funkmess document.

All the best

wadinga

From above mentioned document:
Erfahrung des Einsatzes an der Kanalküste hat gelehrt, dass es dem B-Dienst ohne Mühe gelingt, einen vorgenommenen Wechsel der Ortungswelle zu erkennen und den Störsender folgen zu lassen.

It explains that B-Dienst did search for Radar Signals and
trie's to work with Thema, like determine ist's position and disturb IT.

[Herr Nilsson]

Hello Mr. Nilsson,
imho, 'simpler' explanation why Lütjens came to different conclusions is Bismarck detected British emissions.
Request from Gruppe West to report their frequencies confirms presence of radar detection equipment/skill on board. No similar request to Brinkmann.

hans

Prinz Eugen was already detached.
So what device detected British emissions in your opinion?

[wadinga]

Hello All,

Hi ede 144. As I read it the B service is involved in detecting British very long wavelength land based radars with land based installations on the French coast. In the D section paragraph it says that shipboard radio/radar officers will be trained for the new radar interception installation in Lutzow. I think it would be a serious security weakness if those who knew how to decode British signal traffic were part of the ship's ordinary complement. Brinkmann specifically complains that his ship has been allocated a smaller B-Dienst detachment, specially brought onboard for the mission, than Bismarck received.

Hi Hans, thanks for correcting me about Timor, indeed it was a separate, smaller mattress-type either rotating by being fixed to the rangefinder tower or later on its own separate pole. Palau was much the same. Sumatra was a series of antennae fixed to the superstructure, facing in different directions. Since the Metox receiver was designated FuMB (Funkmeßbeobachtung)1 it is difficult to envisage what a predecessor might have been other than an experimental unit.

It seems rivalry between companies GEMA and Telefunken may have been a factor in not looking for British 50cm radar. GEMA concentrated on the longer wavelength radars for marine use based on the original Seetakt, but also developed the similar Freya for Luftwaffe use. Their rival had apparently dismissed the concept earlier, but went off on their own route developing the Wurzburg radar using 50-60cm wavelengths for AA gunnery for the Luftwaffe. Concentrating on the longer wavelengths for Kriegsmarine use, it seems like the shorter ones like the Type 284 used were overlooked, so creating a detector for them was delayed.

Shore based B-Dienst had noticed Suffolk's shadowing reports (based on radar) had dried up many hours before it told Lutjens, after Bismarck had broken radio silence with several unreadable repetitions of the "Long Message". If Herr Nilsson were correct and the only indication of British radar tracking were these intercepted reports, the B-Dienst teams at sea messed up very badly in not noticing they had stopped and informing Lutjens they might be clear of the shadower and strict radio silence should be enforced.

All the best

wadinga

[hans zurbriggen]

Hello all,
I see all your points but question is still the same: what was used aboard Bismarck to detect enemy radar emissions ?
We know Prinz Eugen used Em II (FuMO) antenna, detecting no emission.
Lütjens messages (13:26 (PG was not detached yet), 21:32 on may 24 and 09:12+ on may 25) + Gruppe West request (02:38 on may 25, all hours from BS KTB) imply (imho) that Bismarck actually detected radar emissions (I have no clue with what). This old post from Mr. Saxton (from 2013) listed possible devices (common or specialized, excluding Metox and Samos standard installations), but it looks like nobody has any new/better info to supplement it:

Dave Saxton wrote: "Dave Saxton wrote: 'Did Bismarck have an alternative radar warning receiver to a Metox or Samos in may 1941? The answer is, yes, it could have. B-dienst had more capable radar warning receivers available. B-dienst's or the NVK's equipment were more capable than either the Samos or the Metox but these equipment were only available in small numbers. (B-dienst even logged a detection of 10cm radar in late 1941) But Bismarck didn't need a specially designed radar detector such as a Metox to detect British radar during 1941:
*The regular wireless comunications receivers could have detected the transmissions of Type 79, 279, and 281.
*The more specialized talk between ships receivers could detect decimetric radar pulses if tuned to the right frequency.
* It has also been reported that Bismarck's FuMO27 radar receivers could have been used in listen only mode, but I'm rather sceptical that this would be done. The FuMO27 used a special tuning module which kept the receiver module perfectly aligned with its associated tramsmitter. The earlier models had missed detections in the past because of frequency misalignment between transmitter and receiver
*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.'"

hans