Bismarck's radar

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Francis Marliere
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Bismarck's radar

Post by Francis Marliere » Mon Oct 18, 2010 4:13 pm


I am reading "Bismarck" by Bercuson & Herwig, and I am surprised that the authors quote German radars (Bismarck's FuMO 23 and Prinz Eugen's FuMO 27) as radar detectors and not as search radars. It's the very first time I read that since every other sources quote this sets as search and fire control radars. I am not inclined to believe the authors since there are a few factual errors in the book (such as a 8" shell weighting 500 lb) but since I am by no way an expert on naval radars I am in doubt. Could you please tell me the truth ?

Thanks for your help,

Francis Marliere

Thorsten Wahl
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Re: Bismarck's radar

Post by Thorsten Wahl » Mon Oct 18, 2010 8:38 pm

the Seetakt Fumo 23 and 26 were able to be used also in a passive mode called FUMB - Funkmessbeobachtung
prerequisite enemy radar was using the observed frequency
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Dave Saxton
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Re: Bismarck's radar

Post by Dave Saxton » Mon Oct 18, 2010 8:57 pm

Bismarck and PG both were equipped with GEMA FuMG40G active radar sets. Later on these were designated FuMO27. (500PRF and 8-9kw = FuMO27, not FuMO23)

FuMO27 had a typical BB to BB range of ~30,000 meters (32,800 yards), a range accuracy within 50 meters (1941). At the time of Bismarck's operation it was usually used for ranging and search at sea, but this model did have a highly capable lobe switching capability.

The receiver section would not normally be used to detect enemy radar pulses because it was a coherent radar system with the transmitter and receiver precisely coordinated by a central impulse geraete (the receiver also used two exact IF frequencies: with a stable local osscilater and a coherent LO). The receiver and transmitter also had to be in tune to the same wavelength, so unless the enemy was using the exact same wavelength, and pulse timing/pulse marking, the reciever would likely not pickup enemy radar.

It's likely that Bismarck and Prinz Eugen had dedicated passive radar detection gear (although they did not have the specific passive antenna gear installed a few weeks later on their sisters) seperate from the active radar gear.
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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