Tirpitz' Radar

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Dresden
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Re: Tirpitz' Radar

Postby Dresden » Sat Dec 08, 2012 9:20 pm

so the 26 used a 3x6 mattress?

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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Sun Dec 09, 2012 2:05 am

Yes. Actually, according to Trenkle they were 6.5 x3.2 m, so if your building a model or something keep that in mind. In the documents they just use round numbers referring to them as the 6x3 m common mode antenna.
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.

Dresden
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Re: Tirpitz' Radar

Postby Dresden » Sun Dec 09, 2012 2:42 am

Just what I needed to know. Thank you.

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Re: Tirpitz' Radar

Postby Dresden » Mon Dec 10, 2012 12:33 am

There's a 1/350 PE German naval radar fret that has a 26 with ears. In reading another post by you in this forum, you believe you stated that because of the larger mattress of the 26 it had 4 rows of dipoles and this didn't need ears. As you might imagine I am a bit confused. Would you please clarify this?

Thanks

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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Tue Dec 11, 2012 7:44 pm

Dresden wrote:There's a 1/350 PE German naval radar fret that has a 26 with ears. In reading another post by you in this forum, you believe you stated that because of the larger mattress of the 26 it had 4 rows of dipoles and this didn't need ears. As you might imagine I am a bit confused. Would you please clarify this?

Thanks

Don't put too much meaning in the FuMO numbers. They didn't exist until 1944 and was applied retroactively. They are not chronological. The FuMO26 with the owls ears installed on Prinz Eugen is not quite the same as the 6x3 antenna mattress radars installed on TP. The earlier installation on PG was actually Flak Leit G. The FuMO number later assigned to it was FuMO201. The ears allowed for lobe switching on the vertical plane so it could determine the elevation of an aircraft target for Flak firecontrol. The big 6x3 mattress didn't need ears because it used the phased array scanning principle on both the vertical and horizontal planes- being common mode and horizontally polorized. The earlier model radars needed the owls ears to locate the height of aircraft because they were shorter and not common mode.
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.

alecsandros
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Re: Tirpitz' Radar

Postby alecsandros » Tue Dec 11, 2012 8:51 pm

Dave,
Is there any info available on the kind of radar used by Tirpitz in her 1941 combat trials in the Baltic ?
And, most interesting, is there any source mentioning the use of integrated radar control during those trials, with some metrics attached... ?

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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Wed Dec 12, 2012 3:04 pm

There were two seperate trials. The first one was in June 1941 (which really calls into question the notion of TP being on Rhine Ubung). During the June shoots TP's radar suite was incomplete with no aft radar, or even the optical rangefinder, fitted. The June shoots showed up defects in the Gunnery and firecontrol systems, so the TP was sent back to the dock yard to have these addressed during July and Aug. I don't know the details of the defects. The second gunnery trials was in Sept 1941. When TP returned from the dock yard the radar fit was revised. There was a new DeTe haus fitted ontop of the foretop position and it now had the FuMO27's fitted to all three large rangefinders. Moreover, the FuMO27's had the additional equipment fitted to the receiver arrays for lobe switching, indicating blind fire capability. The direct data transfer from radar to the firecontrol systems was a feature of the 1940 radar models (FuMO27).

You will not find such detailed records pertaining to radar. It was simply forbidden in most cases by the strict secrecy protocols. Many of the technical records of Naval Ordnance Command were kept at Kiel and were destroyed by Allied bombing. Most of the KM personal who knew such details were killed during the bombings. Some of the OKM records were kept at Berlin and survived the war but these records are not that detailed. Private records kept by various commands and private firms were ordered destroyed at the end of the war. Some GEMA/KM records did survive but are in the hands of private indviduals now. The reason they survived was because von Willisen simply kept many of them in the boot of his Mercedes, and nobody thought to look for them there. But more importantly, his private secretary, Frau Rhein, saved them or knew where they were located and turned them over to von Kroge in the 1960s after von Willisen's death. On the Prinz Eugen documentation and manuals were provided to the USN technical personal but they declined to even look at them, and did not take them.
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 alecsandros » Thu Dec 13, 2012 6:20 am

Many thanks for a most detailed reply, Dave!
I was thinking about the shots on target-ship Hessen. I remember that you posted a while ago that the KGN was very satisfied with the firing's results at ranges up to 25km...

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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Thu Dec 13, 2012 2:45 pm

Marine Arsenal 6 alludes to these shoots. Toebicke said that the shoots confirmed the horizontal spaced array concept worked against long fire. I have some photos of the shoots. It must have been during the Sept trials as TP has its full 1941 radar suite and appears to be probably testing both radar and the optics. The salvo patterns at 25km appear to be well grouped.
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 alecsandros » Mon Dec 17, 2012 9:15 am

Dave Saxton wrote:Marine Arsenal 6 alludes to these shoots. Toebicke said that the shoots confirmed the horizontal spaced array concept worked against long fire. I have some photos of the shoots. It must have been during the Sept trials as TP has its full 1941 radar suite and appears to be probably testing both radar and the optics. The salvo patterns at 25km appear to be well grouped.


Thanks David!

It would be interesting to know also about the bombardment on Spitzbergen - as it was the only time Tirpitz used her 380mm guns in combat...
But from what I know so far, there are very few details of the artillery performance during that raid. I only know that the raid was a success, and the facilities destroyed...

Dresden
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Re: Tirpitz' Radar

Postby Dresden » Thu Jan 03, 2013 5:36 pm

Dave:

Do you have an isometric picture or sketch or something along those lines of a FuMO 26 mattress? I bought a photoetch set of German radar mattresses but if I do have all the bending and assembly correct then the frame is kinda unusual (as well as being a nightmare to assemble!).

Thanks.

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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Sat Jan 05, 2013 3:01 pm

The Hans Galley drawings have a depiction of the FuMO26 reflector screen. You might be able to find these on line or purchase a copy. The USN photos of Prinz Eugen's FuMO26 antenna are the best photo's I know about. However, the resolution is such they still do not show such fine details as the dipoles themselves, or the lens. Depending on scale these fine features will probably not be able to be modelled anyway.
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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Dave Saxton
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Re: Tirpitz' Radar

Postby Dave Saxton » Sat Jan 05, 2013 3:49 pm

Image

This is the FuMO26 Seeart on Prinz Eugen. The number of dipoles were increased from 10 each for send and receive on the standard 4 x2 meter Seetakt antenna to 64 horizontally polarized dipoles in common mode. All 64 were used for both send and receive. Doubling the numbers of dipoles of an array antenna increases the antenna gain by a factor of four. In this case it would increase gain by a factor of 6.5 squared compared to the older Seetakt!

Also seen in the photo is the FuMO81 Berlin radome at the head of the foremast and the Sumatra passive antenna for a Fano receiver on the front of the foretop railing.
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.

Christian VII.
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Re: Tirpitz' Radar

Postby Christian VII. » Sun Jan 18, 2015 11:56 pm

Just out of interest:

How good was German FC radar in terms of range & bearing accuracy in comparison to British & US FC radar in the following periods?:

1940-41
1942-43
1944-45

And just for fun, how would the Tirpitz have compared with the USS Iowa in a long range shoot off in late 1944?

Steve Crandell
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Re: Tirpitz' Radar

Postby Steve Crandell » Mon Jan 19, 2015 6:04 pm

I think that would be a very tough call. I wouldn't give either ship a significant advantage.


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