Blohm & Voss BV 246 Hagelkorn for anti-shipping guidance system questions

[Stuka_Hunter]

Hello

Recently I read something about Blohm & Voss BV 246 Hagelkorn and figured out one projected use was anti-shipping. It got me curious as to which guidance system could be used against ships, since:

-Unguided attacks would be to inaccurate for a moving target
-Kehl-Strasbourg was jamed and unusable
-Wire guidance was to risky for the mother plane

There was a projected variant to home in on the Allied radar, the Radieschen which was fairly accurate when it worked properly (2 meters near the target), but was never used operationaly.

Could it be possible to home in on the onboard sonar or some other piece of electric equipment?

 

[Jemiba]

Sonar ?? I think, that not even today you could home on a sonar (sound emission) without a sensor
in/under water.
Other electrical equipment ? Maybe, during operation Igloo White in Vietnam the USAF was able to
detect and locate trucks with unshielded ignition systems. Such systems in a way produce radio
signals, principally in the same way, that was used in the very beginning of radio communication.
in this paper https://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwip56Sewa3UAhUIElAKHSI-CMAQFgg3MAI&url=http%3A%2F%2Fwww.dtic.mil%2Fdtic%2Ftr%2Ffulltext%2Fu2%2Fa394935.pdf&usg=AFQjCNF-SP6Z7b6fKr5dXXxQ7v670UQ8Mg
detection range is given as 100 to 200 meters ....
Other electric devices can produce radio interferences, too, but I don't think, that they could be located from much
longer distances. If your neighbour uses a lousy electric razor it may well interfere with your radio reception,
but probably not in the next block of houses...

 

[_Del_]

Jamming wasn't 100% effective, and not every convoy was so equipped. They could have shifted to random frequencies over a greater range, fairly easily. Use multiple antennae to discriminate signal direction (ie from the launching aircraft and other transmitters).

Wire guidance was used by the Hs 293. Did they not also look into electro-optical? Short step away from IR. Active or semi-active homing was introduced by the US in the same basic time frame in the Pacific. Not impossible.

 

[Jemiba]

Quite interesting reading with this regards :
"Warriors and wizards : the development and defeat of radio-controlled glide bombs of the Third Reich" by Martin J. Bollinger.
Successes and limitations on both sides are shown very well. E.g., when the principles of the German glide bombs already were
known to the allies during the first phase of its use, it nevertheless sometimes was diffcult to equip even just one convoy escort
with a jammer.

 

[Stuka_Hunter]

Sonar ?? I think, that not even today you could home on a sonar (sound emission) without a sensor
in/under water.
Other electrical equipment ? Maybe, during operation Igloo White in Vietnam the USAF was able to
detect and locate trucks with unshielded ignition systems. Such systems in a way produce radio
signals, principally in the same way, that was used in the very beginning of radio communication.detection range is given as 100 to 200 meters ....
Other electric devices can produce radio interferences, too, but I don't think, that they could be located from much
longer distances. If your neighbour uses a lousy electric razor it may well interfere with your radio reception,
but probably not in the next block of houses...

I am looking for a system that can detect a device on the ship at a a minimum range of 10 kilometers, which would protect the mother plane. And i dont think electric razors is what the Hagelkorn would home onto.

Jamming wasn't 100% effective, and not every convoy was so equipped. They could have shifted to random frequencies over a greater range, fairly easily. Use multiple antennae to discriminate signal direction (ie from the launching aircraft and other transmitters).

Wire guidance was used by the Hs 293. Did they not also look into electro-optical? Short step away from IR. Active or semi-active homing was introduced by the US in the same basic time frame in the Pacific. Not impossible.

I agree on the fact that it wasnt 100% effective, but British Type 650 system was able to jam the reciever of the Henschels Hs 293 directly, regardless at which frequency it was operating. Same went for Fritz X.

There was the Hs 293 D version which was television guided, but was it was unsuccesfull at testing stage.

 

[_Del_]

The 650 worked because the IF was uniform. It seems like a relatively small amount of effort would produce a broader range of frequenciese resulting in a much more difficult proposition to jam. Varying the IF would have frustrated the 650.
I'm not sure what the flight time would be, but it would constitute no small feat to identify and jam either the command or IF frequencies from among a broad band in thr time allotted.

 

[Stuka_Hunter]

The 650 worked because the IF was uniform. It seems like a relatively small amount of effort would produce a broader range of frequenciese resulting in a much more difficult proposition to jam. Varying the IF would have frustrated the 650.
I'm not sure what the flight time would be, but it would constitute no small feat to identify and jam either the command or IF frequencies from among a broad band in thr time allotted.

So, could it be possible to jam the Hagelkorn Radieschen locked onto a ground radar? And lets say they have half a minute to react, if they spot it in time.

 

[_Del_]

It was a passive seeker, yes? Not an active one, like say the BAT. I would say it'd be possible to decoy a passive head (or just stop radiating). I'm not sure how you'd "jam" a passive seeker. Maybe with enough radiated energy to burn out the receiver?

Still, the 30 seconds you've allotted is a small window to identify the threat and enact countermeasures. Not impossible, but it goes quick.

I'm tempted to order that Bollinger book

 

[Stuka_Hunter]

It was a passive seeker, yes? Not an active one, like say the BAT. I would say it'd be possible to decoy a passive head (or just stop radiating). I'm not sure how you'd "jam" a passive seeker. Maybe with enough radiated energy to burn out the receiver?

Still, the 30 seconds you've allotted is a small window to identify the threat and enact countermeasures. Not impossible, but it goes quick.

I'm tempted to order that Bollinger book

So actually you would be able to target an anti-aircraft radar on the ship. If that would be possible, could the following options be possible:

-program the missile so that it hits a little lower that the radar and hits the main ship compartments.
-missile emits a radiowave before it hits, that would be picked up by a submarine, which would attack the ship Hagelkorn hit.
-3 missiles target 3 individual ships and not home in on one radar on one ship.

Hmm I might read the book as well.

 

[_Del_]

-- possibly? One difficulty would be determining where exactly the transmitter is in 3d space. Passive is just giving a direction, not a distance.
-- why not just have the launching aircraft relay the ships position or HF/DF to the sub?
-- It would probably depend on the frequency (-ies) and the azimuths. I'm not sure.

 

[Stuka_Hunter]

-- possibly? One difficulty would be determining where exactly the transmitter is in 3d space. Passive is just giving a direction, not a distance.
-- why not just have the launching aircraft relay the ships position or HF/DF to the sub?
-- It would probably depend on the frequency (-ies) and the azimuths. I'm not sure.

Thank you for the answers

 

[_Del_]

Quite interesting reading with this regards :
"Warriors and wizards : the development and defeat of radio-controlled glide bombs of the Third Reich" by Martin J. Bollinger.
Successes and limitations on both sides are shown very well. E.g., when the principles of the German glide bombs already were
known to the allies during the first phase of its use, it nevertheless sometimes was diffcult to equip even just one convoy escort
with a jammer.

I was able to finish this yesterday, actually. Each of the systems deployed prior to early 1944 were capable of jamming only an individual frequency, and there was no way to coordinate in a timely manner among the equipped escorts. The highest number of escorts so equipped in an engagement prior to Feb 1944 appears to be three. Which means if nine glide bombs were launched, a maximum of three were capable of being jammed. It required the manual interception of the signal and manual tuning of the jamming equipment to same.
The location of the antennae on the Hs 293 made jamming from the frontal quarter difficult. The ideal location for the escort jamming was between the glide bomb and the attacking aircraft. This was difficult when the most frequent use was against picket escorts and stragglers.
The USN decided against jamming the intermediate signal (as the RN did successfully with the type 650) because it was adjudged to be too easily side stepped by a change of the IF, which the Germans did not do operationally but was entirely within their capabilities.

Only one in nine glide bombs launched and observed to be responsive to control hit targets. Including mechanical failure, interception, etc, the number falls to one in twenty-four glide bombs leaving German airfields were adjudged to hit their targets.

Alot of technical problems would've been shared by the BV 246 (mulitpath interference, weak signal strength at maximum operational [hence frequently terminal phase] distances, stalls during aggressive maneuvering).

Overall the jamming was not considered effective, especially early. Disappointed that they gave only a brief discussion of EO and wire guidance which were both developed but never operationally deployed.