Radio contacts realistic?

[msalama]

Right-o then, please help a Kaleun out and answer this

For the life of me I just can't understand how the hell is it that my radioman is able to locate ships, etc. and then draw them on the map with the gear he has at his disposal! Well of course one can get a _bearing_ to a radio transmitter whenever its RF power stage is switched on and it radiates around on its carrier frequency, but that IMO should be all if triangulation is not used... So how exactly, pray tell, does the guy do his mojo majik and tells me its exact location, course, speed, etc. with just a SINGLE FRIKKIN' CONTACT?

OK, granted, you can draw some conclusions from the signal strength too - i.e. is the source most likely nearby, or is it in all likelihood further away - but even that's kind of fuzzy, because the effective radiating power of the transmitter is something you don't know!

So what exactly is it, then? Do I have a magician aboard here, and if so, should I dismiss him straight away before he bloody goes and h3XXes us all?

[Canovaro]

Kaleun,

It is not a radar contact. It is a message from sources like other uboats, loose lips or even secret agents about location, course and speed, coming in via the radio.

[Puster Bill]

The answer, my friend, is the Beobachtungsdienst. That was the Signals Intelligence unit that intercepted, DF'ed, and broke the messages of the merchant marine, and then passed them on to the Kriegsmarine.

This intelligence was used, at least on occasion. For instance, the B-Dienst would intercept a message. It would send the information to BdU, who would transmit it to the boats at sea. A famous example is when Reinhard Hardegen was told he could divert from his course to attack the Dimitrios Inglessis if he was within a certain distance of her. She had reported a rudder problem.

History supports me, too. Looking at the BdU KTB, you see reports like this:

III. Reports on the Enemy:
a) 1) U 160 reports sinking of petrol tanker "Gallia" (9,974 BRT) in ED 9946.
2) U 84 sighted convoy in DM 1896, course 320, speed 8 knots, air patrol 1.
b) None.
c) U-boat sightings in CA 56 - CA 52 - DN 84 - DN 91 - DD 85 - DD 18 - DC 15 - DD 78 - BB 79.
U-boat attack in DM 16/24 - DC 12 - DD 78.
English aircraft sighted U-boat in BF 75 - 72.


I believe the IIIc section is intercepted enemy communications. The sections are:

a) Reports from u-boats
b) Reports from german aircraft
c) Reports from the B-Dienst
d) Reports from the "German Intelligence Service".

You can actually see in that excerpt that the Germans are reading the U-boat situation reports put out by the British. It helps to know what the other guy knows about you...

So I rationalize it as intercepted communications being relayed to me, but my radio operator (Bernard, naturally) forgets to tell me about them.

[Jimbuna]

On thr other hand...it could well be a magician

[Sailor Steve]

Originally Posted by Puster Bill

You can actually see in that excerpt that the Germans are reading the U-boat situation reports put out by the British. It helps to know what the other guy knows about you...

Peter Padfield, in his book War Beneath the Sea, makes the observation that the British were happily congratulating themselves on their cracking of the German codes, but it never seemed to occur to them that the enemy might be reading their mail as well. Hubris is a lovely thing.

[flag4]

Originally Posted by jimbuna

On thr other hand...it could well be a magician

these mahoogaflips of yours get better and better :rotfl: :rotfl:

put them in a box and send them to me - i want to play - its my turn !!

[Jimbuna]

Originally Posted by flag4

these mahoogaflips of yours get better and better :rotfl: :rotfl:

put them in a box and send them to me - i want to play - its my turn !!

LOL

[Jimbuna]

Originally Posted by Sailor Steve

Peter Padfield, in his book War Beneath the Sea, makes the observation that the British were happily congratulating themselves on their cracking of the German codes, but it never seemed to occur to them that the enemy might be reading their mail as well. Hubris is a lovely thing.

Possibly the closest the British came to giving away the fact they were reading the German codes was in early to mid 44 when the Admiralty sunk the tanker Charlotte Schliemann in the Indian Ocean where she was meant to refuel Monsun boats, despite explicit orders from the British Government not to.

Enter the last ressuply tanker Brake.....

[Sag75]

Hi! look at this interesting article:

http://www.uboat.net/articles/id/51


good hunting!

[msalama]

No no no gents, I'm not talking about radar contacts and radio reports received from B-Dienst, but HF/DF contacts (HF/DF = high frequency direction finder) just as described in the abovementioned u-boat.net article (thank you for the link).

But anyway, I was perhaps a bit hasty in my judgement of the poor guy and his allegedly supernatural capabilities in defining the target's speed, etc. based on a single contact, because what he obviously does is that he receives multiple contacts from the same source first and then of course uses them all in defining the target's status! It's just that the game doesn't indicate this in any way... D00H

That aside I _still_ think the guy's a bit über, because IRL using passive RF technology there'd be no way of defining the target's location without resorting to triangulation, i.e. using 2 receivers and their relative bearings-to-target to calculate a position. Thus I'm still inclined to think I've someone aboard here who needs to be treated with utmost courtesy, lest he gets pissed off and then curses us all

[Puster Bill]

Originally Posted by msalama

No no no gents, I'm not talking about radar contacts and radio reports received from B-Dienst, but HF/DF contacts (HF/DF = high frequency direction finder) just as described in the abovementioned u-boat.net article (thank you for the link).

But anyway, I was perhaps a bit hasty in my judgement of the poor guy and his allegedly supernatural capabilities in defining the target's speed, etc. based on a single contact, because what he obviously does is that he receives multiple contacts from the same source first and then of course uses them all in defining the target's status! It's just that the game doesn't indicate this in any way... D00H

That aside I _still_ think the guy's a bit über, because IRL using passive RF technology there'd be no way of defining the target's location without resorting to triangulation, i.e. using 2 receivers and their relative bearings-to-target to calculate a position. Thus I'm still inclined to think I've someone aboard here who needs to be treated with utmost courtesy, lest he gets pissed off and then curses us all

Actually, it's a fairly trivial exercise if:
1. The U-boat is moving
2. The target isn't
3. The target transmits more than once.

In that case, it's like two different stations DF'ing the target.

It's more complicated if you are both moving, but not impossible. If the target transmits twice, and is traveling in a known shipping lane, you can make some pretty accurate assumptions based upon your known position, course, speed, and the bearings of the two or more different transmissions from the same target.

How do you know those two transmissions came from the same target? As far as I know, merchant shipping didn't encrypt or otherwise obscure callsigns back in WWII, so that would be one clue. Even if they did, it would probably be on some kind of rota, so that for example the SS Spotted Dick would be assigned the callsign GES one day, and GXW the next, and so one for a 30 day period. Make two transmissions in a day, and they would have to use the same callsign both times.

Another would be particular fist(s) of the operator(s) on that vessel. Trust me, the way an individual sends Morse, especially with a straight key, is as unique as their voice. Any operator worth his salt would be able to distinguish between vessels by distinguishing between the fists of their operators.

The whole problem with all of this is while it is possible, it generally wasn't done. The radio operators on u-boats didn't generally have time to scan around and listen for enemy transmissions, they were listening for messages from BdU, and perhaps beacon signals from other u-boats or maritime patrol aircraft.

So really the best answer is that they are from land-based signals intelligence sources (DF, codebreaking, etc.) that are transmitted by BdU to you. The operator isn't "uber", he's just presenting the data he received from BdU, who received it from the B-Dienst. This "explanation" works exceptionally well up until June of 1943. That is when the British, having been alerted through their own codebreaking success, changed their main naval code.

Even after June of 1943, it would still work reasonably well because by then the Germans know, for the most part, all of the shipping lanes the British are using, and while they can't read the reports of position, heading, and speed, they can make very reasonable assumptions based on DF work (which gives you the position) and prior knowledge. It is sometimes spooky how accurate traffic analysis can be.

If I had my druthers, I would have the game engine re-written so that instead of showing up on a map, the information would be presented to you in the form of a radio message, and you would have to plot it yourself. I wouldn't mind getting those messages, instead of the "historical" ones describing how Horcht Myclothes in U-3.14159265 is having engine troubles. While I was at it, I'd have the option of getting them encrypted, and have to decrypt them using an Enigma simulator.

/Ex 05H Signals Intelligence Morse Interceptor.
//Can order a beer in several languages
///Usually the wrong one.

[difool2]

I'm still toying with altering the detection %s for each ship, convoy, and task force so that you get a realistic (however I finally determine that) chance to generate a contact (presumably from other subs, planes, or intel). Right now you get virtually no convoy contacts outside a miniscule radius of a couple hundred km, but just upping that (opportunity contacts radius) to something much larger gives you far too many. That will be a big chore tho, even with the tools I found on this forum which will help (some), but I might do it.

[msalama]

Thank you for your opinions and insights gents.

@Bill: Indeed. I stand corrected. Never thought of doing it the way you describe, but see no reason why it shouldn't work

@Difool: Is that a mod you're working on? If so, then please keep us posted - sounds interesting and useful

S!