Radio contacts realistic?

[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.