The Turing Bombe. A machine developed by Alan Turing at Bletchley Park to break the German Enigma codes in the Second World War.Margaret Cooper
"There’s a continual traffic from all kinds of messages going in the ether and so you had to concentrate and listen to this particular tone that wasn’t very loud to get that message."
And the supervisor, we had those message pads, message things on the pads and we filled them up with pencil by the way, pencil, copying, copying, copying. However, the thing about the copying is that normally we’re...now because I was never supervisor I really don’t know what’s happening here but from my point of view we were set on a frequency and the frequency, as far as I know, were headquarters, German headquarters. I believe was the name of one of them, I think that it’s one that I saw in October when I was in France just outside of La Rochelle, can’t remember the name of that German headquarters at the time.
Anyway, they were a continual flow of coded messages to their fleet out there and we copied it continually because it was going to be on that frequency that a U-boat was going to have to send his message. So you had to be alert and at the same time you had to copy the messages >cause we had already decoded them. Well, you know, you know that we had broken the naval code very early on so you certainly had to concentrate and listen. And the problem with a U-boat, when it breaks into headquarters message, which was a continual flow, they came out with two distinctive sounds that alerted headquarters ‘I’m a U-boat-- want to talk to you@.
So those sounds stay with you and one was an E-bar I think it was called, it was a dit-dit, da-da, dit-dit. And it sounded like it was coming from underwater. You know, it had that gurgly sound to it. The other one, I believe, was a RPT. I’m not sure, it seems to me that a dit, da-da-da something; anyway, I can’t remember that. But the problem with them is that you may be copying headquarters in its flow at a strength from one to nine, at a strength of eight or seven. However, when the U-boat transmitted, he would be maybe a two or a three transmitting sound. So you had this loud sound coming in over, and all the traffic that’s going on. You know, it isn’t like a radio station. There’s a continual traffic from all kinds of messages going in the ether and so you had to concentrate and listen to this particular tone that wasn’t very loud to get that message.
As soon as you heard the opening: dit-dit da-da dit, you hit a panic button beside your receiver and out in the snowy old field, farmer’s field at Coverdale, there would be other WRENs [a name given to members of the, WRNS, Women’s Royal Naval Service] in a wooden shack in front of a big cathode ray tube swinging around to get to the frequency you’re on and get a bearing and if you know all that business, the bearings were plotted in England.