Locating U-boats through their radio transmissions

U-boat radio transmissions could expose positions in the Atlantic and allow convoys to be routed around them. Germany is described as underestimating Britain's ability to detect and triangulate those signals. The large number of British listening posts and the use of warships as additional receivers are offered as reasons for that advantage. Recognizable operator habits supplied another kind of clue. Tracking how and where an operator transmitted could help reveal the movement of people or commands without reading the message.