German Admirals Examined a Captured Radar — Then Realized Why Their U-Boats Were Disappearing

On the night of January 30, 1943, six British bombers crossed the German coast carrying a device that had never been used in combat. It was smaller than a suitcase. At its core lay a piece of machined copper resonating at frequencies no engineer in Germany believed an aircraft could carry. The device was called H2S. Three nights later a Short Stirling returning from Cologne was shot down near Rotterdam. Its set was pulled from the wreckage almost intact. In the weeks that followed, senior officers of the Kriegsmarine gathered around a table in Berlin and stared at that small metal box. What they were looking at, though they did not yet realize it, was the reason their U-boats had begun to vanish from the Atlantic. (0:00) The device had been born three years earlier at the University of Birmingham. In February 1940, John Randall and Harry Boot completed a working cavity magnetron—centimeter waves at power levels hundreds of times greater than anything else in the world. A radar built around it could fit inside an aircraft and paint coastlines, ships, even buildings. Britain classified it at the highest level and, in September 1940, carried one to the United States. Germany produced none. German physicists had concluded such tubes were not practical for airborne use. (1:20) While the magnetron moved into mass production, Admiral Karl Dönitz’s wolf packs were sinking more than 700,000 tons in a single month. Coastal Command’s meter-wave ASV Mark II began catching boats in the Bay of Biscay. The answer was Metox—the wooden Biscay Cross that warned a commander in time to dive. By the end of 1942 every operational U-boat carried it. Dönitz trusted the shield. That same night he became Commander in Chief of the Kriegsmarine, Pathfinder Force flew the first H2S sets toward Hamburg. Metox could not hear them. (3:10) This is the story of the copper cylinder pulled from a Dutch field—and of the wavelength that made the surface of the Atlantic uninhabitable. 👻 Welcome to WW2 Phantom! Step into the shadows of World War II and discover untold stories, forgotten heroes, legendary battles, and the human experiences that shaped history. Every episode is inspired by real historical events and brought to life through immersive storytelling. Thank you for watching and supporting WW2 Phantom! Your views, comments, and support help us continue sharing powerful stories from the past. 👍 If you enjoyed this video, please Like, Share, and Subscribe for more incredible WW2 stories. 🔔 Subscribe here:    / @ww2phantom   💬 We'd love to hear your thoughts! Leave a comment below and let us know which World War II story you'd like to see next. 📩 Business Inquiries: Email: [nguyenngoads@gmail.com](mailto:nguyenngoads@gmail.com) #WW2 #WorldWarII #MilitaryHistory #HistoryDocumentary #warstories #WWII #WW2History #MilitaryHistory #BattleOfTheAtlantic #UBoat #USNavy #Navy #Radar #H2S #Magnetron #Germany #Atlantic #Dönitz #CoastalCommand #RAF #Veteran #Biography #History #Documentary #Aircraft