In Germany, the development of the first technologies of sonar and radar were interrelated. Following Christian Hulsmeyer's forgotten invention of the "Telemobiloskop" in 1904, two Berlin engineers, Paul Gunther Erbsloh and Hans-Karl von Willisen, developed and built devices to locate targets accurately by reflections with underwater sound and radi
Translator's preface. Foreword by Paul Gunther Erbsloh. Introduction. In the beginning was an idea. The originators. An irresolute beginning. The incorporation of GEMA. The first underwater sound and radar equipment. DeTe- and S- equipment. First surprises. Drop the magnetron, pick up the triode. A radar success with aircraft. Things move forward. Year of decisions. The beginning of production. The time just before the war. GEMA is bound to armaments. War does not stop research. Hard but successful years. Turbulent times. On the way to powerful radar and sonar. Intensification to the limit. GEMA's constrained ending. Translator's epilogue. Sources. Index of names. Index of subjects.