ABSTRACT
Shortly after the end of World War I two Potsdam students discovered a common interest in wireless telegraphy and telephony. Paul-Gu¨nther Erbslo¨h, born in 1905 in Du¨sseldorf, came to Potsdam in 1917 through the transfer of his father, a high-level state official. Hans-Karl Freiherr von Willisen, born in 1906 in Berlin-Charlottenburg, grew up in a Prussian officer’s family and studied with Erbslo¨h at the Realgymnasium in Potsdam. After the war von Willisen, by way of an intermediary friend of his parents, came into possession of a Type E 170 intermediate-receiver of the German Telephone Company (DE-TE-WE). During the war this receiver had been part of an Army wireless station and allowed earphone reception in the 600 to 150 m band (500-2000 kHz). Not only that, young von Willisen received a box that was richly filled with AEG and TKD triodes and many other radio and military components, which impelled him and his friend Erbslo¨h toward intensive electronic activity.
