 The Allied bombing air raids over Berlin intensified in 1943 and Franz moved to Schuttertal, then, after 1945, to Lahr, in the Schwarzwald region of south-western Germany.The logo of an 'arrowhead' was chosen as a symbol of the passage of an electric signal in an electronic circuitry.After the war Franz, in co-operation with the ‘Rundfunktechnisches Institut’, (‘Broadcasting Technique Institute’) directed by Walter Kuhl, designed the ‘927 Large Studio turntable'.