When war broke out, Pohl attempted unsuccessfully to volunteer for military service, but was refused for health reasons. His suggestion, together with Erich Regener, to set up and operate privately-funded diagnostic X-ray apparatus in two military reserve hospitals was gratefully accepted. In November 1914, he began cooperating with military radio operators on locating enemy transmission stations; this led to his appointment to a position as Chief Engineer with the rank of Captain on the Board of Transport Examiners (VPK), which he held until the end of the war.