During the whole time of the Czechoslovak Republic’s existence, Ministry of National Defence was fighting with Ministry of Post and Telegraph for the competency concerning issuing concession and control over the radio communications. In spite of the facts that the technical equipment enabling monitoring of the transmission of illegal radio stations was in hands of the Ministry of National Defence, the Ministry of Post and Telegraph became winner of the competence disputes. Imperfection of both the civilian and military direction finding receivers was proved in 1934, when German emigrant Formis, M.Sc., started an illegal anti-Nazi transmission from the restaurant Na Záhoří by Slapy. Fruitless effort of the Czech institutions to find the transmitter ended only after killing the Formis by German commando. With regard to the response to this case, they established a specialized workplace – Radio Technical Control Service in the middle of the thirtieth. It was to search for illegal radio stations. Gradually, they established the services in Brno and Košice. It is a paradox that the only discovered station at the beginning of the year 1937 was the agency radio station of the advanced agency centre of the 2nd Division of the Main Command providing the communication between Litoměřice and the Main Command. Activity of the Radio-Electric Control Service culminated in the period of mobilisation in September 1938. The well equipped network of the army monitoring and direction finding stations, operating within the practice radio telegraph stations which monitored namely the operation of military radio stations out of the territory of the Czechoslovak Republic, was much more successful.