In the first phase of the war, the communication means of the Nation´s Defence were provided namely by radio amateurs and former members of telegraph troops. Signal group of the Nation´s Defence headed by Colonel GS Stepan Adler and Captain Karel Divina concentrated the wireless operators from former Central of Training Radio-electric Stations in Prague specialized to radio monitoring and direction finding (detection) before the war. The group succeeded to acquire about twenty radio stations from the radio amateurs and from the production of Microphona Company. Several radio stations were transported also from Great Britain via Poland. Maintaining of permanent communication with the home resistance movement required two-side, high-quality technical equipment. At the beginning, thanks to the immense effort of the soldiers from the Nation´s Defence, the communication was surprisingly better on the side of the home resistance movement. On March 14, 1939, they had no radio station for maintaining the communication with home on the board of the aircraft which transported the Chief of Reconnaissance Group of the 2nd Division of the Main Headquarters Colonel GS Frantisek Moravec.