The pioneers of radio in Poland were army officers. These were Poles who served in the German, Austrian and Russian armies in the World War I. In the fall of 1918, shortly after the war, these experts started organizing Polish radio. On November 4, 1918, in Kraków, a field station, previously used by the Austrian army, sent the first Polish radio signals. Soon, more field stations – this time German — were captured by the Poles in Warsaw and Poznań. Obviously, at first radio was used for military purposes only. Knowledge of Polish experts in this field was used to a great effect during the 1920 Polish-Soviet War. In 1924 radio in Poland was no longer in the domain of the army. In April an Act of Parliament was passed that, among other things, legalized buying, selling, and operating radio equipment by private citizens and businesses; on October 10, the Minister of Industry and Trade issued regulations that set out conditions of obtaining broadcasting licenses and running radio stations. Soon after, an experimental station was opened by Polskie Towarzystwo Radiotechniczne. Polish radio and its expansion In August 1925, bids were invited for the organization of a nationwide radio network. The winner was Polskie Radio S.A., managed by Zygmunt Chamiec. On April 18, 1926, they started to broadcast regular programs. The first station was located in Warsaw and the equipment was an English Marconi Wireless. It was soon replaced by a more powerful unit, with 10 kilowatts output. The old equipment was moved to Kraków. Later on, Warsaw's station was expanded and five new studios, located at Zielna Street, were commissioned. During the following years, Polish Radio S.A. opened new stations in other main cities across the nation. These included: 1927 - Kraków and Katowice 1928 - Wilno (see: Polish Radio Wilno) (This was established at the beginning of 1928) 1928 - Poznań (This was established in mid 1928) 1930 - Two additional stations in Lwów (see: Polish Radio Lwów) and Łódź were added. Also, during the same year, a temporary station called Warsaw II was established. On May 24, 1931, a new transmitter, located at Raszyn near Warsaw, was commissioned. Having the power of 120 kilowatts, it was the strongest transmitter in Europe. At the same time, Polskie Radio increased power of stations in Wilno and Lwów to 16 kilowatts. Further stations were opened in Toruń (1935), a permanent station