experiments were also being conducted using the newly developed vacuum-tube transmitters, which were capable of making audio transmissions. Included as part of this work was a series of test radio concerts. However, upon the entrance of the United States into World War One, effective April 7, 1917 the government ordered all civilian radio stations, including 2YU, shut down for the duration of the conflict. Amateur station 2ADD (1920) After the war, in the fall of 1919 civilian radio licenses began to be issued again, including a standard amateur station authorization with the call sign 2ADD granted to Wendell King at the Union College Electrical Laboratory. The Radio Club was reformed and resumed activities, which included a more organized series of entertainment broadcasts intended to be heard by the local community. The first of these broadcasts was made on October 14, 1920, and a letter dated October 22, 1920 that appeared in the December 1920 issue of the amateur radio magazine QST announced that the College would be broadcasting weekly radio concerts "every Thursday evening from 8:00 to 8:30 and from 9:00 to 9:30 Eastern Standard Time, on 350 meters [857 kHz], signing 2ADD". Experimental station 2XQ (1921) An Experimental license, 2XQ, had been issued to Union College in late 1919, and the broadcasts were soon switched to using this authorization. In the summer of 1921, an article featuring the station noted that not only were the Thursday night concerts continuing, but the station had added Sunday night sermons prepared by Union College President C. A. Richmond. The same article also reported that the station, "equipped with the most modern of apparatus", had been heard as far away as 1,200 miles (1,900 kilometers). The Radio Club designed a portable radio for receiving 2XQ transmissions, and as a publicity stunt, mounted it on a baby carriage that was wheeled around town to show off its capabilities. The invention was promoted as "a great pacifier for a younger generation", and received extensive national publicity. Broadcasting station WRL (1922-1924) Initially there were no specific standards restricting which radio stations could conduct a broadcasting service, so it was permissible for stations holding an Amateur or Experimental license to make entertainment broadcasts. However, effective December 1, 1921, the U.S. Department of Commerce, which regulated radio at this time, formally established regulations defining a broadcasting station, setting aside two wavelengths — 360 meters (833 kHz) for entertainment,