Television in 1941
Germany hosted the 1936 Summer Olympics at Berlin. These games were televised by two German firms, Telefunken and Fernseh, the using RCA and Farnsworth equipment, respectively. This marked the first live television coverage of a sports event in world history. Both systems broadcast at 180 lines and 25 frames per second. Four different areas were telecast using three cameras. In total, 72 hours of live transmission went over the airwaves to special viewing booths, called "Public Television Offices" in Berlin and Potsdam.
(remember the video that the aliens sent back in Sagan's Contact? (Jodie Foster Movie))
Roosevelt spoke at the opening session of the New York World's Fair on April 30, 1939. It was the first time a presidential anything was televised, but it was a demonstration of the potential of the technology and hardly could be considered broadcasting, as there were only a handfull of tvs in the country.
FDR's fireside chats and addresses were broadcast by radio.
Truman's speech on Oct. 5, 1947 was the first presidential address broadcast from the White House.