1 April – The rumor that Hitler is dead sweeps the United States, as millions of CBS radio listeners hear the Führer cut off in mid-speech during a shortwave relay of his address at the dedication of the German battleship Tirpitz in Wilhelmshaven.[1]
15 July – Inauguration of DZRH, one of the oldest radio stations in the Philippines.
29 July – In France, with war on the horizon, a package of decrees tightens the state's control of public radio and obliges all private stations to broadcast, unedited, the government's Radio-Journal in place of their own news programmes.[3]
7 August – Official test transmissions begin from Radio Andorra. The station is ceremonially inaugurated two days later by the French Minister of Public Works, Anatole de Monzie.
September – The French government's radio for schools initiative ends until 1946.[4]
1 September – At 18.55 local time BBC engineers receive the order to begin closing down all UK transmitters in preparation for wartime broadcasting: this marks the end of the National and Regional Programmes of the BBC. At 20.15 local time the BBC's Home Service begins transmission: this will be the corporation's only domestic radio channel for the first four months of World War II.
6 September – U.S.-born William Joyce makes his first broadcast for German radio, reading the news in English.[7]
18 September – English-language propaganda radio programme Germany Calling is first broadcast to the United Kingdom on medium wave nominally from Reichssender Hamburg station Bremen (via the coastal Norddeich radio station) and by shortwave to the United States. In today's London Daily Express, pseudonymous radio critic Jonah Barrington nicknames the station's English-speaking broadcaster "Lord Haw-Haw". He is probably referring to German playboy journalist Wolf Mittler, who makes a few such broadcasts, but the name transfers to cashiered British Army officer Norman Baillie-Stewart (dismissed in December) and then to American-born William Joyce, with whom it is most associated. Baillie-Stewart and Joyce hold U.K. passports at this time, rendering themselves liable to prosecution for treason.[7] The station also plays jazz music, prohibited on German domestic stations.
19 September – Popular British radio comedy show It's That Man Again with Tommy Handley is first broadcast on the BBC Home service, following trial broadcasts from 12 July.[8][9] Known as "ITMA", and also featuring Jack Train and many others, it runs until Handley's death in 1949;[10] the performers have initially been evacuated to Bristol.
21 September – WJSV broadcast day: Radio station WJSV in Washington, D.C. records an entire broadcast day for preservation in the United States National Archives.
6 November – Hedda Hopper's Hollywood debuts on radio in the United States with gossip columnist Hedda Hopper as host; the show runs until 1951, making Hopper a powerful figure among the Hollywood elite.
17 November – Radio station ZQI begins broadcasting in Jamaica, initially for an hour a week.[11]