In 1937 a government committee recommended that not everyone need answer every census question (the start of sampling), that some questions be dropped (e.g. literacy), and that questions on mobility, education, and employment be asked on the 1940 census. The new 1940 questions (including new income and fertility questions) were opposed by many, including Senator Tobey of New Hampshire who advised the American public to boycott the Census!!! For the first time the Census Bureau established their own Public Relations unit, and countered these negative attacks with a massive public relations program leading up to the enumeration. As part of this publicity program. an 8 part series of radio broadcasts ("Uncle Sam Calling"), prepared by the Office of Education with help from the Census Bureau, were sent to radio stations, to be played one episode a week starting the week of February 11th, 1940. Joel Weintraub has episodes 1 and 2 on a 16" transcription record (and subsequently as MP3 files), and has made text transcriptions (Feb 11, Feb 18) as well as a short audio clip of two parts from the introduction of the radio announcement.
Feb 11 transcription
Feb 18 transcription
short audio clip
[Note: In a trial census in two counties of Indiana in 1939, a
question was asked about whether the family had a radio (as they did on
the 1930 census), but that question was dropped and did not appear on the
1940 population schedule. Joel Weintraub]