This article focuses on historical dimensions of knowledge creation and transformation by university academics. It explores their often overlooked role in the broadcast output of BBC radio in disseminating knowledge and ideas outside the educational environment, directly into the homes of the audience. Examples of this activity include the Open University, schools broadcasting, armed forces programmes and study circles. The concern here is the less didactic approach encapsulated in radio documentaries, talks and discussion programmes. The central argument is that the meeting between broadcaster, academic and listener via the medium of radio represents a significant, but often forgotten, example of the university's early engagement in a "cultural third mission". Using evidence from BBC radio archives during the two decades after the Second World War, the article considers how knowledge was conveyed by academics to radio audiences through different forms of programming devised to address the changing needs of nation and culture.