> Recognising the importance of radio in disseminating the Nazi message, Goebbels approved a scheme whereby millions of cheap radio sets (the Volksempfänger) were subsidised by the government. In the "Radio as the Eighth Great Power"[114] speech, Goebbels proclaimed:
> It would not have been possible for us to take power or to use it in the ways we have without the radio....It is no exaggeration to say that the German revolution, at least in the form it took, would have been impossible without the airplane and the radio. ...[Radio] reached the entire nation, regardless of class, standing, or religion. That was primarily the result of the tight centralization, the strong reporting, and the up-to-date nature of the German radio....Above all it is necessary to clearly centralize all radio activities, to place spiritual tasks ahead of technical ones,...to provide a clear worldview,
> By the start of the Second World War, over 70% of German households had one of these radios, which were deliberately limited in range in order to prevent loyal citizens from considering other viewpoints in foreign broadcasts.[113] Radio broadcasts were also played over loudspeakers in public places and workplaces.[113]
https://en.wikipedia.org/wiki/Propaganda_in_Nazi_Germany
> During the democratic period, when the Weimar government introduced progovernment political news, the growth of Nazi popularity slowed down in areas with access to radio. This effect was reversed during the campaign for the last competitive election as a result of the pro-Nazi radio broadcast following Hitler’s appointment as chancellor. During the consolidation of dictatorship, radio propaganda helped the Nazis enroll new party members. After the Nazis established their rule, radio propaganda incited anti-Semitic acts and denunciations of Jews to authorities by ordinary citizens. The effect of anti-Semitic propaganda varied depending on the listeners’ predispositions toward the message. Nazi radio was most effective in places where anti-Semitism was historically high and had a negative effect in places with historically low anti-Semitism
https://academic.oup.com/qje/article-abstract/130/4/1885/191...
Remember that before radio the best you could get was newspapers and leaflets, and both were mostly ignoring the lower strata of society. In religious regions you could also make a deal with the church I guess, it was the only information network that reached masses regularly.
People in countryside don't get leaflets. Poor people don't spend on newspapers. Radio was "free newspaper everyday", and Nazis gave the radios for free.
Also when you buy a newspaper you presumably already agree with its message at least a little, so it's hard to make people change their minds with newspapers. When you buy a radio you get all the stations, so you can be persuaded by them to change your mind over time.