First radio stations emerge
Two stations claim to be the first broadcasters: WWJ in Detroit and KDKA in East Pittsburgh. However, they both began broadcasting within months of each other, with KDKA being the most famous for its coverage of the 1920 election results. Their founding represents a shift from amateur radio operators to stations with consistent programming.
(1) Brett Davis, "KDKA: Broadcasting's Pioneer Station | Pennsylvania Center for the Book", Pennsylvania Center for the Book, Penn State Libraries, published Fall 2010, https://www.pabook.libraries.psu.edu/literary-cultural-heritage-map-pa/feature-articles/kdka-broadcastings-pioneer-station.
(2) "WWJ (AM)", Wikipedia, accessed December 7th, 2019, https://en.wikipedia.org/wiki/WWJ_(AM).