On November 10 1945, KQW (the predecessor call letters to KCBS Radio) aired a live production celebrating "25 Years of Broadcasting" as the radio industry marked a quarter-century since the first government-licensed broadcasts on KDKA/Pittsburgh and WWJ/Detroit. Of course, KQW/KCBS roots ran deeper, traced to the 1909 broadcasts by Dr. Charles Herrold in San Jose.

This audio file, courtesy of the California Historical Radio Society,  includes that 1945 broadcast as well as an introduction delivered in 1975 by Paul Cortland Smith, who was the engineer for that 25th Anniversary production.