A 1950s era New York City subway advertisment for WNYC by Amelia Opdyke Jones, a.k.a. "Oppy". Oppy was the cartoonist  behind a twenty-year run of subway posters and advertisments beginning in 1946.

The figure pictured here is Father Knickerbocker, a fictional character historically used to represent New York City much like Uncle Sam represents the United States.  The Subway Sun, a placard 'newspaper,' was often a lesson in subterraean equiette admonishing riders to not to litter or spit. Oppy's work has been chronicled on several sites, among them: Subway Art Blog and Forgotten NY Subways.

Note: WNYC-AM's frequency shifted over the years. It began at 570 kilocycles (kc), and then moved to 810 kc, 830 kc and finally settled at 820 kc in 1990.