On Sunday, March 30, 1941, many radio stations changed frequency because of the North American Regional Broadcast Agreement (NARBA).
The move was meant to reduce congestion and interference on the airwaves. In those days WPOP was known as WNBC and it was located at
1380 kilocycles on the AM dial. Under the terms of NARBA, WNBC would move up the dial to a wavelength of 1410 kilocycles. This "Moving Day"
ad was published in The Hartford Courant on Sunday, March 23, 1941.

For listeners, this meant reallocating or relabelling of the push buttons on their home radio sets. Listen to this sample advertisement produced by
the Radio Corporation of America a clever way to get people to call their RCA serviceman!