WFIL is immediately adjacent to sister station WMCA (at 570) in New York City, and the two stations have similar histories: both were Top 40 stations in the 1960s, both underwent a format evolution as AM radio faded as a music medium, and both have a Christian/religious format today. WFIL and WMCA are both 5,000-watt radio stations, but each one puts less than 5 kW of power in the specific direction of the other, because they are located next to each other on the dial, and are not allowed, by the Federal Communications Commission (FCC), to interfere with each other. Both stations also maintained Call For Action telephone help lines, being among the first radio stations in the United States to do so. The telephone number of WFIL's Call For Action line was GReenwood 7-5312. (Under the present-day North American Numbering Plan, the primary telephone numbering plan in the United States, this number would have corresponded to (215) 477-5312.)