In May 1940, the Federal Communications Commission (FCC) announced the establishment, effective January 1, 1941, of an FM radio band operating on 40 channels spanning 42–50 MHz.
[2] The first fifteen commercial FM station construction permits were issued on October 31, 1940, including four to New York City applicants.
The Marcus Lowe Booking Agency was authorized for a station at 46.3 MHz,[3] which debuted on June 1, 1942, as the fourth FM broadcaster in New York City, with the call sign W63NY.
[4] Effective November 1, 1943, the FCC modified its policy for FM callsigns,[5] and the call sign was changed to WHNF, reflecting its co-ownership with WHN.
[10] The new designation, recognizing the ownership of the stations by the studio through Loew's, was then adopted in September 1948 by the AM outlet, at which time WMGM became WMGM-FM.