WHYN-TV originally operated as a primary CBS affiliate with a secondary affiliation with DuMont; it lost DuMont when that network folded in 1956. During the late-1950s, it was also briefly affiliated with the NTA Film Network. It moved to channel 40 on September 30, 1957 in order to give the station a closer dial position to other UHF stations in the region. However, in 1958, WTIC-TV (channel 3, now WFSB), a station in the nearby Hartford market that had previously been an independent station, switched to CBS, prompting WHYN to petition the Federal Communications Commission (FCC) unsuccessfully for a VHF channel; in 1959, channel 40 became an ABC affiliate. WTIC-TV then became the CBS affiliate of record in Springfield; over the years, channel 3 would block several attempts by channel 40 to switch from ABC back to CBS.