Complex sentence: The station has always been a CBS affiliate, but also maintained a secondary affiliation with ABC until WPTA (channel 21) signed on in September 1957; during the late-1950s, WANE was also briefly affiliated with the NTA Film Network.
Split into simpler sentences: The station has always been a CBS affiliate, but also maintained a secondary affiliation with ABC until WPTA (channel 21) signed on in September 1957. During the late-1950s, WANE-TV was also briefly affiliated with the NTA Film Network.