channel 7 in boston went on the air june 21, 1948 as wnac-tv. it is the second oldest television station in boston, and the third oldest in the new england states. the first owner was general tire, which later became rko general. the station showed cbs network programs when it first went on the air. the station also showed some programs from the abc network. however, when a new tv station in boston, channel 5, then known as whdh-tv but now known as wcvb-tv, started in 1957, channel 7 dropped all abc programs, which were then aired on channel 5. in 1961, channel 7 and channel 5 switched networks, and channel 7 became an abc station, and channel 5 became the cbs station for boston. in 1972, the two channels switched again, and channel 7 returned to being a cbs station, and channel 5 an abc station.