westinghouse entered television on june 9, 1948 with the sign-on of wbz-tv in boston; it is the only television station to have been built by the company. westinghouse's first station purchase was with wptz (now kyw-tv) in philadelphia, in 1953. kpix in san francisco was bought in 1954; wdtv (now kdka-tv) in pittsburgh was added in 1955; and waam (now wjz-tv) in baltimore was purchased in 1957. westinghouse's only other outright television station purchase was in charlotte, north carolina, where it purchased wret-tv from ted turner in early 1980, and changed its call letters to wpcq-tv. turner used the proceeds from the sale of the charlotte station to help him launch cnn.