 The Yuma Broadcasting Company, 45 percent owned by KTAR radio in Phoenix, was a stockholder, and KYUM also became a link in its Arizona Broadcasting Company (later Arizona Broadcasting System) chain.It operated with 250 watts during the day and 100 watts at night.KYUM carried NBC and ABC's dramas, comedies, news, sports, soap operas, game shows and big band broadcasts during the "Golden Age of Radio."