Since the dawn of television, almost six decades ago, every TV station in America has had the capacity to beam out just one program at a time — Gunsmoke or The Huntley-Brinkley Report or Survivor or 60 Minutes. That was then; welcome to now: the Digital Era of broadcasting. The so-called analog, one-channel version of television will soon be as archaic as a 1950 Studebaker. Since the passage in 1996 of a new Telecommunications Act, all of the country’s television stations are allowed to reach their viewers on as many as six channels — simultaneously! Benefits for the public have been slow in coming, but suddenly “multicasting” — that’s the hot new word — is on the lips of everybody in TV land.