History of the National Football League on television
NBC was the first major television network to cover an NFL game, when on October 22, 1939, it broadcast a game between the Philadelphia Eagles and the Brooklyn Dodgers; the network was still only in its infancy, with only two affiliates, the modern day WRGB (now a CBS affiliate) in Schenectady and W2XBS in New York City. Portions of that game still survive via films, but the film is not footage from the telecast (recordings of television broadcasts did not begin until 1948). The use of a sideline camera, the sole camera used in the 1939 broadcast, would become the standard for all future NFL broadcasts until 2017; the angle is particularly suited for estimating yardage, compared to more mobile camera angles that began to appear in the 21st century.
NFL on CBS
On November 4, 1973, local San Francisco CBS affiliate KPIX (now an owned-and-operated station of the network) experimented with a "simulcast" in which the station kept switching back and forth between the network's broadcasts of a San Francisco 49ers game (against the Detroit Lions) and an Oakland Raiders game (against the New York Giants) that were being played at the same time, with frequent cuts to studio host Barry Tompkins. The station received many complaints from viewers, however, and the experiment was not repeated. This resulted in the NFL instituting new rules for markets that had two teams, which basically state that teams televised in two markets must play their games at different times in the day or week, or one of the teams must be on the road, or the teams' games must be on different networks. (For example, an NFL schedule for a given week in markets with two team franchises might look like this: Oakland at Kansas City, 1:00 p.m.; New York Giants at Philadelphia, 1:00 p.m.; San Diego at San Francisco, 4:15 p.m.; and New England at New York Jets, 8:00 p.m.)