The first sentence of section
1291 of this title shall not apply to any joint agreement described in such section which permits the telecasting of all or a substantial part of any professional football game on any Friday after six o’clock postmeridian or on any Saturday during the period beginning on the second Friday in September and ending on the second Saturday in December in any year from any telecasting station located within seventy-five miles of the game site of any intercollegiate or interscholastic football contest scheduled to be played on such a date if—