What it used to be called:
Starting in the 1970s, new TV channels started pouring into American homes via new technologies.
Broadcast TV i.e. the old-fashioned kind, transmitted over the airwaves became distinct from the cable and satellite options.
An early use:
"The kind of television most of us watch is broadcast TV. Television stations beam signals over the air, and anyone in the area with a TV set can pick up the signals." Kiplinger's Personal Finance, Sept. 1979