1970-00-00 (unknown year) WTCG (the future WTBS) Atlanta, Georgia, began microwaving its signal to cable systems in nearby cities.
1970-01-00 Turner Communications Group changes the call letters from WJRJ to WTCG, which stood for Turner Communcations Group, but some said it stood for Watch This Channel Grow. The sale was completed on April 6.
1970-10-04 National Educational Television (NET) had its final day of broadcasting.
1970-10-05 the Public Broadcasting Service (PBS) network signed on as a successor to National Educational Television (NET).
1971-00-00 Instructional TV (ITV) began on a few cable systems in San Diego.
1971-09-08 the Manhattan Cable regional sports network begins to be referred to as the Madison Square Garden Sports Network (later as The MSG Network).
1972-00-00 Channel 100 (PAY), run by Optical Systems Corp. and cable company franchised, was launched on Mission Cable in San Diego.
1972-00-00 Appalachian Community Service Network was sent through microwave.
1972-08-16 Channel 46 was launched in Los Angeles.
1972-11-08 HBO (PAY), originating from Wikes-Barre, debut on microwave. Some of the games held at Madison Square Garden were featured in the channel's early years.
1972-11-20 Channel 50 was launched in Orange County.
In 1972, Pay programming begins. TelePrompTer delivers the first pay sports programming on its Long Island system. Home Box Office (HBO) delivers its first pay TV programs by microwave (a movie and a hockey game) to 365 subscribers in Wilkes-Barre, Pennsylvania.
In 1972, HBO provides, via microwave, the first original cable television production of The Pennsylvania Polka Festival from the Agriculture Arena in Allentown to customers of John Walson's Service Electric, a cable system in Wilkes-Barre, Pennsylvania.
Source: The Cable Center website: Cable History Timeline: http://www.cablecenter.org/resources/exhibits/cable-history-timeline.html