Cable television has presented new challenges to the broadcast rating services. Developed originally in the 1940s (and for years known as CATV, Community Antenna Television), cable was strictly an extension of broadcast station coverage. It provided viewers satisfactory station reception in distant or difficult terrain situations by using strategically positioned antenna arrays and amplifiers and coaxial cable lines to carry the pictures to subscribers. The latter were thus able to receive some or additional TV stations with improved picture quality. By the 1960s, however, CATV had become cable. Growing penetration in some major cities such as San Diego and Buffalo, the expansion in number of channels offered to 36, 50 and beyond, and the emergence of Home Box Office and well- financed multiple service operators (MSOs) demonstrated that this was an important new communications medium that went well beyond its CATV beginnings. In 1976, the use of satellites to distribute cable-produced programming nationwide gave HBO, superstation VRTBS, and Spanish International Network (SIN) a major upward thrust. This quickly brought in new cable networks led by CBN and USA. Meanwhile, major MSOs were battling each other and local aspirants to capture franchises in every U.S. city with over 100,000 population. This resulted in a phenomenal growth, with 400,000 new subscribers per month being added as 1984 began and industry estimates placing cable penetration at 43 percent of U.S. television households by July 1984.
In order to understand some of the problems of measuring audiences of cable- oriented programs, one must appreciate the fundamental differences between cable and commercial broadcasting: