to 41.6 million cable and satellite subscriber households nationwide. As WTBS, the station also served to help promote Turner's subsequent cable efforts, providing simulcasts of Cable News Network (CNN) and CNN2 (later Headline News and now HLN) upon their launches in June 1980 and January 1982, respectively, as well as offering weekend-long marathons promoting the 1992 launch of Cartoon Network. (CNN also produced the station's only conventional, long-form news effort as a superstation, the TBS Evening News, a prime time newscast that ran from July 1980 to July 1984.) Aside from Turner's use of WTBS to help launch his other cable ventures, Southern Satellite Systems also distributed the United Press International (UPI) teletext news service (from 1978 to 1981) and the Electra teletext service (from 1981 to 1993) to the vertical blanking interval (VBI) of the WTBS feed. WTBS remained the most widely distributed superstation for the rest of its existence under the format; by 1987, WTBS was available to 41.6 million cable and satellite subscriber households nationwide. A separate feed of WTBS intended for distribution to cable providers outside the Atlanta market, incorporating national advertising substituting commercials intended for its Atlanta viewing audience, was launched in 1981. (Since the original incarnation of the syndication exclusivity rules had been repealed by that time, program substitutions on the national feed were very limited.) WGN, WOR and other emerging superstations Turner's innovation signaled the development of basic cable programming in the United States and, within three years of WTCG achieving national status, was soon copied by other common carrier firms who decided to apply for satellite uplinks to distribute other independent stations as national superstations; however, while Turner had aggressively pursued national availability for WTCG, the other superstations that would soon emerge did not purposely seek such widespread reach and were either recalcitrant about having their signals imported without consent or ignored the issue directly and allowed their newfound expanded distribution to continue unfettered. On November 9, 1978, Chicago independent WGN-TV became America's second national superstation, when Tulsa, Oklahoma-based common carrier firm United Video Satellite Group, Inc. – one of four applicants, along with Southern Satellite Systems, Lansing, Michigan-based American Microwave & Communications and Milwaukee-based Midwestern Relay Company, that the FCC granted approval to operate satellite transponders to relay the signal following the institution of the FCC's distant signal "open entry" policy for carrier firms – uplinked its signal onto a Satcom-3