KSTU will be cutting back on the number of prime time movies it will be showing this season by expanding to three the number of nights the station will be showing first-run series programming.

And no, that doesn't mean they're going to pick up Fox's Saturday night line-up - whatever that may be this week. While Ch. 13 will continue to carry Fox's Sunday night series (with the exception of "Duet," which is being replaced at 9 p.m. by Fox's "The Reporters" pseudo-news magazine), the two new nights of series programming - Friday and Saturday - will be comprised of original syndicated series.On Fridays KSTU will air "Star Trek: The Next Generation" at 7 p.m., followed by the new series version of H.G. Wells' "War of the Worlds" at 8, "Barney Miller" at 9 and "Taxi" at 9:30.

The Saturday line-up will have an even heavier science fiction tilt toward it, beginning at 5 p.m. with the sitcom "Small Wonder," "The New Munsters" at 5:30, the original "Star Trek" at 6, a new episode of "War of the Worlds" at 7, "Friday the 13th: The Series" at 8, the new "Nightmare on Elm Street: Freddy's Dreams" at 9, "Monsters" (a collection of ghoulies from "Tales of the Dark Side") at 10 and CBS's recent "The Twilight Zone" series at 10:30.

The Friday night showing of "War of the Worlds" will be a repeat of the previous Saturday night's installment. And "Star Trek: The Next Generation" will be repeated Sundays at 5 p.m.

"War of the Worlds" is an updated version of the Wells classic and the science-fiction classic motion picture about the invasion of earth by unfriendly aliens. "Nightmare on Elm Street" is a horror anthology, hosted by the infamous Freddy Kruger (played by actor Robert Englund) . . . and occasionally featuring Freddy. And "The New Munsters" picks up where the 1960s series left off - only with the characters played by new actors (including John Schuck and Lee Meriweather) and living in the 1980s after having been accidentally frozen by Grampa Munster.

"We believe in these shows," said KSTU programmer Deb Anderson in explaining the moves. "They are prime time-caliber programs, so we felt we needed to play them in prime time."

Which is not to say KSTU believes any less in the prime time movies they have been offering for years. In fact, Anderson said the station has spent nearly a million dollars during the past few months on what she calls "the cream of the movie crop," with new titles like "Predator," "Peggy Sue Got Married," "Iron Eagle," "The Fly" and "Aliens" set to air on Ch. 13 this season. But the new prime time movie time on KSTU has been moved up to 7 p.m., followed by "Barney Miller" and "Taxi" reruns at 9 and 9:30 p.m., respectively.

Also new on KSTU this season will be "Inside Sports . . . And All That Jazz" (Sundays at 10:30 p.m.), a sports talk show hosted by Carl Arky and produced by the Utah Jazz.

"We're excited about the changes," Anderson said. "We feel like it marks the beginning of a new stage in our development."

You'll have to decide for yourself if in this case "newer" sounds like "better."

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***MORE GOOD NEWS/BAD NEWS for NBC in last week's Nielsen ratings. The Olympics are performing well enough to keep the network solidly in its accustomed number one setting. But they still aren't doing as well as the network expected - or as well as they promised advertisers they would do. Looks like NBC is headed for Make-Good City, and will lose some of that tidy profit they anticipated in making things up to Olympic advertisers.

Oh, and in case you're curious, ABC edged out CBS for the network ratings silver.

For the record, the top 10 programs for the week were: 1. Summer Olympics-Thursday (NBC); 2. Summer Olympics-Saturday (NBC); 3. Summer Olympics-Friday (NBC); 4. Summer Olympics-Sunday (NBC); 5. Summer Olympics-Wednesday (NBC); 6. Summer Olympics-Tuesday (NBC); 7. Summer Olympics-Monday (NBC); 8. Monday Night Movie: A Stranger Waits (CBS); 9. Head of the Class (ABC); and 10. Growing Pains (ABC).

The second 10 consisted of: 11. Summer Olympics-Early Sunday (NBC) and Growing Pains (ABC); 13. Growing Pains (ABC); 14. 60 Minutes (CBS); 15. Head of the Class (ABC); 16. Murder, She Wrote (CBS); 17. Monday Night Football (ABC); 18. NFL Football (CBS) and Newhart (CBS); and 20. The Cavanaughs (CBS).

The week's big losers (not counting Fox and Ben Johnson) were: 48. Garry Shandling: Alone in Las Vegas (ABC); 49. Bodywatching (CBS); 50. West 57th (CBS); 51. First Impressions (CBS); and 52. Frank's Place (CBS).