C-SPAN will have live coverage this morning starting at 10 of the Helsinki Commission on Security and Cooperation in Europe, featuring testimony by Anatoly Shcharansky . . .

Through Monday (12 days) in the local May ratings sweeps competition . . . Channel 9 news leads at 5 and 6 p.m. in the Nielsen count while Channel 4 leads at 11 p.m. . . .

At first glance, there doesn't seem to be any appreciable change in the Nielsen ratings patterns, despite the fact the firm agreed to "oversample" younger audiences during May, at the urging of Nine's competitors, who believe the previous sample, skewed to an older audience, favored Nine . . .

So far, from 5 to 6 p.m., Monday-Friday, Nine news has a 9.6 rating and a 25 percent audience share, while Four is next at 5.8/15, just ahead of Seven, at 5.6/15 . . .

From 6 to 6:30 p.m., Seven has a 6.7/16 . . . while from 6 to 7 p.m., Nine has an 11.4/26 and Four has a 6.9/16 . . .

At 11 p.m., Mondays through Sundays, Four leads with a 12.0/26, followed by Nine at 11.3/24 and Seven at 10.6/23 . . .

Channel 5 news at 10 p.m. has a 6.9/11. . .

Channel 7 has picked up the new syndicated late-night show "Night Life," hosted by David Brenner. Depending on what ABC has in mind for late night in the fall, it could air at midnight on weeknights after "Nightline," starting next fall . . .

The 30-minute program, already signed by 97 stations around the country, is distributed by King World Productions. Locally, Brenner enters the late-night competition that now includes the new one-hour "The Late Show Starring Joan Rivers," which Fox Broadcasting Co. will air on Channel 5 at 11 p.m., and Johnny Carson and "The Tonight Show" on Channel 4, which starts at 11:30 . . .

"NBC's 60th Anniversary Celebration," which ran for three hours Monday night but seemed 60 years long, averaged an 18.2 national Nielsen rating and a 29 percent share . . .

Phil Beuth, the ABC vice president in charge of "Good Morning America," yesterday denied a report -- repeated here -- in the New York Post that host David Hartman had been told to accept a 50 percent salary cut and a loss of editorial control of the morning program in negotiations for a new contract . . .

Beuth, who said he would have "no comment at all for the press concerning negotiations," went on to say he hasn't yet had any negotiations with Hartman, whose current contract, calling for a reported $2 million annually, is up in September . . .

"I've had a very cordial relationship with David," said Beuth. "Our only discussions have been concerned with what makes for a better show" . . .

Beuth hinted that the Post story came from a disgruntled former employe of "GMA" . . .

Tuesday night, both NBC News and ABC News aired footage of the Chernobyl nuclear accident site taken, they said, by a Yugoslav amateur video cameraman who was in Chernobyl the day after the April 25 explosion . . .

Yesterday, RAI, the Italian news agency, claimed the footage actually showed a Trieste cement factory . . .

ABC News got hold of the Trieste cement plant manager, who said it just looks like his cement plant but isn't . . .

Both ABC and NBC, who reportedly each paid $11,000 for the footage, are satisfied the film is legitimate. But they haven't forwarded the checks yet, either . . .

Also in the News

Here's the ABC fall primetime schedule, programming details of which we reported yesterday (N indicating new show, NT, new time period):

Monday: 8, MacGyver (NT); 9, Monday Night Football . . .

Tuesday: 8, Who's the Boss?; 8:30, Growing Pains; 9, Moonlighting; 10, Our Kind of Town (N) . . .

Wednesday: 8, Perfect Strangers (NT); 8:30, Head of the Class (N); 9, Dynasty; 10, Hotel . . .

Thursday: 8, Our World (N); 9, The Colbys; 10, 20/20 . . .

Friday: 8, Webster; 8:30, Mr. Belvedere; 9, The Last Electric Knight (N); 9:30, Sledge Hammer (N); 10, Starman (N) . . .

Saturday: 8, Life with Lucy (N); 8:30, The Ellen Burstyn Show (N); 9, Cold Steel & Neon (N); 10, Spenser: For Hire (NT) . . .

Sunday: 7, The Disney Sunday Movie; 9, ABC Sunday Night Movie . . .

Also next season, ABC will present what it's calling two "extraordinary" mini-series. The 12-hour "Amerika" depicts the U.S. in the mid-1990s, 10 years after the Soviet Union occupies us. "Out on a Limb" is a five-hour dramatization of Shirley MacLaine's autobiography -- extraterrestrials, reincarnations and all. Stars Shirley . . .

As we predicted yesterday, ABC Sports announced yesterday that Frank Gifford will remain as "host" on the "Monday Night Football" announcing team this fall, and also do the commentary, while Al Michaels takes over the Giffer's old play-by-play role in the streamlined format . . .

Gifford had been under serious consideration for a spot on "CBS Morning News" . . .

Winner of the 14th annual CBS/Tennis Invitational Monday night out at Arlington Y Tennis & Squash Club was the doubles team of Sen. Paul Laxalt (R-Nev.) and Billy Moses, star of CBS' "Falcon Crest" . . . which defeated the team of Rep. Norman Dicks (D-Wash.) and Peter Lund, president of CBS Sports . . .

In the semis, Laxalt and Moses defeated Rep. Byron L. Dorgan (D-N.D.) and Neal Pilson, executive vice president, CBS/Broadcast Group . . . while Dicks and Lund had defeated Susan Alvarado, vice president, congressional liaison, for the National Association of Broadcasters, and Rep. Robert Kastenmeier (D-Wis.) . . .

Sen. Laxalt's championship was his second at the CBS tournament, tying him with Vice President George Bush. He could retire the trophy with a third win. According to a CBS official, Mr. Bush has not participated in the tourney in recent years because "he felt he might tie up everything with all the security" . . .

23 Skiddoo

When Captain Airwaves reported yesterday that Bobby Ewing (ne' Patrick Duffy) was somehow coming back to "Dallas," Airwaves inadvertently wrote that the season-ending cliffhanger was scheduled for May 23 . . .

Everybody knows "Dallas," with Bobby Ewing, concludes this very Friday night (May 16)!fs,1 !fs,1 !

That's the way the tennis ball bounces, Airwaves! . . .

ABC rode "North and South: Book II" to a narrow victory over NBC last week, averaging a 15.6 Nielsen rating and a 26 percent audience share . . .

NBC scored a 15.4/26 while CBS sagged to a 12.4/21, which won't help the latter's May ratings sweeps chances at all . . .

In other notable developments for the week ending May 11, CBS' "Trapped in Silence" tied for 22nd, while NBC's "Dalton: Code of Vengeance II" tied for 24th with the second edition of NBC's "Fast Copy" . . .

ABC's Disney movie, "Young Again," was 37th, CBS' "The Blue Lightning" was 40th, while ABC's "Miss Hollywood 1986" and CBS' "West 57th" tied for 59th, just missing membership in this week's Final and in Every Single Instance Fatal Five . . .