Channel 26 says that tomorrow and Wednesday it will air live coverage of the Senate Judiciary Committee's hearings on the nomination of Associate Justice William Rehnquist to be chief justice of the U.S. Supreme Court . . .

The hearings are expected to run from 10 a.m. until 4 p.m. each day. WETA commentator Paul Duke will anchor the coverage . . .

"A tremendous amount of pressure" from key CBS affiliates was a major factor in Friday's decision to put "CBS Morning News" on the shelf by the end of the year and replace it in January with a two-hour program that will be produced by a new unit to be formed within the CBS Broadcast Group . . .

Years of unsatisfactorily low ratings for the two-hour time period -- not only reducing ad revenues for local stations in that time slot but adversely affecting the size of morning audiences and revenue potential in the morning time slots following the network show -- finally prompted a revolt, according to CBS executives . . .

"There has been agitation for over a year," one executive who declined to be identified told us this weekend . . .

"They still want a news division involvement in the morning but they also want some of the 'sizzle' of entertainment-oriented programming" . . .

Last week, top news division executives agreed that "the best of several alternatives was to remove the two hours from CBS News, retain a format that was informational in nature but produced outside the division," one source said. That decision was ratified by CBS Broadcast Group President Gene F. Jankowski on Friday and the announcement was made . . .

Most of the 50 employes of "Morning News" reportedly will be retained in one capacity or another following the transfer, but some job losses are expected by January . . .

One source told us that for more than a year, affiliates had "been calling us up" to complain. Powerful broadcast groups such as Group W, which has CBS affiliates in San Francisco and Pittsburgh, "let us know what they think" . . .

At the May affiliates' meeting, when network management expected to hear complaints about CBS' loss of the primetime leadership to NBC, the complaints were "almost all" about "Morning News," according to our sources . . .

"That's when that joke surfaced that the network shouldn't sacrifice 'Simon & Simon' against 'The Cosby Show' next fall and put 'Morning News' up against Bill, instead," said one executive who was there . . .

The alternatives for hurting affiliates were made plain to CBS management . . .

With the arrival of Paramount and Fox Broadcasting as additional potential program suppliers, the opportunities for many of the CBS affiliates to sign up for "bartered" programming (for which a station pays nothing and shares in the advertising time available) made threats of mass defections more plausible . . .

CBS News President Van Gordon Sauter, in his announcement to the news division on Friday, promised that the 6 a.m. show, "CBS Early Morning News," will continue and that the news division "will be a significant contributor to the new 7-to-9-a.m. broadcast," come January . . .

Sauter, as a CBS Broadcast Group executive vice president, will be in charge of the new broadcast group unit producing the two-hour program starting next year . . .

That almost guarantees considerable news division presence on the revamped program, which is expected to retain numerous features like sports, weather and consumer information . . .

It is possible that CBS will go to units in other divisions, such as Woman's Day magazine or CBS Records, for help in devising the new format . . .

"The whole idea is more flexibility," one executive told us. "Keeping it out of the entertainment division and removed from News could give us flexibility in talent and location. We could even go to a live audience. It would be impossible, say, to have Alan Alda as a host, if the program remained in News and it would give the wrong tone if he came aboard with Entertainment running things from out on the Coast. But as an independent unit, ideas like that might work" . . .

Philip A. Jones, chairman of CBS' affiliates advisory board, called Friday's decision "a good compromise, a good move" . . .

Jones, vice president and general manager of KCTV in Kansas City, said it will enable the broadcast unit to make decisions for "program reasons and not journalistic reasons." He told the Associated Press that the show would have more flexibility away from the news room, although news and information would remain a part of the program mix . . .

"I think it will be more sensitive to the likes and dislikes of the morning audience," Jones added . . .

The CBS Broadcast Group is expected to elaborate on its Friday announcement for the affiliates sometime later this week . . .

In the most recent weekly ratings, for the week ending July 18, NBC's "Today" averaged a 4.3 Nielsen rating (each rating point represents 859,000 TV homes) and a 21 percent share of the viewing audience, compared with a 4.1/20 for ABC's "Good Morning America" and a 3.0/15 for "CBS Morning News" . . .

Although the spread was uncharacteristically small between "Today" and "Good Morning America," the CBS count was about average. More devastating was the CBS performance last Wednesday, when "GMA" averaged a 9.0/31 for its coverage of the royal wedding in Nielsen's 12 major markets, compared with an 8.8/30 for "Today," while CBS languished with a 4.2 rating and only 14 percent of the vastly increased morning audience . . .

"Morning News" consultant Susan Winston is scheduled to meet with Sauter today. She was brought in last April to conceive a new format, with new anchors, for "Morning News." But many of her ideas were knocked down by management as too costly or perhaps recherche' for a news division program.

It's just possible that Winston, who has talked publicly of quitting after so many rejections, may reconsider now that many of her ideas would play for a program removed directly from the news division. She has an October "window" in her two-tier contract with CBS that would permit her to quit . . .

The morning time period has been a headache for CBS for 32 years. For the past 23 years there's been a "CBS Morning News." After years of producing a one-hour news show that contended with the two-hour programs on ABC and NBC, CBS went to two hours in 1981, removing "Captain Kangaroo" from the schedule. The Captain's audience did not mesh with morning audiences in the 7-to-9-a.m. period . . .

Although several interesting combinations were tried after 1981, including Bill Kurtis and Diane Sawyer, nothing worked over the past five years. The most recent combination, of Forrest Sawyer and Maria Shriver, gained critical approval but audiences still stayed away in droves . . . Also in the News

Alarmed public TV officials report that 30 public TV stations around the country have been dropped from cable systems since the Federal Communications Commission's "must-carry" rules were found to be unconstitutional a year ago . . .

Channel 26 here, for instance, has been dropped from a Baltimore-area system that reaches 100,000 homes . . .

The FCC will rule again on "must-carry" in August . . .

For the second straight week, CBS daytime programming has clobbered ABC's lineup of soaps and game shows . . .

For the week ending July 18, CBS averaged a 6.7 Nielsen rating and a 23 percent audience share, compared with a 5.6/19 for ABC and a 5.4/19 for NBC, which is moving into a position to challenge ABC . . .

The winning margin was the biggest for CBS since the week ending Dec. 23, 1984 . . .

The top five shows for the week: CBS' "The Price Is Right II"; CBS' "The Young and the Restless"; the Daytime Emmys award show on NBC; ABC's "General Hospital"; and NBC's "Days of Our Lives" . . .

Appearing on the "Sally Jessy Raphael" show tomorrow (Channel 9, 10:30 a.m.) will be Larry Brown, president of 70001 Training & Employment Institute, a Washington-based nonprofit organization which runs 60 programs in 23 states for high school dropouts . . .