Channel 26, faced with a $750,000 shortfall in predicted revenues this year, yesterday informed the staff that 13 positions were being eliminated.

Six employees of the current 218 will be let go by March 1, while another seven positions will be lost through attrition and retirement.

John Degenhard, acting chief financial officer for the station, said yesterday that expected revenues from local underwriters and WETA membership renewals -- which are applied to all local operations and station administration -- were running some $550,000 below projections made last June.

In addition, revenues from production contracts and grants were down at least $200,000, largely because of the loss of the "Smithsonian World" and "In Performance at the White House" series.

The White House last fall announced that "In Performance" would be produced this year by a Rochester, N.Y., public TV station. This past week Southwestern Bell informed WETA it was discontinuing $1.3 million in annual underwriting for "Smithsonian World" after the current fiscal year.

"We're making spending cuts to reflect the lower income," Degenhard said. "It's a midyear adjustment."

Degenhard said that a change in accounting policy mandated by the Corporation for Public Broadcasting also is reflected in the shortfall.

Added Degenhard: "We're going to be conservative in our revenue estimates until we know more about the state of the economy. It's still too early to project revenues for next year."

Employees to be terminated include a producer, assistant producer, a publicist and one staffer each from the development, national marketing and administrative offices.

Six other positions currently open at WETA -- in finance, community outreach and production offices -- will not be filled.

In a development unrelated to the staff cuts, WETA also announced yesterday that Mary Aladj, director of national communications at the station, will retire April 1. Aladj has been a key member of the WETA staff since 1978, after service with PBS.

However, the position will not be filled on her retirement.

Sharon Percy Rockefeller, president of WETA, said yesterday that "basically, due to the war and the local and national recession, we are not seeing the same sharp growth we've experienced the last several years.

"With six months to go we felt we should make the cuts; the sooner you deal with the problem the less onerous the cuts are going to be. We are very sorry for the six individuals and wish them well in the future."

Rockefeller insisted the news is not all bad at WETA. "We're currently looking at some 40 different projects in both television and radio. And we definitely are going to try to raise more money. We have a good future coming up."

All major public TV stations are in a period of belt-tightening right now. Last summer, WNET in New York cut 40 from its staff and stations in Philadelphia and Seattle have also reduced personnel.

The cuts come amid a very satisfactory year for WETA, which included airing such major projects as "The Civil War" series and "Making Sense of the Sixties."

Last July WETA budgeted a 5 percent increase in fiscal 1991, to a total of $50.5 million, but the projected income total did not develop.

Some $400,000 of the shortfall was in WETA membership renewals, according to Victoria Devlin, senior vice president, development and marketing. Instead of the projected 5 percent increase -- after six straight years of annual increases of 5 to 10 percent -- renewals have been flat this fiscal year so far, she said.

The annual spring on-air pledge campaign begins March 4 and runs through March 17. Devlin said the station has set a goal of $650,000 in pledges and will be seeking 6,000 new members to add to the current roll of 140,000 -- a total, Devlin points out, that represents "the highest member-to-viewer ratio in the entire public TV system: 27 percent." The March drive is the longest of three (the others are in August and December) national PBS fund-raising efforts each year. Despite the problems at WETA, Devlin promised that the March drive would not be extended this year.

In Other News Channel 4 has decided to renew "Jesse Jackson" for another season -- if Warner Bros. Domestic Television decides it's a go for 1991-92 ...

The one-hour program is produced at Four. Executives of Time Warner will decide at the end of this month whether to continue the series next fall ...

The 19th and 20th of 40 projected original programs (there will also be 12 repeats) will be taped this week. Some 138 stations are carrying the syndicated show at this time. After a very shaky beginning last fall, the program is now ranked in the top 60 among the nation's syndicated programs -- and is showing strength in the revenue-rich 18-to-49 adult demographics ...

"Jesse Jackson" airs at 8 a.m. Sundays on Four, where it finishes either first or second in its timeslot ...

While we're on the subject of syndicated shows, daily Variety says that the new King World Entertainment contract with Oprah Winfrey's Harpo Inc. for distribution of her "Oprah Winfrey Show" through 1994-95 comes on the heels of estimates that show will earn her company $50 million this year and up to $70 million by the 1992-93 season ...

Whatta guy! Channel 5 general manager Tom Herwitz looked out at the beautiful weather yesterday and at 2 p.m. told the office staff of about 200 -- which has been working extra hard since the war broke out -- to take the rest of the day off!! ...

It must be time to renegotiate contracts in Hollywood. Rumors are floating around that "L.A. Law" stars Jimmy Smits and Harry Hamlin, who have yet to sign contracts for next season, aren't returning to the series in the fall. Actress Susan Dey already has indicated her intent to leave, and executive producer David Kelley is taking off too, although he'll remain with the program as a consultant ...

The conclusion of "Son of the Morning Star" Monday night on ABC averaged a 12.8 national Nielsen rating and a 20 percent audience share. That gave the miniseries a two-night 12.3/19 average ...

During those same two hours, "The Marla Hanson Story" on NBC averaged a 15.1/24. On CBS the combination of "Murphy Brown" (18.6/28), "Designing Women" (18.5/20) and the one-hour Cher special (12.8/21) averaged a 15.7/28 during those same two hours ...

The bottom line (after all, there's a regional meeting of CBS affiliates in town): CBS won Monday night with a 15.3/24, followed by NBC at 14.4/22 and ABC at 12.6/20!! ...

(If visiting CBSers want to skip this next item we understand.) "ABC World News Tonight With Peter Jennings" led again last week with a 12.6/22, compared with a 10.6/19 for "NBC Nightly News With Tom Brokaw" and a 9.9/17 for "CBS Evening News With Dan Rather." That's three straight third-place finishes for Dan & Co. ...

TV RATINGZZZZ

Following are the top 20 network prime-time shows last week, ranked according to the percentage of the nation's 93.1 milllion TV households that watched, as measured by the A.C. Nielsen Co. A share represents the percentage of actual sets-in-use tuned to a particular program when it aired.

RATINGS....................................SHARE...NETWORK

1....23.1........Sarah, Plain and Tall.......35........CBS

2....21.8........Cheers......................33........NBC

3....20.4........American Music Awards.......31........ABC

4....19.3........60 Minutes..................32........CBS

5....18.3........A Different World...........28........NBC

6....17.7........The Golden Girls............30........NBC

7....17.6........America's Funniest Videos...26........ABC

8....17.5........Empty Nest..................30........NBC

9....17.4........Family Matters..............29........ABC

10...17.0........Full House..................29........ABC

11...16.9........The Cosby Show..............25........NBC

.....16.9........Murder, She Wrote...........25........CBS

13...16.2........Designing Women.............23........CBS

14...16.1........America's Funniest People...24........ABC

15...15.7........Unsolved Mysteries..........24........NBC

16...15.6........The Simpsons................24........FOX

17...15.4........Murphy Brown................22........CBS

18...15.1........Davis Rules.................22........ABC

19...15.0........Wings.......................24........NBC

20...14.9........Who's the Boss..............23........ABC

ABC was the most watched network again last week, finishing first for the fifth time this season. ABC hasn't won that many weeks in a season since 1983-84 ...

ABC won despite the absence of its top show, "Roseanne," which was preempted by the State of the Union address Tuesday ...

Meanwhile, five-year champion NBC finished third for the third straight week. For the week ending Feb. 3, ABC averaged a 12.7/20, compared with a 12.4/20 for CBS, a 12.1/20 for NBC and a 7.1/11 for FOX ...

As NBC continues to struggle, the season-to-date race narrows. The Peacock Network still leads with a 12.8 rating but it's only half a point ahead of third-place CBS at 12.3, while ABC hovers near at 12.6 ...

Viewers were plainly looking for relief from the war news last week, viz., the triumph of the nostalgic "Sarah, Plain and Tall" on CBS ...

The regular timeslot premiere of "Davis Rules" on ABC was good for 18th place ...

NBC's Sunday movie, "In Broad Daylight" finished in a tie for 29th, while Part I of "Son of the Morning Star" was only 42nd ...

The George Burns 95th-birthday special on CBS was 50th, while the movie awards on CBS tied for 56th ...

NBC's "Dark Shadows" was 65th, NBC's "Main Event" wrestling show was good for 74th while the premiere of NBC's "Sunday Best" proved to be Sunday's worst, finishing 81st ...

ABC's "Twin Peaks" could do no better than 83rd, making the cut for this week's Final and in the Long Run Fatal Five Plus One ...

The FAITLRFFPO this week also included FOX's "America's Most Wanted," in 84th, followed by NBC's "Real Life With Jane Pauley" and ABC's "Under Cover," which tied for 85th, and two FOX shows, "Comic Strip Live" and "Against the Law," toes up in 88th and last place ...