Although American Broadcasting Companies Inc. closed the $16-million deal for WMAL AM-FM last week, don't expect Channel 7 to change its call letters to WJLA until August.

The Washington Star Communications Inc. television station relinquished the familar WMAL to the radio stations as part of the ABC deal and has asked the Federal Communications Commission for an extension of the time to make the changeover.

Meanwhile, area stations have 30 days to comment on the proposed new call letters, which just happen to be the initials of WSC Inc.'s president, Joseph L. Allbritton.

WMAL-going-on-WJLA wants the extra time to come up with a whole new set of graphics and related promotion items.

MARKET MUTTERINGS: . . . Those weeknight tryouts for Sue Simmons, who came to Channel 4 from WBAL in Baltimore last fall, were no accident . . . she's reportedly due to emerge as co-anchor with Jackson Bain soon on the 6 o'clock news . . . which leaves Jim Vance where? . . . executives at WRC are planning other switches as both the early and late news shows continue to trail in the ratings . . . and there's talk that WTOP's "Nine in the Morning" is due for a facelift one of these a.m.s, too.

Channel 26, with a big boost from the appearance of Simon Williams (he's James Bellamy on "Upstairs, Downstairs") raised a near-record $29,600 the first night of its 15-day fund drive . . . and in case you were wondering, Channel 5 (WMAQ/NBC) in Chicago has seen its early evening news jump from third to a tie for first place in that very competitive market since Maury Povich joined the team . . . the station got a big audience boost when it stayed on the air live for two hours without a commercial during that elevated train disaster Feb. 4 . . .

DON'T ADJUST YOUR SET . . . Harry Reasoner was telling tablemates at last week's Radio and TV Correspondents Association dinner here that the networ's "throwing me out" and that he'd heard Channel 7's David Schoumacher is to replace him as co-anchor with Barbara Walters . . . he was, said a witness, only half-kidding . . . and the ABC hospitality suite that night was abuzz with rumors that Roone Arledge is about to be named "director of live programming" . . . that's sports AND news . . . at the network.

WAIT, THERE'S MORE . . . a White House source said yesterday that the 41-member Office of Telecommunications Policy is still "alive" but it will be at least four months until a decision is made about where OTP is to fit into the executive branch's re-organized structure, which is undergoing study by a task force these days . . .

Expect President Carter to pick his three choices for the Vacancies on the Corporation for Public Broadcasting board within the next two weeks . . . the White House quietly withdrew the names re-submitted at the last minute by President Ford in January.

And while we're in the neigborhood, don't expect any announcements on the two FCC vacancies (or the chairmanship) that open up July 1 for a while yet.

Forget reports that the Senate Commerce Subcommittee on Communications plans hearings on TV sex and violence . . . though the subject will undoubtedly be touched on in FCC oversight hearings later this spring . . . Friday, the reorganized committee added Democrats Wendell H. Ford (Ky.), Edward Zorinsky (Neb.) and Donald Reigle plus Republicans Robert Packwood (Ore.), Harrison Schmidt (N.M.) and John C. Danforth (Mo.) to the panel as Ernest F. Hollings (S.C.) took over as the new chairman, succeeding retired John O. Pastore.

NBC said yesterday it expects to announce an agreement with Carl Lindemann Jr. "within the next 24 hours" and sources in New York indicate the former vice president of NBC Sports will sign a sports program production contract with the network on an exclusive basis.

Lindemann resigned suddenly last Thursday, reportedly miffed over interference in his department from network president Robert T. Howard. Former had a big hand in obtaining the Olympic Games coverage for 1980 from the Soviet Union.

"We expect a continuing association with Carl," a spokesman said yesterday, adding that he won't be replaced.

The Olympic coverage will be overseen by Robert Mulholland, currently executive vice president of NBC News. An announcement on his assignment is expected any day now.