Each year radio stations compete fiercely to be the official promoter of summer concerts at Merriweather Post Pavilion, Sylvan Theater, Fort Dupont Park and other venues. That exclusivity gives them the privilege of flying their call-letter banners, enlisting their disc jockeys to emcee shows, doing remote broadcasts and giving away tickets and promotional items.

For the sixth year WRQX-FM (107.3) has landed the highly visible "official" rank with Merriweather, and is promoting more than 35 of the 50 concerts at the Columbia arena. "Our official tie-in is with Q107, but we really do promote with all the radio stations. We don't have just one presenter," says Robb Collis, Merriweather's assistant director of advertising and promotion.

However, a few stations are miffed at the relationship between Q107 and Merriweather and have talked informally about boycotting mention of concerts there. But the importance of the performers to their audiences has dampened any move to get even.

"The problem we have is that a lot of acts we play are at Merriweather. After a while you have to say, 'Our listeners don't know the politics, all they want to know is why their favorite station is not sponsoring the concerts,' " says B.J. Cohen, promotion director for WWDC-FM (101.1). "Many stations feel it would be better to break it up. So we try to work around it. We fought and fought and were able to work out an agreement on the Petty concert." WWDC is sponsoring Tom Petty at Merriweather June 9.

Some stations believe Q107 takes the best concerts whether or not it plays the music. "We take most of the mass appeal shows," says Marty Hall, Q107's director of advertising and promotion. "We might do a Willie Nelson, and it has been a while since we played Willie Nelson. But yet we would offer back John Williams and the Judds, a country act. And Iron Maiden is offered back to a hard rock station." The agreement is lucrative on both sides, he says. "We know when they need help they will come to us, and when we need to have front row seats, we can call them."

Some stations promote only those concerts that strictly fit their formats and avoid promotion of concert halls. "Our policy is to be very selective in choosing those concerts that we want to get involved with and the ones we perceive our audience will get involved with," says Alan Goodman, general manager of WAVA-FM (105.1) and a vice president of Doubleday Broadcasting Co. "We will not promote a concert hall per se. We think that hurts our credibility." WAVA is promoting the New Edition concert June 2 and the Commodores July 7 at King's Dominion. Both WAVA and WMAL-AM (630) are working with Wolf Trap Farm Park for the Performing Arts.

The summer line-up so far: Q107 kicks off its Merriweather season with a remote broadcast with Shadow Smith at 6 p.m. tomorrow. Inside, Gary Murphy will emcee the sold-out Madonna concert. WPFW-FM (89.3) is sponsoring the first Capital City Jazz Festival, headlined by Miles Davis, June 7 and 8 at the D.C. Convention Center. WKYS-FM (93.9) will be the official station of the Carter Barron Amphitheatre series from June 15 to Aug. 24. It starts with Angela Bofill. WKYS will also be doing a remote from the 1985 Potomac Riverfest at the Southwest Waterfront June 8 and 9. Later in the season it will sponsor the Capital City Community Festival at the D.C. Convention Center, July 19, 20 and 21. Starting June 21, WHUR-FM (96.3) is the official host of the Fort Dupont Park concerts. WWRC-AM (980) is cosponsoring the U.S. Park Service's Big Band Tea Dance Concert Series at the Sylvan Theater. The concerts start June 19 with Buddy Mautino and will continue every Wednesday through Aug. 28 except 4th of July eve. Tom Cunningham and the WRC 980 Orchestra will help kick off the Alexandria Red Cross Waterfront Festival at Founder's Park in Old Town Alexandria June 14. Piano Sounds

WETA-FM (90.9) is broadcasting the Seventh Van Cliburn International Piano Competition from Fort Worth, Tex., this weekend. The live show, anchored by comedian Steve Allen and Washington Post music critic emeritus Paul Hume, begins at 8 tonight and 6 p.m. Sunday. Video Sounds

WKYS will simulcast with Channel 20's special hour of "Video Soul," a presentation of Black Entertainment Television, Sunday at 7 p.m. The host of the show is the station's own program director, Donnie Simpson. Bulletin Board

WASH-FM (97.1) begins an all-British weekend at 3 p.m today . . . WLTT-FM (94.7) is counting down the 300 all-time "lite rock" faves, starting at 5 tonight . . . WETA will broadcast "The Herpes Media Blitz," a documentary about the myths and truths of the virus, at noon Wednesday.