WAVA-FM (105.1) and WRQX-FM (107.3) both will broadcast the entire Live Aid concert from Philadelphia and London tomorrow.

The stations will be simulcasting the promising-to-be-phenomenal day, which benefits Ethiopian famine relief projects, from 6 a.m. to midnight. Both are taking the same feed from ABC Radio Networks, the exclusive radio broadcaster for what is believed to be the largest live music event ever planned. Q-107 plans color reports from both concerts, including on-site observations from advertising and promotion director Marty Wall, who will be at Wembley Stadium in London. Piano Notes

Starting tonight, the University of Maryland International Piano Festival & Competition, celebrating its 15th year, can be heard on WGMS (103.5 FM/570 AM). For the festival opener, the Archduke Trio will perform from Tawes Recital Hall at 8:30 p.m. Then the semifinalist performances will be broadcast at 6:05 p.m. from Monday through Friday. The competition will move to the Kennedy Center July 20, when the finalists will perform with the National Symphony Orchestra at 8:30 p.m. Paul Teare, WGMS program director, and John Chester, assistant program director, will produce and host the shows. Special Reports

Today and for the next four Fridays, the Mutual Housing Association, a private, nonprofit group, will host a series on how moderate- and low-income people can purchase housing, on WPFW-FM (89.3) at 12:30 p.m. . . . "All Things Considered" cohost Susan Stamberg is heading a National Public Radio news delegation of eight to the current United Nations women's conference in Nairobi. Along with political correspondent Linda Wertheimer, she will start daily reports Monday. Prime Guests

After hearing a spoof "Robert K. Dornan Charm School" ad on WMAL-AM (630) a couple of weeks back, the colorful California congressman volunteered to spend a half hour on the Joe Palka Show tomorrow at 1:05 p.m. Playing off Dornan's reputation for name-calling and tie-grabbing, Palka intoned, "Having trouble landing that first date? Do it the Dornan way," followed by another voice that said gruffly, "You don't wanna go out," and then gave a raspberry. Judy Boufford, the congressman's office manager, said his response would be "all in fun. He has a marvelous sense of humor" . . . Larry King takes his talk to Baltimore's Harborplace tonight. Listeners of WTOP-AM (1500) at 12:05 a.m. can hear Mayor William Donald Schaefer and Orioles manager Earl Weaver. WAMU Shifts

Citing declining audiences on Saturday and Sunday nights, program director Craig Oliver of WAMU-FM (88.5) announced some shifts in the weekend lineup. On Saturday: "All Things Considered" will start a half-hour earlier, at 6 p.m.; "Hot Jazz Saturday Night" and "The Duke Ellington Hour" with Robert Bamberger have been combined into one show from 7 to 11 p.m.; followed by "Vintage Jazz at the Vineyard." On Sunday: "ATC" at 6 p.m.; "The Big Broadcast," 7 p.m. for four hours; and "Marian McPartland's Piano Jazz" at 11 p.m. (a different McPartland show from the 6 a.m. broadcast). Another addition to the schedule is "The Dick Spottswood Show," a survey of vernacular music from bluegrass to Cajun to calypso, Saturdays at 3 p.m. Music Specials

This weekend WXTR (104.1 FM/1560 AM) will be playing all top songs that followed "Rock Around the Clock's" debut at No. 1 in July 1955 through 1980 . . . WGMS is broadcasting "AT&T Presents Carnegie Hall Tonight" on Saturdays at 6 p.m. until September. On tomorrow's program is the Minnesota Orchestra playing Argento and Respighi . . . WDJY-FM (100.3) has a new feature, "Washington's Music Magazine," which spotlights War on Sunday from 11 a.m. to noon . . . Bob Duchesne, a member of the WMZQ (98.7 FM/1390 AM) team, will be hosting the national show "American Country Countdown" tomorrow on AM from 10 a.m. to 1 p.m.; repeated Sunday on FM from 8 to 11 p.m. . . . At 8 p.m. Wednesday WETA-FM (90.9) airs a concert of Paul Badura-Skoda taped earlier this year at the Church of Our Lady of Perpetual Help in Southeast. The producer is the Washington-based Arts Connection. Bulletin Board

WPKX (105.9 FM/730 AM) is cosponsoring a concert at Wildworld in Largo with the Nitty Gritty Dirt Band, tomorrow at 6 and 8 p.m. . . . Gary Alan of WASH-FM (97.1) will help Swensen's (Van Ness and Wisconsin Ave. NW) construct a banana split boat for the D.C. Special Olympics Sunday from 1 to 4 p.m. . . . Trumbull and Core of WMAL hope to raise funds to send senior citizens to a summer camp, next Wednesday from 3 to 7 p.m. Last year they raised $14,000.