"Fantastic" was the reaction yesterday of Jim Keating, the WLLT-FM vice president and general manager, when he heard that CBS Inc. had agreed to buy WLTT and four other stations from Taft Broadcasting Co. Related story, Page D1.

Keating, who worked for CBS at its Philadelphia station, WCAU-AM/FM, for eight years, said, "Everyone here is excited about the news. It presents opportunities. They move people up through the ranks."

WLTT (94.7) has been a consistent revenue and ratings winner since it debuted with its "lite rock, less talk" format in March 1982.

In the recent Arbitron ratings, however, the station slipped from a 4.6 to a 3.5 share of the market. "We take a strong look after every rating book," said Keating. "We did our same analysis; we have an important franchise to protect. The deviation happens.

"This station has enjoyed a history of 10 solid books in a row. The probability for statistical deviation gets greater every book. But our audience is there."

This week, WLTT intensified its less-talk policy by dismissing one of the two people in its news department, Wendy Rieger, a reporter who had been on the staff for a year. The reduced number of newscasts are being handled by news director Robert Garcia. Gospel Changes

In the last few weeks, six employes, including air personalities Lou Hankins and Arnell Church, have abruptly left WYCB-AM (1340). "We had a layoff, and one person resigned," said general manager Howard Sanders, citing the drop in the station's revenues as well as the normal revolving-door life of a station as reasons. "We had more people than we had money."

Advertising rates are based on ratings, and in the winter 1985 Arbitrons WYCB had a 1.0, compared with 1.1 in the fall.

Two weeks ago, picketers protested outside the station in reaction to Church's dismissal. Also, the National Black Media Coalition is looking into reports of unfair management practices at WYCB. Honors

NBC Radio has won a Robert F. Kennedy Journalism Award for its series on street people, "Home Sweet Homeless," produced by Diana Quinn and reported by David Rush, and "The Invisible People," produced by Quinn and reported by C.D. Jaco . . . "Foreign Policy Processes & the Press," an American University course taught by John P. Wallach and aired over WAMU-FM (88.5) for 12 weeks last fall, has won a citation from the Overseas Press Club . . . CBS correspondent Richard Wagner won the Sigma Delta Chi Distinguished Service Award for journalistic excellence in radio reporting for his account of the death of Newsweek photographer John Hoagland in El Salvador . . . A few weeks back, Bill Mayhugh, the all-night steady at WMAL-AM (630), was named "Humanitarian of the Year" by Lions International. Beatles Bonanza

From 3 this afternoon to midnight Sunday, WASH-FM (97.1) will be playing the Beatles . . . At 6 tonight WMJR-FM (107.7) in Manassas will switch to a Beatles marathon until 7 Sunday night . . . WCLY-FM (95.5) is carrying "Ticket to Ride," the syndicated show of the renowned deejay Scott Muni, every Sunday night from 6 to 7. Public Accounting-

The three local public stations, greatly aided by National Public Radio's campaign, are all reporting impressive tallies in their recent drives. WETA-FM (90.9) raised $270,000 in eight days. WAMU raised $246,173 over seven days, including a pre-drive drive of $45,000. WPFW-FM (89.3) raised $89,335. NPR raised more than $6 million. An Anniversary

Starting Sunday, WDCU-FM (90.1) will be celebrating its third anniversary. From 8:30 to 10 p.m. Sunday it will broadcast live from Blues Alley with Les McCann. Prom and Party Project

WINX-AM (1600), the pioneer of Project Graduation, an anti-drinking and driving campaign, has signed up 19 schools to deliver its messages in this year's effort. Until the end of graduation and prom season, the station will be airing 30 messages in the teens' own words each day. Swing Results

Listeners of WWRC-AM (980) have voted for their swing-time favorites: male vocalist, Frank Sinatra; female vocalist, Peggy Lee; big band, Glenn Miller; group, Andrews Sisters; and song, "Stardust." Now that the poll is complete, Larry Walton will play one of the 2,000 versions of "Stardust" every morning at 8:20 indefinitely.