A chapter in radio history closed Sunday night at 11:30 when WWRC-AM (980) aired for the last time the NBC Radio News musical logo. At midnight, the station's 65-year affiliation with NBC ended and it became an ABC Direction network affiliate.

WRC was put on the air in August 1923 by Radio Corporation of America (RCA). Three years later RCA formed the first broadcasting network, National Broadcasting Co., making WRC one of NBC's original owned-and-operated stations. (The station was sold by NBC to Greater Media Inc. and an extra "W" was added to the call letters to denote the ownership change.)

In November, NBC Radio -- now based in Crystal City with sister-network Mutual Broadcasting System, both subsidiaries of Los Angeles contemporary music syndicator, Westwood One -- informed WWRC that it would move its news and Talknet affiliation to business-formatted WPGC-AM (1580) in 90 days. WPGC agreed to air the network's newscasts round-the-clock and carry all network commercials. WWRC aired the casts only overnight and accepted less financial compensation from NBC for commercials sold and broadcast by the network during newscasts. WPGC will also carry NBC's popular Talknet, featuring weeknight advice from Bruce Williams. However, few will be able to hear the programming. WPGC's 50,000-watt signal drops to 292 watts beamed westward at night from Morningside and is barely heard at the Washington Monument grounds.

To help solve the problem, WPGC general manager Ben Hill last week struck a one-year deal with WMET-AM (1150) owner/operator Sondra Linden to simulcast WPGC over the Montgomery County station. The arrangement calls for WMET to carry all programming from 5 p.m. to 5 a.m., Hill said. WMET can carry up to 100 percent of WPGC's programming at WMET's choosing. The station will have two hourly commercials to sell while WPGC and NBC sell the remaining eight to 10 per hour.

Both stations hope to attract audiences large enough to warrant network compensation. For now, WMET, which has experienced financial troubles in the past, will sell commercials during shows it produces and by selling blocks of air time for such ethnic programming as "Polish Panorama," an Afghani show, Indian shows and live soccer matches from El Salvador. The simulcasting began yesterday.

"This is an experiment. We are blazing new territory," said Hill, describing the deal as the beginning of a "turnkey network. If this works, then I'll look at others."

Hill said he has been approached by other AM operators and one FM station in the area about the possibility of creating a regional network.

Back at WWRC, operations manager Tyler Cox shortly after midnight yesterday described the switch-over as "a monumental engineering headache" because the station now uses four sources to get news and evening programming rather than one. Talknet's Bruce Williams has been replaced by ABC Talk's Sally Jessy Raphael, who several weeks ago called in to WWRC morning man Scott Carpenter to promote her arrival. She said returning to the station was something of a homecoming since she had gotten her first shot at network radio by trying out at WRC in the early '80s. "That was when the network was owned by NBC Radio, and, of course, that company doesn't even exist anymore," she said, taking a swipe at Westwood One. Cox said he was called by NBC Radio brass in Arlington, who requested a copy of Raphael's on-air remarks. WAMU's Talk Odyssey

After months of consideration, WAMU-FM (88.5) expects by the end of the week to name a replacement for Mike Cuthbert, who left the evening talk host seat in mid-October for a high-paying position in Boston. WAMU program director Steve Palmer said the list of possibilities has been narrowed to Cuthbert's regular replacement Matt Coates, Washington Post columnist Bob Levey, former USA Today on TV writer-producer Barbara Semedo, and Derek McGinty, co-host of WHUR-FM's (96.3) popular news hour, "The Daily Drum." These candidates apparently have met Palmer's advertised criteria: "experienced host who can handle broad range of topics, including controversial subjects, in a manner that is non-confrontational yet lively and entertaining."

The so-called "short list" follows hours of sometimes painful on-air tryouts of nearly a dozen hopefuls for the position, which could pay the host up to $45,000 annually. Said Palmer, "We are in no hurry. This is the kind of decision when you need to know you're right." Love That Crowd

WPGC-FM (95.5) morning host Robin Breedon announced her engagement on-air Valentine's Day to Bernard Holly, a Baltimore jeweler, and invited her audience to the June 15 wedding. (The reception is private.) She also has asked for suggestions on where to hold the event. The person who offers the wedding spot of Breedon's choosing will be part of her wedding party, said the gushing bride-to-be. Carter Barron amphitheater leads the list, but if Breedon's audience continues to grow as it has in several ratings surveys, RFK Stadium may be her only choice. Breedon intends to ask Jesse Jackson to perform the ceremony.