For months Emily R. McGonigal carried a portable radio around with her as she listened to the unfamiliar strains of country and western music, trying to memorize names of singers of whom she had never heard.

Monday her dedication paid off. McGonigal, a 31-year-old Oxon Hill mother of two, won $250,000 in the radio contest.

But her visions of crisp, fresh dollar bills have been drowned by a chorus of complaints that McGonigal unfairly had stuffed the contest entry box and that disc jockey Keith MacDonald inadvertently gave her a key answer over the air. There was even an anonymous complaint to the Federal Communications Commission, which has agreed to look into the matter.

Officials of the country music stations WPKX -- AM and WVKX -- FM, the Alexandria stations that sponsored the contest, said yesterday that they stand by McGonigal as winner of their "KX Country" event, designed to publicize the station's new call letters and music format.

McGonigal herself was equally adament. I prepared for this contest," she said yesterday, readily acknowledging that she and her husband sent the stations a total of 18,524 of entries. She had another 750 ready to drop in the mail when the station called, she said.

"I hardly knew anything at all about country and western music when I started," she said. "I made a 40-page list of records, a chart of all the hits, and a cross-index file of the performers. I carried that radio with me everywhere to learn the songs -- even to the bathroom."

What gave her a big edge in the contest, station officials acknowledged, was the number of times McGonigal and her husband, a telephone technician, entered. Connie Kiernan, promotion director for the stations, said the McGonigals accounted for 6,000 of the 40,000 entries that the station had received by Monday morning. Another batch of 5,000 McGonigal entries arrived after the contest was declared over, Kiernan said. m

An spokesman for the FCC, which is planning to look into the controversy, said the agency knows of no limit on the number of entries one person can submit to such a contest.

Much of the controversy, however, grew out of what disc jockey MacDonald told McGonigal when he called her and offered her the $250,000 if she could name the titles and the performers of the last three records the station had played.

Callers, who flooded the station with complaints, claimed that MacDonald blurted out the name of performer George Jones before McGonigal said it.

"She started to say 'George Jones' a shade before I repeated it," MacDonald said yesterday. A tape of the call has McGonigal and MacDonald speaking at the same time, although MacDonald's voice is louder. Station officials said that the volume of the announcer's microphone may have confused many listeners and led them to believe that he was leading her.

Because of the large number of entries she submitted, McGonigal was called twice last Thursday by the station. Once her line was busy, and once she made a wrong answer.