The Fairfax County School Board will consider a fact-finding panel's report today that concluded that the firing of a high school coach last year was too harsh a punishment for eavesdropping on an opposing football team, according to the coach's union.

The three-member panel recommended that former Langley High School coach Mike Weaver be offered a full coaching job next year, said Rick Willis, executive director of the Fairfax Education Association, which represents Weaver. Weaver has remained as a teacher and an assistant coach in the county system.

Fact-finding reports are not binding, but the FEA contends that the School Board is obligated by state law and its own policy to abide by the panel's recommendations because the board missed a 30-day deadline for acting on the report. Willis said he would recommend a lawsuit if the board does not agree.

The report was signed Oct. 7, the day the union says the clock began running. School system officials, however, said that the 30-day period began Nov. 13, when the report, transcript and an accompanying commentary by the staff were sent to School Board members at their homes. The unusual special Saturday meeting was called to beat that deadline.

School officials would not discuss the Weaver case, saying it is a confidential personnel matter.

Weaver was fired Oct. 8, 1986, after an investigation disclosed he eavesdropped on radio conversations of coaches from Madison High School during a game between the two teams the week before, school officials said at the time. Langley lost the game 14-7.

Sources said a member of the Langley coaching staff overheard Madison discussing strategy and that Weaver used the information during the game's second half. Neither team scored during that half.

Weaver, then in his fourth year at the McLean school, said at the time, "I made a bad mistake and I'm paying for it. I'm sorry it happened and I'm paying a price."

In firing Weaver as Langley's head coach, school officials cited a Virginia High School League rule that coaches are expected to maintain ethical standards, sources said.

Weaver filed a grievance with Langley Principal James E. Manning, who had removed him as head coach, contending that he had not violated the ethical standard and did not merit punishment, sources said. Weaver argued that the rule did not specifically mention eavesdropping on opposing teams.

Weaver lost in successive appeals to Manning and to two higher levels in the school system before the case was referred to the fact-finding panel. The panel said school officials had the right to discipline Weaver, but that the "discipline was out of proportion to the infraction," Willis said.

Weaver, 43, said yesterday he has a "mixed opinion" about that report, saying he had hoped to be completely vindicated. He now teaches at West Potomac High School and was an assistant coach at Herndon High School this year.

Willis said it is "hogwash" for school officials to contend the 30-day time period begins when School Board members receive the report in their homes.

But Edward W. Carr, assistant school superintendent for personnel, said a month is not too long to duplicate and mail a thick transcript. "It was processed in a reasonable time and I don't see that the grievant was harmed in any way as a consequence."