The Fairfax County Board of Supervisors yesterday set July 26 as the date for award of a cable television franchise, giving their staff an extra month to evaluate the charges and counter-charges filed by the two firms seeking the contract.

The postponement, from the previously scheduled session next Monday, means the board will have to resolve on the same day three of the most important issues it has faced this year. In addition to the cable issue, the board must approve replanning of the sparsely developed western quadrant of the county and a plan to promote intense development near the intersection of Route 50 and Interstate 66.

The latest delay also will give the cable TV companies and their more than 200 local shareholders more time to lobby, according to Annandale Supervisor Audrey Moore, who argued yesterday for an earlier decision.

"Emotions are running high and people are very concerned about it," Moore said. "I think we have about enough information to make a decision."

The scheduling debate came as Board Chairman John F. Herrity complained of a little-noticed passage in Fairfax Telecommunication Co.'s prospectus that indicates it may not perform as promised.

Both applicants, Fairfax Telecommunications and Media General Cable of Fairfax Co., are local affiliates of major national cable companies. Herrity for several weeks has urged their parent companies to guarantee in writing the performance of the local firms, so that the county will have assurances that financing is available to build the $100 million cable system.

Herrity said he was very concerned to find a disclaimer in Fairfax Telecommunications' stock circular saying that its national affiliate, Telecommunications, Inc. of Denver (TCI), is not required to pay for the Fairfax system. "TCI should be the cofranchisee applicant, the same as the opposition has agreed to," Herrity said. "This is a highly significant issue, very crucial."

The president of Telecommunications, John C. Malone, has assured the board in a public hearing and in a letter that his firm would fund the cable system.

A spokesman for Fairfax Telecommunications, John Reel, said yesterday the disclaimer is a "standard kind of caveat contained in a stock prospectus. Reel said he does not know whether the Colorado company will sign the franchise agreement -- as Herrity wants and as the Richmond-based Media General Co. has agreed to do -- but he said, "We'll certainly work to allay any concerns on the part of the board."