With the selection only weeks away of a firm to get the lucrative, exclusive franchise to provide cable television in Montgomery County, competitors who have failed to get the top ranking have taken one last shot at both the leading applicant and the processs that selected it.

Yesterday was the deadline for the firms to submit comments to John Hansman, the county's cable project manager. Hansman and a citizen's advisory panel have recommended to County Executive Charles W. Gilchrist that a joint venture of Tribune Cable Communications of New Jersey and United Cable Television in Denver be awarded the franchise that could produce net revenues of $500 million to $750 million during the life of a l5-year contract.

Sheila Mahony, vice president of Cablevision, which finished seventh among the eight bidders, said "we have never been involved in a process that showed so little concern with public examination."

Unlike Montgomery, she said, the selection processes in Boston and Sacramento involved several hours of direct questioning in public meetings.

Montgomery Cable Communications, Inc/Times Mirror Cable Television, originally rated first by both Hansman and a private consultant, but ultimately made Hansman's second choice, pointed out that Tribune United was ranked fourth or below in such areas as operating plans and community programming.

Viacom Cablevision complained that scoring errors contributed to its third-place ranking.

First County Cable, a joint venture of a Canadian firm and Washington sports entrepreneur Abe Pollin, said that its proposal was shortchanged in the areas of service area, capability, experience and monthly rates and charges.

Tribune-United had no complaint about the process. It focused on its strong points: $1.5 billion in assets and revenues, 29 years of operating experience, and interactive services such as banking and shopping at home.