A consultant told the Alexandria City Council last night that the three companies competing to run a cable television system in the city should submit more information before the council awards a cable TV franchise.

A report by Stephen A. Sharp, vice president of the city's Consumer Affairs Commission, made no recommendation on which on the three proposals submitted by the firms should be approved. The commission is an advisory group appointed by the council.

The report praised the proposal by the Alexcom group as having an "imaginative financing program," although it appears to lack "adequate financial resources." That group, headed by several local businessmen, "does not appear to have any prior experience in cable television," Sharp wrote.

The Alexandria Cablevision Co. proposal to build a cable TV system over five years at a cost of $4 million "appears to be unrealistically low," the report says. The firm also lacks "clear commitments" for the money it says it needs, the report stated.

The Alexandria Telecommunications Corp. has an advantage because of its corporate relationship to the cable TV system now operating in Arlington, Sharp stated. That relationship means that the Alexandria company would not have to build a broadcasting tower in the city, as the other companies would have to do, Sharp wrote.

Sharp stressed that "the primary focus must be on financial qualifications."

The council as expected to award the franchise by May 1.