A proposal to open large blocks of free radio and television time to 1992 presidential candidates and voters will be presented Monday to the board of the Public Broadcasting System (PBS).

Called "The Voters' Channel," the plan envisages hours of new programming, including candidate profiles, analyses of ads, issue discussions and, possibly, candidate debates, scheduled with increasing frequency from the start of primaries until Election Day.

The John and Mary Markle Foundation of New York, which financed the feasibility study that will be presented to PBS directors in Dallas, has pledged $5 million toward the estimated $15 million to $20 million cost of the 1992 broadcasts.

Sharon Percy Rockefeller, president of WETA-TV here, described "The Voters' Channel" as "an electronic town meeting, a forum where voters can hear the issues they really care about discussed." She said enthusiasm for the project among public broadcasting officials is so great "there's no question in my mind but that this is going to be done."

If the project is created, it potentially could be the biggest change in presidential campaign communications since the advent of television and possibly begin to answer the criticism that TV has reduced campaigns to what has been called "a battle of 30-second ads and nine-second sound bites."

A key feature of the proposal is the offer of free time, in blocks ranging from 2 1/2 to 15 minutes, to presidential candidates and/or political parties.

Roger Ailes, television adviser to President Bush, reinforced in an interview what he told authors of the Markle feasibility study: "While I can't speak for the campaign, this is certainly something I would recommend to President Bush. I would think other candidates would use the opportunity this presents."

Ailes said that, depending on the dynamics of the campaign, he could envisage using the free time "to discuss an issue, to present a biography of the candidate, to highlight accomplishments in the record or do any one of 10 or 15 different things."

The feasibility study team, headed by Alvin H. Perlmutter, producer of many documentaries featuring Bill Moyers, acknowledged there was little agreement among the 120 political activists and journalists it interviewed on the best length, format or limitations, if any, for the free time. As a result, the study team postponed setting any conditions except that "the candidates themselves are seen and heard for a substantial portion of the time."

The report quoted Republican National Chairman Lee Atwater as saying that if free time were available on public radio and television channels, "certainly we'd use it. To fill five minutes, we'd have to put on substance, and we'd have to be very thoughtful."

Perlmutter proposed "bursts" of mini-series and specials coinciding with key events from the first primaries to the conventions, with a weekly, regularly scheduled, one-hour campaign program starting the first week in September, and daily half-hour programs in the final week before Election Day. The hope would be that they would be locked into the station schedules at a regular hour.

He described the mix as providing, through radio and television, "a well-rounded curriculum of programs, designed to provide both a political primer for those who need basic education and in-depth information for the politically sophisticated."

In addition to "a series of in-depth 'character and competence' profiles of all the aspiring presidential candidates," and an exploration of general-election candidate debates, Perlmutter suggested three additions to the public radio and television program mix:

"The Voice of the People, in which voters are given a means to articulate and express their feelings and concerns.

"Decoding the Message, in which all forms of political communications -- paid and free, parties and press -- are subjected to regular scrutiny and criticism.

"The State of the Nation, in which the present and future problems and options that confront the nation are carefully described and analyzed, irrespective of whether they are actually addressed by the candidates or the parties."

Edith Bjornson, project officer for the Markle Foundation, said she has begun soliciting support from other foundations for "The Voters' Channel" productions and is lining up corporate assistance for a major advertising and promotion effort, aimed at building the audience for these programs beyond regular public radio and television fans. Enlarging the public broadcasting audience will be a key factor in determining the impact of the project on the 1992 campaign.

"We feel very strongly that this is the right time to address the critically important problem of a turned-off, inadequately informed and disengaged electorate," she said.

"There is such a wide gap between the voters and the election process," Rockefeller added. "We want to fill that gap."