Commercial television is going to use its own airwaves to promote public television. In an interview conducted in the New York headquarters of Public Broadcasting Service, its new president, Bruce Christensen, revealed that ''The Stars Salute Public Television,'' a two-hour syndicated fund-raiser for PBS, will air on independent commercial stations throughout America at the end of January or early February 1985. The director will be award-winning Don Mischer, who directed the recent ''Motown 25th Anniversary Show'' on NBC and the ''Kennedy Center Honors'' on CBS.
Mr. Christensen, who came to PBS from his post as president of the National Association of Public Television Stations, had earlier served as general manager of public television stations in Utah. He was especially grateful at the time of the interview that it appeared almost certain that $70 million in supplemental appropriations for the Corporation for Public Broadcasting, which, in part, funds PBS, would be approved by Congress. Capitol Hill had already appropriated $130 million per year for the 1984-1986 period.
Mr. Christensen says he does not believe that the Reagan administration's attitude toward PBS indicates an attempt to control its content.
''The President genuinely believes there should be no federal money in public broadcasting, that the people who look at it ought to pay for it. It's an ideological point of view, having more to do with economics than with program content.''
Finding ways to make PBS on-air pledge drives more acceptable to the public is one of Mr. Christensen's major problems at the moment. ''We hear rising criticism of fund-raising drives, but when you look at the amount of time spent doing that, it's really not more than 1 or 2 percent of our program schedule. When you compare that to the commercial networks, they're spending 20 to 30 percent of their time in advertising.
''But even so, if it is offensive to people, we have to see if we can do better with direct mail. Can we be more sophisticated with on-air pledging, can we spread the pledging out over an entire schedule rather than concentrate it in one period? In some areas stations are trying pledge-free periods with the understanding that there will be no on-air fund raising if the money is sent in by a fixed time. It worked in Boston. So, we have a lot of experimenting to do.''
Public television gets about 20 percent of its money from the federal government at the moment and Mr. Christensen would like it to go back to the 25 percent it used to get - but no more. ''We don't want any single source of funding to be so great that it dominates other funding mechanisms.''
How does he feel about advertising on PBS as a source of revenue?
''If there is a way that we can be sure that advertising does not become a dominant force financially, that it doesn't drive out other revenue sources like underwriting, and if you can be sure that advertising does not begin to control your programming through a kind of ratings game, maybe advertising could be a source of revenue.''
Mr. Christensen indicates that there have been suggestions that ads be run only on weekends, that they be clustered before and after shows, that they might be shown for half an hour a day, back to back.
Mr. Christensen does admit, however, that there are many station managers who are absolutely opposed to any kind of advertising ''for philosophic reasons that relate to the nature of the institution.''
According to Mr. Christensen, other sources of revenue - a tax on the sale of TV sets, a ''spectrum'' fee to TV stations for use of the airwaves, income-tax check-offs - ''don't stand much of a chance politically.''
However, he is encouraged by the positive effects of the recently formed Corporations in Support of Public Television (CSPT), an organization of underwriters and potential funders who help each other learn more about PBS and make decisions to fund public television. Only recently, United States Fidelity & Guaranty wrote a letter saying the organization helped them make a deci-
sion to fund the show ''International Edition.'' And CSPT member IBM recently made a $1 million grant to WQED for a science/geology series, ''Planet Earth.''
What are Bruce Christensen's top priorities in the job? ''First has to be a way to raise funds in a better way. Then, we must replace some of our aging technical equipment. And, of course, programming. We must pay more attention to our educational responsibilities, preparing the right kinds of material for classroom use based on such top-notch programs as ''Civilization and the Jews,'' ''Constitution: A Delicate Balance,'' and ''Congress: We the People.''
''But, perhaps most important, we need to do a better job for children. That has become largely a public TV responsibility over the past few years. We accept the challenge. Kids programming will remain a major concern for PBS, and with additional funding you will see us doing wonderful programs for youngsters.''
Mr. Christensen feels that cable TV has fallen into a familiar mass-audience approach to programming.''It's the same pattern as the commercial networks - they only want programming which will bring them the highest rate of return for their investment.
''PBS is concerned with quality and public service and it is clear that cable is not going to offer us the kind of competition we once expected.''