There's a quiet little controversy going on in Washington that may significantly affect the kinds of programs Americans watch on public television stations and hear over public radio. At issue: How much money should Uncle Sam give public TV and radio in the next few years?
With Congress due to recess for the election campaign in about a month, no decision is likely until well into next year. But it should not be delayed longer than that, in order to permit the public TV network to make orderly plans for producing needed new programs.
The federal government now provides 20 percent of the funds the Public Broadcasting System spends. Most telling, federal funds provide half the money PBS uses to develop new programs.
Much of the federal funds are also used to obtain newer TV equipment - a task that public-TV boosters insist requires more money than is now appropriated. They note that many stations are using old and outdated equipment.
Some critics claim public television and public radio have elitist tendencies. Yet they aim to offer a balanced fare that is at least a notch higher than the average program on commercial networks.
They offer a low-budget window on the world of culture for many Americans, a televised parallel to the free trips through history and figuratively around the world offered by public libraries. For many Americans these are the only windows available.
The suspense about the size of future PBS funding is not unusual. But it is something that congressional backers of PBS had hoped to avoid this year.
During the summer, Congress had approved a measure setting out the amount of money it planned to give the stations, raising the sum from this year's $143.5 million to $238 million in fiscal 1987, $253 million in 1988, and $270 million in 1989. Backers pointed out that this would restore the funding to the level it would have been had not the Reagan administration trimmed it three years ago, and that by comparison each MX missile is projected to cost somewhat over $100 million.
President Reagan last week said he favored some increase for PBS, but that this one was excessive; he vetoed the measure. Congress probably should have anticipated such a response, but it did not.
Theoretically it is possible that the reconvening Congress may try to override the veto, and for the next few days backers of the bill will count noses to determine whether there is a realistic prospect of an override. Probably they will decide there isn't and will therefore put off action until next year.
PBS has two principal needs which increased funding could help to meet. One is for more new programs: The 1981 slash in funding has caused the network and its member stations to cut back on the number of ambitious new programs they are producing. As a result the number of reruns has increased, both on adult programming and children's, such as the popular ''Sesame Street.''
The second pressing demand is for more modern equipment and facilities, especially among smaller stations.
Congress and the administration still have time to get together and decide at what level to fund public television and radio; it would not be disastrous to wait until next year. Before 1985 is too many months along, decisions ought to be taken and a bill approved and signed into law. Even though it will only state an intent and not constitute the actually doling out of money, the authorization measure will give public TV and radio stations the lead time needed for future programming.