The Federal Communications Commission has issued a ruling that will make it more difficult for state and local authorities to restrict or prohibit installation of antennas for receiving television signals from satellites.

The FCC said its decision to preempt local zoning and other land-use regulations is legal under federal communications law. The agency adopted the ruling in a 3-to-1 vote Tuesday.

Delighted proponents of the federal preemption asserted that most of about 700 local zoning and other regulations that single out for regulation the back-yard and rooftop dishes will be invalidated under this order.

"This is absolutely a landmark decision," said Frederick W. Finn, an attorney representing a satellite television industry trade group -- known as Space -- that had pressed the agency to act. "It is the first time the FCC has formally recognized the benefits of home satellite technology, and taken a firm and concrete step to prevent restrictions that interfere with the delivery of those benefits."

In this area, Finn predicted, the ruling would affect "discriminatory satellite antenna" regulations in Baltimore and possibly in Prince George's County.

The agency said, however, that it would uphold local regulations if the community shows that they are based on a "a reasonable and clearly defined health, safety or aesthetic objective."

Local officials were unhappy with what many regarded as an unwarranted federal intrusion into local government.

"Our view is that local governments have not been restricting satellite antennas except in cases based on health, safety and aesthetics," said Leonard S. Simon, assistant executive director of the U.S. Conference of Mayors.

"Anytime that a federal regulatory agency arbitrarily limits local government powers that have been fairly and prudently exercised, we get deeply concerned," said Simon who added that he has not analyzed the ruling because it will not be released by the FCC until next week. "We don't think there was sufficient rationale for this ruling."

Albert Halprin, chief of the FCC's common carrier bureau, said that a decision by the U.S. Circuit Court of Appeals here last year concerning satellite master antenna television systems affirmed the agency's authority to preempt state regulation.

Under Tuesday's FCC rule, local satellite regulations also must not "impose unreasonable limitations on" or prevent the reception of broadcast signals from satellites.

The FCC said the decision "ensures that state and local regulations will not interfere unreasonably with the federal right to construct and use antennas to receive satellite-delivered signals."

The antennas are particularly popular in remote or mountainous areas where cable is not available and broadcast reception is limited. In a typical set-up, a dish-shaped antenna some six or eight feet in diameter is pointed at a satellite that picks up television transmissions and beams them back to earth.

Possessors of these antennas can receive various forms of pay-TV programs without paying, and they can pick up other transmissions such as advance feeds of network programs to their affiliates. Sales of the antennas, which can cost from $1,500 to $20,000, have been growing rapidly.

The FCC rule does not affect restrictive covenants, which are private provisions in property deeds that restrict an owner's right to make changes in his property.

The Prince George's County Council enacted controls in November on the construction and placement of television satellite dish antennas. Only dishes smaller than 10 feet in diameter are permitted to serve a single-dwelling unit unless the owner can prove that a larger one is needed.

The county rules also require a dish owner to obtain a building permit, ranging in cost from $20 for residential users to $75 for commercial users.

County Council member Sue V. Mills, who drafted the ordinance, said that she was not concerned the FCC decision would affect the county because its regulations were not unreasonably restrictive.

Jack Herrity, chairman of the Fairfax County Board of Supervisors, said he does not believe the ruling will affect Fairfax, because there is no county ordinance restricting satellite antennas, other than stipulating where the antennas can be placed in a yard.

Nate Gross in the D.C. Office of Planning does not believe the ruling would affect the District because the District zoning commission's grant of authority comes from Congress rather than the city government.