JERUSALEM, JULY 24 -- A plan to build a huge radio relay station for the U.S. government in Israel's Negev desert was revived today when an official planning commission reversed its earlier decision to postpone the project in order to study the facility's possible effect on migrating birds.

The switch by the National Council for Building and Planning prevented a potential embarrassment in relations between the U.S. government and that of Israel, which committed itself to the $290 million project three years ago and has already accepted U.S. funding for it.

The move outraged farmers and environmentalists who have been battling the project. They charged today that the planning officials had succumbed to political pressure, and vowed to take their case to Israel's Supreme Court.

The proposed station, with a field of antennas as high as 70-story buildings, is intended to improve broadcasting to the Soviet Union and Central Asia by the Voice of America, Radio Free Europe and Radio Liberty. The U.S. Board for International Broadcasting says $40 million in U.S. funds has already been invested in it, including $16 million advanced to the Israeli government.

The U.S. board welcomed today's reversal and said the radio facility would be "a voice for democracy and a spur to economic development in the {area}, and a tribute to U.S.-Israeli relations." It added: "The station will operate with the most stringent safety and environmental safeguards of any shortwave station in the world."

Opponents argue that the U.S. facility poses a danger to the millions of birds that migrate twice-yearly through the area -- from collisions with the antennas and disorientation from the energy fields.

In addition, Israel's air force has said electronic interference from the new facility might force it to move a nearby training site to land that is now a nature reserve.

Opponents also contend that the station, originally conceived in part to overcome Soviet jamming of shortwave broadcasts, is unneeded following the end of jamming and the changed political situation in the Soviet Union.

Last month, the Israeli Society for the Protection of Nature persuaded the planning commission to delay construction for two years to allow a study on the possible impact on bird migration. U.S. officials said such a delay would probably cause the project to be canceled.

Embarrassed Israeli officials quickly seized on the fact that the first decision was made when many government officials who dominate the planning commission's membership -- which also includes representatives of the Society for Protection of Nature and other citizen groups -- were absent. Today, with all its government officials present, the panel voted 19 to 6 to go ahead with the project, Israeli radio said.

Officials here said that if the commission's decision is confirmed by the government, which is considered almost certain, construction could begin by late this year and could be completed by early 1993.