Congressional leaders' hopes for swift, smooth passage of a resolution of condemnation against the Soviet Union dimmed yesterday as a group of conservative Republican senators proposed to add a call for tougher sanctions than President Reagan has invoked.

A half dozen or more senators, led by Jesse Helms (R-N.C.), served notice that they will attempt to add a recommendation for stiff sanctions to a condemnation resolution that Majority Leader Howard H. Baker Jr. (R-Tenn.) and Minority Leader Robert C. Byrd (D-W.Va.) have scheduled for Senate action today.

The Baker-Byrd resolution strongly condemns the Soviets for shooting down a Korean airliner with 269 aboard on Sept. 1 but, in line with Reagan's policy, speaks only generally of international sanctions.

"The president will be missing a golden opportunity if he doesn't nail the Soviets' hide to the wall . . . ," Helms told reporters in urging the administration to go "beyond the threshold of rhetoric and do something substantive."

He added, "I want to make sure the Senate of the United States goes beyond talk."

The Helms proposal calls on Reagan to recall the U.S. ambassador to Moscow for consultations, to reduce the number of Soviet diplomats to the number of U.S. diplomats stationed in the Soviet Union and to conduct a "comprehensive reappraisal" of all U.S.-Soviet relations, including arms control negotiations and trade.

It seeks to link arms control with Soviet actions on the airline disaster, Poland, Afghanistan and other points of East-West tension.

It also would have Poland declared in default on farm loans, tighten controls over export of high-technology and other American products to the Soviet Union and bar importation of goods produced by forced labor.

An earlier proposal, introduced late Monday by Helms and Sen. Steve Symms (R-Idaho), went even further in several respects, including urging a temporary suspension of arms control negotiations until the Soviets agree not to shoot down U.S. military reconnaissance aircraft.

Some conservatives had indicated that they couldn't accept the most drastic of these provisions, such as suspension of arms control talks. A discussion of the proposal at a closed-door Senate Republican luncheon was reportedly heated, as even some of the most conservative senators argued against divisive debate that could send mixed signals to Moscow.

At least one Democrat also joined the campaign for more specific retaliation. Sen. Walter D. Huddleston (D-Ky.), a member of the Senate Intelligence Committee, proposed an amendment to the condemnation resolution that would put Congress on record as favoring a reduction in the number of Soviet government employes in the United States by at least 100.

But the conservative Republicans opened the door for what may be a full-scale debate over the administration's response to the Soviets' action by objecting Monday to Baker's request for a brief debate without opportunity for amendments.

Also yesterday, the Japanese government released a transcript of the air traffic control radio transmissions between its controllers and the Korean flight after it was "handed off" by U.S. controllers in Anchorage.

The transcript shows normal communications until Flight 007's last transmission, a call sign broadcast at the time U.S. officials say the plane was shot down. "Signal was noisy and weak," the transcription says. Several attempts to reestablish radio contact were made by Japanese controllers, but to no avail.