The Senate yesterday authorized an 11.7 percent pay raise effective Oct. 1 for the 2 million men and women in the armed services.

That is nearly double the 6.2 percent raise President Carter proposed in his budget for both military and civilian employes. If the House goes along as expected, it would be the first time in recent years that military employes got more than civilian, and the civilian unions are sure to resist.

But Pentagon advocates say the military needs the extra money, in part to stem losses of skilled people that are threatening readiness and calling into question the move seven years ago to an all-volunteer army from the draft. i

The pay provision was tacked onto a budget-breaking $5.19 billion weapons authorization bill that is $5 billion above what Carter requested. Among many other things, it would authorize the Pentagon to start work on the MX missile and direct defense officials to have a new bomber flying by the mid-1980s.

The House has passed similary legislation; the procurement bills are the latest in a series in which Congress has moved to lift defense spending in the years ahead.

The pay provisions was quickly protested by the American Federation of Government Employes, which represents 700,000 workers.

"There's no real reason for it," said AFGE spokesman Gary Dinunno, "except to cut back on our wages." He said his group welcomes more money for the military but that the government's civilian employes also have lost ground in recent years.

The government's civilian employes are supposed to be paid comparably to their counterparts in the private sector. Military raises have bee based on civilian.

The president in his budget asked Congress to change the current civilian comparability formula in part to take into account higher government fringe benefits and retirement pay. That would make a 6.2 percent pay raise fair, he reasoned.

Congress has shown little interest in pursuing a new pay formula for civilians. But they have shown intense interest in raising military pay in response to pleas from the joint chiefs of staff. Higher pay would help stem the exodus of skilled people from the armed services, the chiefs said.

The Senate voted to separate civilian and military pay for fiscal 1981 only. It directed the president to submit to Congress by next April a new method for computing military raises.

Pentagon leaders have argued that the hardships and risks of military life justify higher raises for soldiers than for government civilians.

Although the House did not authorize the same 11.7 percent in its weapons bill, it is almost certain to go along with it during the upcoming House-Senate conference. And it is unlikely Carter would veto a military pay raise in this election year.

The pay raise, educational benefits and other actions designed to improve service life will cost a total of $948 million more than Carter had requested outside of research and procurement.

The president had requested $46.9 billion in his procurement bill for ships, aircraft and missiles. The Senate authorized $51.9 billion, a $5 billion increase. The House was even more generous, adding on $6.2 billion to the president's request.

Senate votes on specific weapons evidence an impatience with the Pentagon's penchant for putting off production of new weapons year after year.

In discussing the approval of $91 million to start on a new bomber and instructions to the Pentagon to submit a comparison study of the three leading candidates by Feb. 15, Senate Democratic Whip Alan Cranston (D-Calif.) said:

"These actions forcefully demonstrate that Congress wants a follow-on bomber and will wait no longer for the executive branch to request that new bomber."

Despite the warning from the Pentagon's research director that the Soviets would have a new defense installed soon that could knock the plane down, the Senate Armed Services Committee had recommended spending $91 million to stretch 155 F111 aircraft already flying into longrange bombers. The program would end up costing $7.2 billion, according to conservative estimates.

But when the stretched F111 proposal came up for a vote, Sen. John Culver (D-Iowa) shot away at it, telling his colleagues: "To throw money at a penetrating bomber that won't penetrate is the height of irresponsibility."

Sen. John Glenn (D-Ohio) and Cranston cosponsored an amendment to allow the Pentagon to use the $91 million the committee had recommended for the stretched F111 alone to study various bomber options.

Glenn said that perhaps one plane could be developed to fulfill three different missions: conventional bombing, launching cruise missiles and penetrating Soviet airspace.

"What we are saying is to settle down on the F111 is premature without considering the others," said Glenn.

In response to protests from Sen. Jon Tower (R-Tex.), whose state would receive many of the F111 contracts because the plane's builder, General Dynamics, has its plant in Fort Worth, Cranston said:

"To force the development of a new bomber must be our common goal . . . The Congress has become impatient and has taken the matter into its own hands."

The amendment, which passed by voice vote, directs the Pentagon to find a bomber which would be ready for deployment "in the mid-1980s."

The chosen plane could be the stretched F111, variant of the B1 bomber Carter canceled in 1977, a "multi-role" bomber, an advanced one "or an appropriate mix of such aircraft."

The House has approved a fixed-wing version of the B1 bomber and said it should be built to carry cruise missiles.

The Senate took these other actions on major weapons funded in the procurement bill:

MX missile. Rejected, 80 to 9, an amendment by Glenn to put the MX land missile on trucks which would motor around the United States rather than deploy them in the valleys of Nevada and utah.

Battleship New Jersey. Rejected 50 to 41, an amendment by Sen. Dale Bumpers (D-ark.) to delete $294 million earmarked for bringing the New Jersey out of mothballs.

The Navy would end up with "a Rube Goldberg ship" under the various plans for arming the battleship, warned Sen. John Chafee (R-R.I.), a former secretary of the Navy.