President Reagan yesterday gave Senate Republicans the go-ahead to seek a bipartisan budget alternative but stopped far short of giving any ground in advance or locking himself into a future compromise.

After a series of meetings on Capitol Hill between the president and most of the 53 Senate Republicans, Majority Leader Howard H. Baker Jr. (R-Tenn.) said he is convinced that Reagan will compromise on the budget and that "nothing is off-limits" in reaching a compromise.

But participants said Reagan offered no substantive concessions in any area, including his defense buildup and tax cut programs, from which congressional leaders hope to get money to help offset what they see as intolerable deficits in the next few years.

The president was "conciliatory in tone and firm in position," White House communications director David R. Gergen said.

"I do not think he's closed the door to anything, but I would be careful to point out he has not agreed to anything," Baker said.

"The concrete has not yet cracked around his feet," Sen. Dan Quayle (R-Ind.) said.

Moreover, Reagan threw a potential stumbling block in the way of Democratic cooperation on budget revisions.

While asserting that Democrats would have to offer more than just token support if a bipartisan budget effort is to succeed, the president continued to blame Democrats for the country's economic problems.

He accused them of having pursued "planned deficits and deliberate inflation as a supposed means of preserving prosperity" and questioned whether their policies have changed.

But Reagan paid a courtesy call on Minority Leader Robert C. Byrd (D-W. Va.) who said later that he offered the president several proposals, including deferring the 1983 tax cut, examining defense spending and moderating monetary policy. Byrd said Reagan indicated some willingness to consider defense cutbacks.

In an apparent effort to dispel mounting congressional panic over deficits as a driving force behind high interest rates, Reagan held out hope for a big drop in interest rates during the next few months. He was quoted by a Senate leadership source as saying Federal Reserve Board Chairman Paul A. Volcker had told him recently that Volcker expects interest rates to fall by three or four percentage points by summer.

But Reagan's conciliatory tone, rather than any matter of substance, was cited by members in expressing hope--heavily qualified in some cases--that a climate for compromise may now exist. Reagan had belittled congressional budget rewriting efforts during a campaign swing last week, prompting complaints from Senate leaders. There was no such talk from the president yesterday.

"He expressed a willingness to work with us and asked us to submit alternatives," Budget Committee Chairman Pete V. Domenici (R-N.M.) said. "I think it is fair to say there was some flexibility on the part of everyone at the meeting," Finance Committee Chairman Robert J. Dole (R-Kan.) said.

Domenici, Dole, Baker and other leaders are meeting nightly on budget revisions that they hope Reagan can embrace, with Baker pushing for a package as early as next week. They are understood to be considering tax increases and some cutbacks in military spending, along with deeper cuts in benefit entitlement programs than Reagan has proposed, in order to produce lower deficits.

Also under consideration is freezing nondefense appropriations at 1982 levels.

Sources said yesterday that the group has virtually ruled out any change in the 10 per cent tax cut proposed for 1982 and 1983. They also said Reagan appears to be adamantly against any changes in Social Security, including elimination or modification of cost-of-living increases as some Republicans have proposed, until a study commission reports later this year. House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), who rarely agrees with Reagan, did so yesterday on the issue of cutting Social Security. While cost-of-living increases for federal retirees might be cut back, O'Neill said he is "kind of adamant" on protecting Social Security from any cuts.

On the critical questions of tax increases and defense cuts, participants in the 80 minutes of meetings said Reagan had few specifics to offer. Reagan met first with Baker and Republican Conference Chairman John G. Tower (R-Tex.), then with committee chairmen and finally had an hour-long lunch with most of the Senate Republicans.

Although Reagan was not asked directly at the luncheon about military spending, Tower said the president indicated that he wants his entire program, including taxes and defense, "unsullied to the extent possible."

Gergen was equally ambiguous, saying Reagan is open to any proposal that "meets his basic standards and comes with a broad range of bipartisan support." When reporters noted that Reagan's own budget lacks bipartisan support, Gergen responded, "Well, that's right."

Reagan was reported to have responded favorably to suggestions from Baker and others that he appear on television more often--perhaps, as Baker has suggested, for five minutes each week--to generate support for his overall program.

Reagan also talked about a major television address, and White House aides are discussing one devoted largely to defense.

"It's time to get our sabers and charge," Reagan was quoted as saying at one point in the meeting with committee chairmen. It was not clear at whom he would charge, but a leadership aide said the senators, despite Reagan's broadsides at Congress last week, are not worried that it might be them.