Just as a police dispatcher in his windowless office can tell when it starts to rain by the surge of traffic accident calls, Max Friedersdorf can measure each Monday's passing hours by the ringing of his White House office telephones.

Monday mornings, few of the 535 members of Congress over whom Friedersdorf watches as head of congressional relations for the White House are in Washington, but, as they hit the airport returning from their weekends at home, Friedersdorf's telephones blink more insistently, and he begins to place more calls.

After the Carter administration hiatus, Friedersdorf, who is white-haired, courteous bordering on courtly, and could easily be cast as a member of Congress, is back as chief of congressional relations for the White House, the same job he held under President Ford.

From the day after his election triumph, President Reagan spoke of wanting to hit the ground running in Washington. Perhaps his fastest start was in the wooing of Congress.

A week before Friedersdorf signed aboard, Reagan made his first visit to Capitol Hill as president-elect, and came away with rave reviews, Friedersdorf had about seven weeks' head start, and had his staff in place two weeks before Reagan was inaugurated.

It is difficult to find a member of Congress with anything negative to say about the White House's approach to Capitol Hill. Some may not like Reagan's programs, but they have been somewhat thrown off balance, if not disarmed, by the Reagan presentation.

Even many Democrats praise the Friedersdorf operation. "They're smooth, they're on the ball," said Sen. Earnest F. Hollings (D-S.C.), ranking minority member of the Senate Budget Committee, which will have first crack at Reagan's spending cut plan starting with hearings this week.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) is another example. President Carter, many of whose goals O'Neill shared, started their relationship off with a series of small slights.

O'Neill couldn't get extra tickets he wanted to the Carter inaugural. At his first White House breakfast, hearty-eater O'Neill got only a hard roll made even harder to swallow because O'Neill, like other congressional guests, was billed for the fare.

The result was a headline-making Carter-O-'Neil rift that was patched up only later.

Reagan began his relationship with an embrace. The speaker has been to the White House for a private dinner for four with Mrs. O'Neill and the Reagans. He was invited to the Oval Office for the president's 70th birthday party, and he has been consulted many other times.

Reagan and his top aides long ago decided that the best strategy often is to hold potential enemies close, so close that they can't move their arms, one official commented.

O'Neill met Carter's top aide, Hamilton Jordan, only three times in four years, an O'Neill assistant said, while he feels comfortable with Reagan's top advisers, and the only time he needed something from the White House, he got it.

Faced with the possibility of widespread Democratic defections on the vote to rise the federal debt limit, O'Neill asked Friedersdorf for a letter from the president to each Democratic member asking for support.

O'Neill was impressed that Friedersdorf promised the letters without checking with Reagan, and doubly impressed that they arrived the next day. "They produced," an O'Neill aide said.

Reagan and his top three White House aides, Edwin Meese III, James A. Baker III and Michael Deaver, are all sensitive to the need for good relations with Congress, which makes Friedersdorf's job easier.

"It's like they've worked in congressional relations before," Friedersdorf said of the three senior Reagan aides. Deaver had the idea of holding a 70th birthday party for Reagan in the Oval Office and inviting congressional leaders, he added.

It doesn't hurt Reagan or Friedersdorf that they succeed a president whose relations with Capitol Hill began wretchedly and improved only moderately.

Friedersdorf, 51, defines his strategy by two numbers: 51 votes in the Senate and 218 in the House.

If he gets those totals, even though he admits "We'd like a few more," he's a success.

"I don't think politics ever goes out of style," Friedersdorf said. "I don't have a bad connotation of that word. Politics means to facilitate."

To facilitate enactment of Reagan's programs, Friedersdorf and his 12 assistants aim to provide all the service they can to the members of Congress.

Ken Duberstein, Friedersdorf's top aide for the House, said members of his team have paid at least one visit to all 435 House offices. If the member of Congress has been out, they have talked to the staff.

Their emphasis, in their first meetings, Duberstein said, is on letting the legislators know the congressional relations office wants to help.

They are also following up on Reagan's promise that he will not take Congress by surprise and is looking for the reciprocal assurance that the White House won't be blindsided.

At least for now, almost nothing is too small if it helps build a solid foundation for good relations in the future.

"We try to be attentative to the little things, on the theory that if you take care of them, the big things can take care of themselves," said Friedersdorf's deputy for the Senate, Powell Moore, who makes it a point, when asked, to arrange birthday greetings from the president to constituents of senators.

Several members of Congress cited the preparation of Reagan's economic package and of Carter's first energy program as illustrations of the contrast between the Reagan and Carter approaches.

Meese and Baker worked closely with key members of Congress to explain the package and prepare its way before it was made public. The Carter program was handed down without such careful advance preparation.

"I've never been to so many meetings, but that's the way to do it," Hollings said.

Care and feeding of Congress is not limited to elected members. Steve Bell, staff director of the Senate Budget Committee, noted that the chief staffers of the Senate's four principal money committees -- Appropriations, Finance, Budget and Banking -- were invited to the White House a couple of weeks ago for a first-hand look at what was available to them from the liaison office.

When congressional staff members have had problems with executive agencies, Friedersdorf's people have stepped in to straighten them out, Bell said.

Friedersdorf said he intends to pursue good relations with every member of Congress: "I'm not writing off anybody at all." Even from Democratics who may not back Reagan with their votes, the White House hopes for a willingness to share information.

"A member of Congress needs information. Sharing it promptly often helps," Duberstein said.

The big tests lie ahead on whether the magic numbers 51 and 218 can be won for Reagan's program. The toughest part of the job so far, Friedersdorf said, has been helping the political clearances for White House personnel. For each happy job candidate and happy sponsor there are a lot of unhappy ones, he said.

Despite rough moments over personnel, Friedersdorf has no complaint about the way the president's program is being handled. "There seems to be a good attitude up there," he said.

Republican members of Congress are predictably more enthusiastic about their relations than Democrats. A few liberal Democrats said they had not seen any White House representatives, while most Republicans said they had been given quick and complete cooperation.

Sen. Jesse A. Helms (R-N.C.), who's probably had more problems with the administration over nominations than any other Republican, gives "an A+" to the Friedersdorf operation.

"He can't do everything for you, but he gives it the old college try," Helms said. "Call it stroking or whatever, it's absolutely essential."