Virginia Republicans hosted a boisterous, banner-waving show-of-strength rally for Ronald Reagan here tonight and promised a flurry of campaign activity on his behalf during the remaining 30 days of his presidential drive.

Despite a chilly rain, Reagan's appearance in Norfolk filled half of this city's 12,000-seat Scope Arena with fans of the former Californian governor. cThe largely Tidewater-area crowd cheered the GOP nominee, unfurled pro-Reagan and anti-Carter signs and joined in when he was serenaded with such patriotic songs as, "I'm Just A Flag-Waving American."

In addition to putting out a friendly welcome mat for Reagan, state Republican leaders used the event -- which was advertised on radio and television -- as a kind of celebration of party strength and unity.

Although recent state polls indicate the contest for Virginia's 12 electoral votes may be a lot closer than the walk-away Reagan victory predicted by many, President Carter is seen as particularly vulnerable in this, the only southern state he lost in 1976.

"My friends, we're talking about bread and butter on the family table," Gov. John N. Dalton cautioned in a shouting attack on Carter's economic policies. The governor and other Republican leaders who spoke at the rally said the president's reelection would mean "four more years of disaster" in both economic and foreign policy matters."

The governor, former Gov. Mills E. Godwin, Sen. John W. Warner, state Attorney General J. Marshall Coleman and several Virginia congressmen sat on the stage with Reagan to spotlight the state party's strong endorsement of his election.

Coleman, who is expected to win his party's nomination for governor next year, praised the state's voters for being "skeptical" of Carter four years ago. He urged Republicans not to take Victory for granted, saying "Jimmy Carter is doing everything he can for the Republican Party, but he can't do it all himself."

As the Virginia officials had done, Reagan assailed Carter's domestic and foreign policy actions and accused the president of gross mishandling of the economy. "A recession is when your neighbor loses his job, a depression is when you lose yours, and recovery will be when Jimmy Carter loses his," Reagan said.

Carter's defense policies and the Tidewater region's outcry over his decision to send two aircraft carriers to Philadelphia for overhaul have done little to boost his popularity in a state already known for its conservatism.

GOP leaders here also claim they are able to work enthusiastically for their candidates while some Democratic leaders are only lukewarm in their support of Carter.

"I had one Democratic official tell me that he was tired of making up excuses for Carter," reported state Sen. A. Joseph Canada Jr., a Virginia Beach Republican.

Canada pointed out that both Godwin, who favored John Connally's candidacy, and Virginia's Rep. William Whitehurst, who was George Bush's state campaign chairman, are actively pushing Reagan's election now.

Whitehurst is distributing "Reagan/-Whitehurst" literature in his own congressional campaign, and Godwin made a rare public appearance to introduce Reagan to the Scope audience.

"That's a real contrast to when Mrs. Carter visited here last week and many Democrats in leadership positions were conspicuous by their absence," said Canada. "I don't think they want to be too closely tied to the president."

Rosalynn Carter spent four hours in Virginia last Thursday. She attracted a large, black crowd at a voter registration rally in Norfolk but drew only half the number expected at a later Virginia Beach reception.

State Democratic Party officials have gamely predicted that Carter, though trailing now, will carry the state on Nov. 4. But Lt. Gov. Charles S. Robb, who squired Mrs. Carter around during her visit, says a Virginia victory for the president will be "an uphill struggle."

Carter is expected to make his first and only campaign appearance in the state this month, in western Virginia, to try to shore up his support.

Reagan, by contrast, has had high visibility in the state. He has turned the Wexford estate in Middleburg into a temporary home during the campaign, and he dropped in on his new neighbor, Warner, when the latter hosted a Republican fund-raiser at his farm last month. Reagan's running mate, Bush, will be coming to Roanoke on Oct. 9.

All this, Republicans say, is designed to keep the GOP presidential nominee's lead intact in the Old Dominion. But it's no secret that party leaders see this national election as a great way to build momentum for their crucial statewide contests just a year away.

"We don't want to lose," says the GOP's state executive director, Jeff Gregson. "We've got a streak going, and we don't want to lose it. We see it as carrying us over to next year."