The Reagan administration is furtively using the complicated budget reconciliation process to bestow on commercial broadcasters a host of fabulous regulatory prizes -- enough to make it, for them if not for the viewing and listening public, Christmas in July.

Yesterday a House-Senate conference committee reached a compromise on measures that lengthen the license periods of radio and TV stations and, public interest groups charge, make it easier for even errant broadcasters to hold onto their valuable licenses and fend off challenges from others.

Andrew Schwartzman, executive director of the Media Access Project here, called the bill "truly awful" and said, "The supposed compromise goes far beyond what the broadcasters ever hoped they could have gotten just one or two years ago. It will seriously impair the kind of progress we have made in broadcast coverage in the last 15 years; it brings the efforts of citizens' groups to a crashing halt."

Basically the compromise, expected to reach the Seante floor tomorrow and to pass along with all the other measures tucked into the reconciliation bill, extends the terms of radio-station licenses from the present three years to seven, lengthens TV-station licenses from three years to five, establishes a complicated new lottery procedure for awarding new licenses -- one that may undo progress made in encouraging minority ownership -- and give the Federal Communications Commission the power to throw out challenges to existing licenses at the commission's discretion, if not whim.

Schwartzman, whose group was one of 31 organizations and individuals opposing the measures, said the compromise was "fife with little goodies for broadcasters." Still, it has fewer goodies than the broadcasters wanted and the prime mover behind the luxurious bequests, Sen. Robert Packwood (R-Ore.), was anxious to give them.

If Packwood had gotten his way, the bill would have made it virtually impossible to challenge broadcast licenses for renewal until the FCC had revoked a station's license first -- something the commission has very rarely done. Packwood would have granted radio broadcasters their licenses in virtual perpetuity, with no time limit, and eliminated an FCC requirement that radio stations keep detailed logs of what they put on the air. If that provision had passed, there would be little if any chance of enforcing the FCC's Fairness Doctrine, which requires stations to give air time to all sides of controversial public issues.

For what they are about to receive, however, the broadcasters are still truly grateful. "We're happy," said Shaun Sheehan, spokesman for the National Association of Broadcasters. "We're still not 100 per cent there, but this is a tremendous step along the way."

Did the NAB lobby heavily for the Packwood proposals? "Of course," Sheehan said. "We felt obligated to use what resources we had." According to Shwartzman, "Even from the broadcast lobby, I've never seen a blitz like what's been going on the past couple of weeks."

Packwood's office referred all inquiries yesterday to spokesmen for the Commerce Committee, of which he is chairman and where the legislation originated.

What infuriates Schwartzman, Ralph Nader, and other invoked in the fight against the Packwood proposals is the fact they were hidden away in the budget reconciliation bill, even though most are not budget-related. One budget item, however, that also made it out of the weekend's work will delight public broadcasters. Funding of $390 million for the Corporation for Public Broadcasting over the next three years -- slightly less than the House proposal of $140 million a year but considerably more than the Senate alternative of around $100 million a year -- was authorized.

And the public broadcasting forces prevailed with a formula that insures substantial funding for national programming, contrary to the wishes of OMB Director David Stockman, who had pushed for a return to Nixonian days of "localism" in public TV and radio -- thereby debilitating the idea of national public networks that can produce, among other things, programs on national political and social issues.

Schwartzman conceded the broadcasting measures that emerged from the conference committee amounted to a "substantial modification" of the original and gruesome Packwood plan, but said the extension of license periods "severely, seriously, quite profoundly impairs the enforcement of the Fairness Doctrine" because complaints about a station's Fairness Doctrine performance are traditionally and most easily voiced at license renewalk time.

The hastiness in pushing through these major revisions in communications law strikes critics of the proposal as highly suspicious, particularly since Congress is circumventing its usual procedures on regulatory policy, including open public hearings. Packwood was, according to Hill sources, adamant about pushing the broadcast items through, even at the expense of delaying the entire reconciliation process.

Sources confirmed that Sen. Howard Baker (R-Tenn.), the majority leader, urged Packwood to relent on the broadcasting issues last week but that Packwood's pack would not budge. On Friday, House speaker Thomas P. O'Neill (D-Mass.) wrote Baker complaining about the lack of progress on the reconciliation effort, specifically on telecommunications and other issues under the jurisdiction of Packwood's Commerce Committee.

"A major stumbling block appears to be in the Senate committee's insistence on including a provision for the deregulation of radio and television, which has no appreciable budget impact and has not yet been acted on, or even considered, by the House," O'Neill wrote.

Bob Witeck, a spokesman for the Commerce committee, said Packwood stood his ground for as long as possible because "when you're negotiating something as difficult as this bill, you don't give up anything without getting something in return. From a strategic standpoint, we made it clear we had areas in which we would not change."

But Schwartzman said of Packwood's intransigence, "In part it may have been a sincere ignorance about the impact of what he was doing. But I can also speculate that it is related to Sen. Packwood's interest in seeking higher office in 1984."

Last week Ralph Nader, chairman of the National Citizens Committee for Broadcasting, charged that broadcasters were refusing to cover the story of how Congress was attempting to make their fondest dreams come true. "It's a conflict of interest that they're resolving by non-coverage," said Nader. A press conference called by the NCCB and other groups opposing the abrupt changes in broadcast regulation was totally ignored by all the commercial networks and local stations -- except by Ted Turner's Cable News Network, Nader said.

At the press conference, Peggy Charren, president of Action for Children's Television, charged that the broadcast measures were being "railroaded" through Congress before the public could possibly know what was up. Asked about such charges yesterday, Bill Diefenderfer, chief counsel to the Commerce Committee, said, "That's bull----.That's just normal Ralph Nader stuff. We agree with Ralph Nader on most things, but this time we're not."

The dust, anyway, has just been settled on the great broadcasting caper of 1981, and the sound of popping champagne corks can be heard from TV and radio stations all across the land. For viewers, though, it's not even a good night for Lowenbrau; they've been had.