Every Wednesday afternoon in a cramped two-room apartment off an alleyway in Prague's residential 4th District, several hundred supporters of the banned Jazz Section drop by to pick up the latest clandestine news bulletin and demonstrate their support for one of Eastern Europe's most defiant underground groups.

On sale under posters of John Lennon, Frank Zappa and other western jazz and rock stars is an eclectic assortment of publications featuring information about modern music, lithographs by abstract artists, an anthology about experimental theater in New York, uncensored prose and poetry, and cassette recordings of illegal bands.

The Czechoslovak regime has tried nearly everything to run the Jazz Section out of business, short of locking up the organizers. It outlawed the group. It dissolved the sponsoring Musicians Union. It intimidated printing houses that were publishing Jazz Section materials.

It launched a propaganda campaign against rock music. It eliminated the job the group's chief, Karel Srp, held at a state-run printing company. It froze the club's funds and demanded back taxes and penalties for alleged financial irregularities.

Still, the group manages to survive. How?

"This is very important for us," explained the 48-year-old Srp, earnestly waving a booklet containing the provisions of the Helsinki declaration on human rights.

The document, signed in 1975 by the Soviet Union, the United States and East and West European states at the Conference on Security and Cooperation in Europe, became a kind of bible for dissident movements throughout the Soviet Bloc, establishing a standard by which communist repression could be judged. Defensive Ploy

In self-defense, the Jazz Section joined the International Jazz Federation, a branch of UNESCO, figuring that an international affiliation would make the Prague regime more reluctant to suppress the group. So far, the ploy seems to have worked. The Jazz Section has been crippled but not totally quashed.

Today, the human rights struggle in Eastern Europe goes on.

After the military crushing in 1981 of Poland's Solidarity movement -- the Soviet Bloc's first independent trade union -- expectations for change were narrowed and time spans for reform extended. But to varying degrees, the spirit of resistance lives on in all six East European states.

As economic growth in the region slows, disaffection with the communist system deepens. In Poland particularly, the failure of the regime of Gen. Wojciech Jaruzelski to mount a substantial economic recovery since banning Solidarity has given rise this spring -- in the face of the third round of price hikes in three years -- to wildcat strikes and other signs of renewed worker restiveness.

International tensions over the continued deployment of nuclear missiles also have served to promote dissent. In East Germany and Czechoslovakia, the recent stationing of nuclear-tipped Soviet-made weapons has provoked unofficial attacks on Warsaw Pact policy.

Some dissident groups, searching for common ground with West European peace movements, are hoping to enlist those movements in pressuring Soviet Bloc regimes to honor commitments to human rights. This was the underlying message of the Prague appeal issued in March by some members of Czechoslovakia's best-known opposition group, Charter 77.

"The general idea is that peace in Europe is inseparably linked to observance of human rights," said Jiri Hajek, a former Czech foreign minister who signed the appeal with, among others, playwright Vaclav Havel, Jesuit priest Josef Zverina and leftist theoretician Petr Uhl.

"Our government is interested in dialogue with western peace groups. We think those groups should impress on our governments the need to observe certain standards of human rights."

The appeal went on to address another topic that is a current focus of dissident thought: the division of Europe.

No one expects any East-West lines to be redrawn in the foreseeable future. But some feel obliged to raise the issue, especially in this year of 40th anniversary celebrations recalling the defeat of Adolf Hitler's tyranny and the spread of Joseph Stalin's.

The 45 signatories of the Prague statement described their appeal simply as "an opening for discussion." They urged East and West to pursue cooperative arrangements that could erase Europe's split.

Among their suggestions were the start of talks between the Atlantic alliance and the Warsaw Pact about dissolving the two military blocs and withdrawing U.S. and Soviet troops from the territories of their European allies; the establishment of nuclear-free zones in Europe; an accord between the European Community and the Council for Mutual Economic Assistance (Comecon); reunification of the two Germanies.

While clearly utopian, the appeal drew some supportive echoes from other parts of the Eastern Bloc.

"The main subject in samizdat underground publications ," said Miklos Haraszti, an editor of a leading dissident journal in Budapest, "is that East European opposition movements should come up with formulas for a new European order. Nobody thinks the Soviets are ready to discuss the issue. But the logic is that the earlier one begins to speak to the Russians about it and be firm about the need for a discussion, the earlier they'll be ready to listen." 'Two Real Actors'

The last major attempt to reform a communist system from within was Alexander Dubcek's sweeping but short-lived bid in Czechoslovakia in 1968, which the Soviets strangled. Since then, opposition movements have stayed outside communist establishments and official structures.

The intention of these dissident groups has not been to cause revolutions and overthrow states or to compete with existing institutions.

Rather, as described in an essay by Jan de Weydenthal, a senior Polish analyst at Radio Free Europe, their aim has been to point out deficiencies and failures in official policy in hopes this will lead to corrective actions and the internal evolution of communist systems.

This approach was in effect a kind of sidelines strategy. But the rise of the Solidarity movement added a new dimension in Poland. It marked the passage of opposition activists from the status of powerless dissidents to major actors on the political stage.

"Previously, opposition movements had sought improvement, not change," said Mihai Botez, a mathematician and futurologist who is one of Romania's most celebrated dissidents.

"We envisaged at best a sort of benevolent dictatorship. But Solidarity was the first to stand up and demand a dialogue with the authorities and respect for itself as a player in the game. For the first time, there were two real actors."

The elimination of the union dashed hopes that pluralistic politics could take hold in the Soviet Bloc. When searching now for an optimum model of relations between a communist regime and society, East European and western analysts point to Hungary. There, party leader Janos Kadar has generated a high degree of conformity without barring dissent entirely.

Parliamentary elections just held in Hungary required for the first time that at least two candidates run for each seat. More significantly, a rules change permitted the nomination of candidates from the floor at neighborhood caucuses.

Party officials proved adept at blocking dissidents who tried to test the real openness of the electoral reform.

Nominating sessions in Budapest's 5th District were packed with party loyalists on the evenings two prominent opposition figures -- philosopher Gaspar Miklos Tamas and architect Laszlo Rajk -- sought to get elected. Nonetheless, the formal invitation to nonofficial candidates seemed to be a way to give various interest groups a chance to express contrary views. Despite its reputation as the bloc's leading reformer, Hungary shows little sign of evolving toward a multiparty system. Instead, the trend there is toward a corporative model -- representation based on special interest groups, such as trade unions, youth groups and artistic associations. The corporative form preserves the party's power monopoly, but carries an air of democracy.

While all East European regimes are hostile to dissent, they vary in the harshness with which they deal with opponents. Poland and Hungary are the most restrained; Romania is the most oppressive.

Some dissidents consider themselves fortunate still to be alive. "There is a certain progress in that we still exist, that we haven't been dissolved," said Hajek, a founder of Czechoslovakia's Charter 77, Eastern Europe's longest-surviving human rights group. "The potential repercussions of getting rid of us have persuaded the regime it would not be advantageous to do so."

Western concern is not the only factor making Eastern Bloc regimes more hesitant to terrorize their critics. Other considerations cited by specialists include government interest in maintaining a semblance of social peace and a reluctance to take the opposition seriously.

"We realize that some of these people are simply lost," said Poland's interior minister, Czeslaw Kiszczak, in a recent speech. "That is why we do not always decide to eliminate all manifestations of clandestine activity . . . . We only put a stop to extreme and dangerous activities. "Domestic Focus

Not all dissent is organized. Much of it gets expressed in nonorganizational forms -- through widespread grumbling about life under socialism, for instance, or graffiti on walls. Workers frequently show their discontent through low productivity, high absenteeism and general apathy. Alcohol addiction rates in the Soviet Bloc run among the highest in the world.

Where opposition is organized, there has been some similarity among national groups. Committees dedicated to monitoring abuses and publicizing official infringements exist in Poland, Czechoslovakia and Hungary. But for the most part, dissident movements have stayed focused essentially on political conditions in their own states.

Poland remains the most restless case in the communist camp. Unofficial lectures and discussion groups, often on taboo subjects, take place frequently, and underground cabarets and other artistic productions are not uncommon. Illegal literature circulates widely. Opposition activists operate throughout the country, attempting to build professional and artistic groups to parallel the official ones.

"The underground operation is much more developed than it was before the rise of Solidarity," said Krzysztof Sliwinski, a Roman Catholic intellectual. "Now it's a business, like the black markets. This ensures it will stay."

Poland's Roman Catholic Church shelters much of the opposition activity, and priests' sermons are a frequent source of public criticism of the regime.

"As long as people here don't have the opportunity to form the organizations they want, the church will be pushed into an opposition role," said a senior aide to the Polish primate, Cardinal Jozef Glemp. "The more repressive the authorities are, the more people will be driven to the church."

At the moment, the contest in Poland appears stalemated. Authorities concede they aren't winning converts, but they say Solidarity's popularity has worn thin, leaving a growing middle ground of uncommitted Poles. But some opposition activists insist that society's patience with the Jaruzelski regime is running out.

Predictions vary widely about how long the current standoff can last and what might happen next.

"I can't imagine a future in terms of a new Gdansk agreement, with two sides, one table, all that atmosphere," said Bronislaw Geremek, a historian and former top Solidarity adviser, referring to the 1980 shipyard strike that led to the independent union.

"But that pattern does offer something for the future, in the sense that the only way out of the crisis is through a dialogue, a dialogue in another way than August 1980 but with the same spirit, a feeling of necessity to strike a deal, a feeling of the need to give something to get something," he said.

In Czechoslovakia, the harsh experience of the 1968 Soviet invasion and subsequent normalization process has caused the public to recoil from political involvement. Most have chosen withdrawal into private activities and consumerism.

Yet the Charter 77 movement carries on. It is a constellation of people, now numbering 1,200 signatories from various political and religious backgrounds, pressing the regime to comply with international commitments to human rights.

Samizdat literature published under the name "Padlock" circulates in Czechoslovakia in the form of typewritten manuscripts, passing from hand to hand. An underground church has emerged as well, supported by Prague's outspoken, aging Cardinal Frantisek Tomasek. Followers typically meet in homes for prayer sessions and mass, sometimes conducted by priests who have been secretly ordained.

In Hungary, dissident activity is confined to a small group of intellectuals and is centered around underground journals -- most notably A Hirmondo (The Messenger) and Beszelo (The Talker). They have drawn attention to allegations of mistreatment of Hungarian minorities in Romania and Czechoslovakia. They have also called for a public reassessment of the factors behind the Soviet suppression of Hungary's 1956 rebellion.

In East Germany, Protestant churches shield a movement that questions the nuclear military policies of the Warsaw Pact as well as the Atlantic alliance. Some Protestant synods have denounced the stationing of new Soviet battlefield weapons in the country.

In Bulgaria, there is little sign of dissent, though several mysterious bomb explosions last year were widely believed to have been politically motivated. Two of the devices -- one at the airport in Varna and another at the railway station in Plovdiv -- went off Aug. 30, the day Bulgarian leader Todor Zhivkov traveled from Varna to Plovdiv.

In Romania, where living conditions are the harshest in Eastern Europe, there has been no major reported worker protest since a 1977 strike by coal miners in the Jiu Valley over food shortages and poor conditions. An attempt two years later by a small Bucharest group of intellectuals and workers to form a free trade union was quickly smothered by the jailing of the leaders of the initiative.

Mikhail Gorbachev's election as the new Soviet leader has stirred hopes of at least technocratic reforms throughout the bloc, possibly with some democratic elements. But in the region's dissident communities, there is little expectation that Gorbachev will promote political liberalization.

It seems inevitable the bloc will continue to be marked by an uneasy peace, with small opposition groups carrying the banners of human rights and a united Europe against their unelected governments.

"We have no illusions for ourselves that we'll have a repetition of the Prague Spring," said the 72-year-old Hajek, looking weary but sounding wise. "Gorbachev has an interest in keeping the empire quiet as he tries to reform the Soviet Union and consolidate his own power."