High in the Sierra Madre where Mexicans speak no Spanish and celebrate mass by killing a chicken and passing the fire water instead of sacramental wine, there is a radio station that brings only good news.

Inside a small shack that hovers on a high rock over this town and serves as its broadcast studio, a young Indian in jeans pulled up a chair, threw a switch and went on the air.

He spoke in fast, singsong tones, pierced with hissing sounds. The language, Tijolabal, an offshoot of Maya, is one that few people in the world can still understand.

A new school would be opened by the state governor that day, he told his listeners somewhere over the hills, and the president of the republic was visiting a dam. There was not a word about the schoolteachers who had seized the town hall at nearby Chenalho in a protest, or about the mayor of Syola who, in the midst of a scandal, had been forced to resign.

As a young technician put on a tape of cheerful marimba music, the announcer explained: "We don't do sensitive or sensational news. We have government propaganda, good news and useful information." To illustrate his point he showed a list of programs, on subjects like how to cope with coffee rust, curing snake and tarantula bites, using fertilizer, Spanish lessons and whether to get birth control advice.

He bent over the microphone again and spoke in another set of clipped tones that sounded vaguely Chinese.

"He says that marriage is no longer valid if one of the two people is already married," someone translated, "and taht it is also forbidden if a boy is less than 16 and a girl less than 14 years old. But people around here don't always know how old they are."

The three small cubicles overlooking San Cristobal are a remarkable government institution called Radio Indigena, or Indian Radio. Its powerful transmitters beam into the far corners of the forests, all the way to the valleys on the other side of Ciapas, Mexico's most Indian state.

By 5 a.m., when the Indian villagers are well into their day, Indian Radio starts broadcasting in the Tzotzil language, then switches to an hour of Tzeltal, of Zogue, Chol and Tojolabal.

All five are branches of the Maya language that was spoken in the once magnificent towns of this region 2,000 years ago. Since then, they have turned into mutually unintelligible tongues spoken by about 250,000 people spread over hundreds of Indian communities.

This Indian Radio and the three other stations in Mexico that broadcast with United Nations equipment in some of this country's 58 Indian languages, are virtually the only consistent contact with the outside world for many of Mexico's 7 million Indians. The power of these stations -- their potential use and abuse by the government -- is a subject of passionate debate among anthropologists.

There is general praise for the station's ban of commercials and their daily dose of "how to" programs on problems that are very much part of the Indian world.

But critics, including both Mexican and foreigner anthropologists who observe, study and write on this Indian world, worry about the government being the sole arbiter of what information is "good for the Indians" and its role as the dominant interpreter of the reality outside the Indians' magic universe.

The radio programs, so these critics say, also serve the government's policy of integrating the Indians as Mexicans into one Mexican nation.

"On the one hand the station carries folk tales and Indian music to echo the Indian identity," said a European anthropologist who knows the region well, "but ethnic awareness and pride in the true sense is definitely discouraged. The heroes presented in the history programs are national figures, people who have little in common with the Indians. There is no attempt to present local leaders either present or past."

The response of the National Indian Institute to such changes is that the government has no right to cut the Indians off and must provide a "national" option. Moreover, the Indians have "other interpreters of outside life. Just look at the range from progressive Catholic priests to conservative fundamentalist Protestants working among them," one institute official said.

There are no ratings to measure the number of listeners of Indian Radio. More and more, the station's workers say, Indians carry small transistors in their traditional shoulder bags while they herd their animals or till their land.

"We know the power of the station is tremendous" said Heriberto Velasco, who works as one of the few Spanish-language announcers. "Last year a national bicycle rally was to pass not far from here. We did a program explaining what a bicycle rally really was. Thousands of people who would have never known about it came to watch."

A more poignant example of the radio station's impact occurred recently when a call was broadcast that in Tuxtla, the state capital, a meeting would be held for people interested in regularizing the titles to their land.

"Over 20,000 men showed up in Tuxtla. Many had walked and traveled on buses for up to two days," said Velasco.

The daily press available to San Cristobal's citizens who read Spanish is either El Sol, whose editor doubles as the state's governor's press secretary, or the papers from Mexico City, the arrival of which depends on the vagaries of the weather or other airline tribulations.

The news that is not fit to print in those newspapers comes off a mimeograph machine. Routinely, students hand out blotchy, homemade leaflets on the narrow colonial streets or toss them through car windows. They are complaints about action by police, Army or other branches of officialdom, about land or union squabbles or peasants unjustly jailed. Justice, or rather, the absence of it, is the most widely used word. A half-page pamphlet on a land dispute used the word 17 times.

Under the auspices of the local bishop, Samuel Ruiz, a critical magazine, The Parrot, is published. It appears once a month and consists of cartoons aimed at giving a nonestablishment version of politics.

A local maverick, Amada Avendano, along with his wife and a few friends, has started a local weekly newspaper. They all work "for free" he says, "as a hobby, a sport, or for love of the truth, if you like."

On Tuesday morning, when El Tiempo comes out, Avendano's paperboys sell about 1,000 copies at 12 cents each. This money, and the income from the ads, permits the paper to break even, he says.

For real income, Avendano, who describes himself as "progressive but independent," has a small law practice and teaches a few courses at the university. He has just finished translating the Mexican constitution into simple lay language, "which ordinary peasants can understand."

"Since we are not going to have another revolution in this country, fighting with the constitution is the only way the poor can defend themselves," he says.

On a recent hectic Monday night, Avendano walked excitedly around the one room where the paper is written, made up, set and printed.

"Look what I just found in a closet. This place used to belong to the government." Avendano was holding a photograph of five Indians, all with their ears cut off.

"It must have been taken around 1916, in the revolution. That's what happened to the Indians if someone decided they were fighting on the wrong side. Of course, the poor SOB's had been press-ganged. They had no idea which side was which."

The photo had to go into the paper, Avendano decided, mixed in with local news about the teachers who had seized Chenalho town hall and another land dispute.

In Mexico City, Avendano mused, there is just about total press freedom, but the provinces have their own rules. He has to tiptoe, or even sidestep when it comes to reporting on the behavior of government officials, and "I have to very indirect or silent when it comes to abuse by the military."

"I love my paper, it's my passion," said Avendano and beckoned his visitor to follow him outside to where his car was parked. "It happened on July 26, 1980. I had criticized some policies of the state government."

In the dark, Avendano pointed at the bullet holes in the left door of his car.

"They sent me a warning," he said, "I guess I can take a hint."