History of Rádio Muda

By: Martin Butera
From Brasília DF (capital of Brazil)

For most young people, radio has become a thing of the past, but I must remind all of them that not many years ago, using a radio transmitter to communicate was the only option for many social groups.

In this feature I bring you a report on one of the oldest university and free radio stations in Brazil, “Rádio Muda”, which broadcast since the mid-1980s inside the water tower of the State University of Campinas (Unicamp), in the state of São Paulo, Brazil.

Left, the water tank of the university. Right, we see the first students linked to the project at the beginning of the 90s (Public Archive of the station)

The beginnings

This is the story of a Brazilian university radio station, which undoubtedly exceeded the limits of the university and won the hearts and minds of many young people within Brazil and around the world.

Rádio Muda, became the most important university and free radio station and was one of the main references in free communication in Brazil and South America.

The history of Rádio Muda is quite messy, there are many versions and legends about the radio.

The name Muda, for example, is unclear where it came from or how it was formulated. At least 2 interpretations can be made, the translation from Portuguese to English would be the word “changes”, but an English translation of “speechless, dumb” could also be interpreted, supposedly because the station spent a long time like this, forgotten in a warehouse, unable to “speak.”

Leaving this aside, what is known about history is that radio was born from the experience of some Physics and Electrical Engineering students from Unicamp (State University of Campinas).

The State University of Campinas, (Portuguese: Universidade Estadual de Campinas) known as UNICAMP, is one of the public universities of the state of São Paulo, Brazil. Its main campus is located in the Barão Geraldo neighborhood, 10 km from the center of Campinas.

The Physics and Electrical Engineering students at the university, they built an FM transmitter and put it on the air a few times for little tests and it didn’t go beyond that.

The story goes that in the mid-80s, the first radio transmitter had about 3 watts and was built by a physicist, the study would have been set up, first where the university bookstore is located today.

It was not long and the transmitter was forgotten, until in 1991 when someone, rummaging through the warehouse or warehouse of the student center, discovered the transmitter and revived the old idea of ​​a university radio.

At first, only three students were involved in the University Radio project, in fact, very little could be done with a transmitter that barely carried its signal within 20 meters of the studio (the student center’s own warehouse or warehouse).

As some adjustments were made to the transmitter and the range was increased, the greater the number of participants.

Over time, students from other courses began to participate in the radio and proposed the creation of a student group to manage it.

Photograph of the first students related to the university radio project of the 90s, São Paulo, Brazil. (Public Archive of the station)

These students linked to the university radio project, with a perfect excuse, convinced the university rector that the student center needed a new tank and asked if they could occupy the university’s water tank, which was empty.

Without imagining it, the academic authorities were giving the students the perfect place to set up a radio station, now they had at their disposal a 50 meter high tower for their antenna, a small room of their own and with it the great desire to to become heard throughout the college campus and also to become heard outside the confines of the university.

This was not an easy task, as problems were arising, they needed a better, more stable and more powerful transmitter, since they would have a very large signal loss due to 50 meters of coaxial cable, and 3 watts was too little for their ambitions. .

After going through several self-built transmitters and improving the power, they came to have a 12 watt transmitter that was perfect.

Thus achieving the record distance of 3 km range, which they say was celebrated effusively when they achieved the initial goal of the radio; that the signal could be captured throughout the university campus.

Aerial view showing the large campus of Unicamp. On the right we can see the water tower indicated in the center of the campus square (credits: Itapira News / A Cidade On)

They then built a new transmitter with 40 watts of power, which was more than enough for their simple goals.

The new study of Muda was now in the tower nicknamed “Pau do Zefa” (in reference to the first rector of the University (Zeferino Vaz), so it was that a tower that used to function only as a water tank, became the headquarters of one of the main references in free communication in Brazil.

The emblematic water tank, where the station operated, inside the university (Public archive of the station)

In the mid-nineties, the group of young students who ran the station strengthened and young people began to arrive not only from the university, but also from the city of the entire district, the city of Barão Geraldo (where the university is located). ) and also from other neighborhoods such as Jardim Santa Ginebra, Vila Costa e Silva, Jardim São Marcos, Santa Mônica and the margins of the roads that cut the north of Campinas.

More than 250 people became linked to the station and the number only increased with each new university semester.

By the early years of 2000, Rádio Muda was the largest free radio in the country in every way: antenna height, transmitter power, number of air hours, number of participants and signal range.

However, this story would not end quite well …

The university announcers

Operating a free radio at that time in Brazil was a criminal offense (it still is, although there are already laws that support a little for those who build a free radio, just a little).

In those years the penalties were very harsh, two years in prison for anyone caught in the act.

Radio Muda, during its 30 years of existence, had many ongoing processes, although none were carried out.

Unfortunately, the university announcers were classified as criminals.

The Rectory of Unicamp never imagined that they had to have a project to implement a university radio on campus and when they realized it was too late, Radio Muda had taken on a life of its own.

The Federal Police of Brazil, in theory, can only enter the university campus with the authorization of the dean, which would not be interesting in terms of the dean’s image among the students, so many times the police and the communications secretariat were unable to be able to close the station.

For a long time, the students who ran the station were the ones who organized the student center at the university itself, so they had the situation under control for a while.

However, not all battles were won, raids were frequent and the transmitter was lost, and all radio equipment was seized.

Radio Muda university announcer

Inside Radio Muda

Image of the Radio Muda studio, inside the emblematic water tank, where the station operated, inside the university (Public archive of the station)

One of the only film materials that can be found on Radio Muda is a report produced by second-year journalism students from the Catholic University of Campinas (PUc campinas), it is a report dating from 2012, where you can see the Study of the station from the inside and how some of its students turn their backs to the cameras to hide their identity, which shows the degree of pressure that these students had to endure for fear of being criminalized for being Radio Muda announcers.

The video is in Portuguese, the images are more than eloquent and by watching it you can get an idea of what the station was.


Radio Muda operated during all its years mainly on the 88.5 and 105.7 MHz frequencies. Frequencies that were distant from the air communication band, which goes from 118 to 136 MHz.

Furthermore, any harmonic that Rádio Muda could produce was not within the range assigned for aircraft communication.

The transmitter used and built by the students themselves, generally used a harmonic filter (low pass) with high rejection (greater than 40db).

These transmitters were often built with the councils of electrical engineers from the university, who wanted to collaborate with the project in secret and although the assembly of the transmitters was very rustic, with the help of these engineers they were measured and adjusted using spectrum analyzers. and modern technical laboratory apparatus.

Image of the Radio Muda transmitter, self-built by students (Public archive of the station):
Another Image of one of Radio Muda’s transmitters, self-built by the students themselves (Public archive of the station)

That is why in all these almost 30 years of existence of the station, there was never a field measurement to prove any real interference caused by Radio Muda in airplanes or other radio stations.

However, under that excuse it was that the station constantly suffered raids and captures of its transmitters.

Anyway, something is true Radio Muda, during its almost 30 years it operated without authorization from the Brazilian National Telecommunications Agency (Anatel), although it is clear that this was not the reason for its constant “persecution”.

Many times the students camped in front of the water tank and resisted that the radio was not closed.

For decades, Radio Muda struggled to survive, actively fulfilling its role of guaranteeing university freedom of expression.

Thousands of voices passed through his studies that contributed to the production, dissemination and democratization of access to knowledge in various universities and for the internal and external communities of UniCamp itself.

Many times they were the ones who took the Radio Muda transmitter, but they could never take the voice of the students, who managed to get back on the air and thus free communication continued.

Students camping to resist a raid on the station (Public archive of the station)

Listen to Radio Muda

At that time it was not an easy task to tune the radio station over the air, it required a special technique that only those of us who love this type of radio know what it is about.

The silent radio was not pleasant to listen to, nor did it pretend to be, the radio was not prepared for listeners used to commercial stations, with the music of the moment and announcers with velvety voices.

Compared with the parameters of the commercial and most listened to radio stations, Radio Muda’s programs were nothing alike, they were messy, full of technical errors, had continuity problems and did not obey any conventional style.

Most people who listen to a conventional radio can simply do so with the station on while working, studying, reading a book, cleaning, cooking, etc.

However, if the radio was tuned to Muda radio, the listener was obliged to participate, to be active and to pay attention to the content produced.

Radio Muda was like a communication laboratory, it was a station of action built at all times, unplanned and collective throughout its almost 30 years of existence and resistance.

In Radio Muda there were no clear boundaries between music and voice-over, between reality and fiction. Radio Muda was a lot of beats, sounds and fragments … nothing was planned in the smallest details … nobody really knew what to listen to when tuning in the station …

Radio Muda managed to make its listeners, sooner or later, feel the special flavor of freedom.

Flyer of the station manufactured and distributed by the students themselves, these copies were made when some students secretly took the photocopier from the student center. (Public file of the station)

Final conclusion

Radio Muda, located in one of the water tanks of the State University of Campinas (Unicamp), in the state of São Paulo, Brazil, was a university communication school without knowing it.

The university never had undergraduate courses in communication, Rádio Muda offered wide access to the possibility of practicing radio production.

In Radio Muda, it was not necessary to have any type of diploma or previous qualification to enter the radio, and in it technical knowledge and styles of radio production were shared directly or indirectly.

In a Brazilian society, where the media is monopolized by economic and political interests, Radio Muda offered very diverse and creative programs.

The variety of styles of music and speech was so great that we can say that Radio Muda’s programming easily surpassed commercial radio stations in the city of Campinas, which was not something accepted by monopolistic stations.

Participatory organization and freedom of expression allowed a constant encounter with new intellectual, artistic and political raw materials, and the creation of new radio languages.

However, defining Radio Muda will always be a partial attitude and limited in scope in time and space, since nothing is recorded and there are different stories and legends about the station.

Satisfying those who read this report in Brazil will be a very difficult task, since each person who participated in the radio or each listener who ever tuned in to Radio Muda, will have their own version of it.

In principle, I believe that all those who knew Radio Muda will agree on a word called “freedom”, which was applied in the effort to guarantee that access to radio production is as wide as possible and that it is exercised with the minimum of restrictions.

Radio Muda, in Brazil, with its waves of freedom, challenged the Ministry of Communications many times with a low-cost FM transmitter.

Although in my opinion the students occupied themselves for too long only to create a kind of “civil disobedience” and although the radio was involved in other projects helping to set up a community radio for the city of Campinas and also a community television channel, the truth is that the station could never get out of the famous water tank.

As I mentioned earlier, the group of people at Radio Muda was made up of all those who wanted to be part of the station. Any student, teacher or employee of Unicamp could maintain a program on Rádio Muda.

Over the years, the students who run the station, without much experience, begin little by little to have proximity to different political movements and other people outside the university and they begin to get involved in the radio project.

I think that as a result Radio Muda gradually lost the anarchist and free or simply playful spirit with which it had been formed, which generated a clear conflict among the students themselves.

It is true that Rádio Muda in its almost 30 years of existence, had different ideologies since its foundation.

One of the main controversies was that despite always being in defense of university free expression through the radio, the students began to have contact with political organizations outside the university and somehow began to lose that naturalness. naivety and sincerity that represented radio and made it different from other stations.

When other political and social movements outside the university get involved in the students’ project, Radio Muda, they focus more radically on the fight to democratize information, making the station somewhat predictable and not very spontaneous.

The battle to uphold and defend these ideals is tough. The station ended up being unfairly singled out as something negative for the university field and ended up being criminalized.

At the end of 2017, taking advantage of the festive and empty period of the university campus, the radio studio was dismantled and its door sealed with cement.

At the beginning of 2018, the students found themselves instead of an entrance door, a concrete wall, which put an end at least so far to this experience of almost 30 years of Brazilian University Free Radio.

It was undoubtedly one of the most violent actions against radio, to date there is no information on the future of the station.

The sad end of Radio Muda, its door blocked. (Station’s public archive)

About the Author

Martín Butera is a founding member of Radio Atomika, a station that is part of the second generation of alternative, countercultural, illegal, free, self-managed radios, pirates born in the middle of Argentinazo 2001 (great Argentine economic crisis).

In 2013 to celebrate 10 years of the station (2003-2013), they edit a documentary called “Proudly Clandestinos”, a compilation with testimonies of the protagonists who worked at the station, which can be seen on YouTube in Spanish.

He left the project in 2017, when he went to live in Brasilia DF, the capital of Brazil, where he continues to work in alternative media.

Butera is also a radio amateur with more than 31 years of experience and has participated in DXpedition, throughout South America using the Argentine radio callsign LU9EFO and the Brazilian callsign PT2ZDX.

Martin Butera, is our correspondent for “Radio Heritage Foundation”, accredited in Brazil, he has also contributed to some of the most important international magazines and newsletters in the world on broadcasting, and his articles have been published and translated into several languages, such as Spanish, English , Portuguese, German and even Japanese.


This report is based on anonymous reports that were written during these almost 30 years of Radio Muda, some can be found on an old website of the station


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  1. (English version below Portuguese version)

    Olá! Meu nome é Gustavo, acabei de ler o seu artigo, que documenta muito bem a história desta rádio. Nasci em Campinas e vivi em Barão Geraldo até os 28 anos, eu ouvia muito a Radio Muda quando era criança. Depois que me mudei para São Paulo, só ouvi a Radio Muda quando estava visitando os meus pais.

    Apenas gostaria de acrescentar alguns detalhes:

    1 – Nos anos 1980-90, tinha um olho pintado na caixa d’água onde funciona a Rádio Muda. Quando eu era criança, me disseram que a Rádio se chamava “Muda” porque pintaram o Olho, mas faltou a boca.

    2 – Anos mais tarde, me disseram que a Rádio se chamava Muda porque quando o tanque d’agua esvaziava, fazia muito barulho, e as pessoas “interpretaram” que a torre da estação estava “tentando falar”, mas não conseguia porque era Muda. Esta versão eu fiquei sabendo por volta de 1999 e não me parece ser a versão original, portanto, eu fico com a primeira.

    3 – Essa é uma história há muito esquecida, mas era uma lenda urbana que matou todo mundo de susto: diz a lenda que estava acontecendo uma festa na Radio Muda e três caras resolveram subir os 50 metros da caixa d’água e nadar lá dentro. Uma vez lá em cima, só um teve coragem de entrar, os outros dois firacam olhando. O cara que entrou estava nadando de boa quando, de repente, o tanque começou a esvaziar muito depressa, ele se afogou e a cabeça dele ficou presa no encanamento, e teria demorado uns dias para recuperar o corpo. Essa história foi bem chocante na época, porque eu era criança e outras crianças tinham medo de tomar banho e sair sangue do chuveiro!

    4 – Uma vez, ainda criança, por volta de 1991 ou 92, sintonizei na Radio Muda e estava tocando uns ruidos esquisitos. Pensei que era uma transmissão alienígena! Mas na hora eu não tinha uma fita cassete para gravar os ruidos. Quando contei na escola que ouvi ETs falando pelo rádio ninguém acreditou… Por volta de 1995-96, quando eu usava computador com conexão dial-up pra acessar a internet, percebi que os ruídos eram parecidos com o que ouvi na rádio. Lá pra 2013, um amigo meu me disse que antigamente os caras transmitiam jogos de MSX… Demorou uns 20 anos para eu finalmente saber o que era!

    5 – Em 2015 gravei essa transmissão da Rádio Muda, que conta a história deles: https://youtu.be/-w2WZWbZfAI

    –[English version, ]–

    Hi! My name is Gustavo, I just read your article, which documents the history of this radio very well. I was born in Campinas and lived in Barão Geraldo until I was 28, I listened to Radio Muda a lot when I was a child. After I moved to São Paulo, I only listened to Radio Muda when I was visiting my parents.

    I would just like to add a few details:

    1 – In the 1980s-90s, the water tower where the Rádio Muda operates had an eye painted on the surface. When I was a child, I was told that Radio was called “Muda” (muted) because they painted the Eye, but the mouth was missing.

    2 – Years later, I was told that the Radio Muda was called like that because when the water tank emptied, it made a lot of noise, and people “interpreted” that the station tower was “trying to talk”, but it couldn’t because it was Muda (muted) . I found out about this version around 1999 and it doesn’t seem to be the original version, so I keep the first one.

    3 – This is a story long forgotten, but it was an urban legend that scared everyone to death: legend has it that a party was happening at Radio Muda and three guys decided to climb all the 50 meters of the water tank and swim inside… Once up there, only one had the courage to go in, the other two were left looking. The guy who came in was swimming well when all of a sudden the tank started to empty very quickly, he drowned and his head got stuck in the plumbing, and it would have taken a couple of days to recover his body. This story was quite shocking at the time, because I was a kid and other kids were afraid to take a bath and blood would come out of the shower!

    4 – Once, as a child, around 1991 or 92, I tuned in to Radio Muda and it was playing some weird noises. I thought it was an alien transmission! But at the time I didn’t have a cassette tape to record the noises. When I told at school I heard ETs talking through the radio, nobody believed… Around 1995-96, when I was using a computer with a dial-up connection to access the internet, I noticed that the noises were similar to what I heard on the radio. Back in 2013, a friend of mine told me that in the old days guys broadcast MSX games… It took about 20 years for me to finally know what it was!

    5 – In 2015 I recorded this broadcast of Rádio Muda, which tells their story: https://youtu.be/-w2WZWbZfAI