In Tetsuo Kogawa 80 years life, teaching and directing turned out to be a joke. He has been more involved in transmission: writing, free (emancipating and costless) radio, media performance and radioart (from 'radio without contents' to radiation-art).
MAKE ME A SIGNAL Preludium für ein RADIOTOPIA (2021)

After studying philosophy at Sophia(Tokyo) and Waseda universities, Tetsuo Kogawa spent many years in New York City. He taught at Wako University(1972-1989), Musashino Art University's Department of Video and Cinema (1989-1994) and Tokyo Keizai University's Department of Communication Studies (1994-2012). Kogawa introduced free radio movement to Japan, and is widely known for his blend of criticism, performance and activism. He has written over 30 books and numerous articles on radio art, media culture, film, city and urban space, and micro politics. He has shown his artistic and useful workshops to build Mini-FM and microradio transmitters in many cities of Canada, US and Europe. Most recently he has combined the experimental and pirate aesthetics of the Mini-FM and microradio technology with internet streamin media in such projects as "Radio Party", "Translocal Palimpsest", and "Radio Kinesonus".
He was invited by The Banff Center of the Arts, Western Front, Next Five Minutes, Bauhaus University, Kunstradio, Tate Modern, Walker Art Center, Govett-Brewster Art Gallery, Deep Wireless, Musicprotokol, AV Festival, Instal, Cut & Splice, FON and so on.
See other sources on him: Yahoo.com  Google Books.

Tetsuo Kogawa is a performance artist who—aside from being a university professor in the Department of Communication Studies at Tokyo Keizai Universiuy, the director of the Goethe Archive Tokyo, and a prolific writer on media philosophy, information technology, film works, Kafka, and various contemporary themes—has been teaching workshops for many years, showing people how to build their own FM transmitters from simple electronic components. These workshops also provoke those involved to consider the technical, political, and social ramifications of electromagnetic broadcasts. By building transmitters the workshop participants inevitably deconstruct broadcasting, challenging their own notions of what broadcasting is now and whiat it could be. He has been likewise challenging radical experiments of radio art using and exhibiting his invented devices in various cities of Europe and North America. Since the mid-nineties, he has also been involved in creating and organizing his own webpages. http://anarchy.translocal.jp
(RE-INVENTING RADIO Aspects of Radio as Art, Revolver, Frankfurt am.Main, 2008)

Who is this person? Tetsuo Kogawa is a really very influential figure in underground radio art and media-art theory, with over 30 years of collaboration and connection with some of the most influential artists and thinkers of that period, worldwide[1] .
He's perhaps best known internationally as the founding father of the micro-fm boom in Japan in the 1980s. Inspired by 'Autonomia' movement and their pirate radio stations in 1970's Italy, Kogawa set up Radio Home Run as a resistance to the commodification of subculture; theorising, practically enabeling and kick starting a Japanese boom which saw thousands of tiny radio stations set up and run, by and for communities across the country. They became a space for polymorphous chaos, a kind of chaos found through difference and "order through fluctuations."
What is he doing? Like loads of people at the festival, Tetsuo Kogawa is interested in potential: the potential of radio and broadcasting as an artistic and political medium. Here is a direct quote from him. "Throughout its history, despite efforts by the Futurists in the 1920s, radio has been considered largely a means of communication rather than an art form. Therefore, it is ironic that just as traditional forms of radio are in decline, its possibilities as an art form are reaching extreme potentials. If, as Heidegger[2] suggests, extreme possibilities are reached at the end of something, what then ends with radio? What is radio's "most extreme possibility?"
Why is it interesting? Well, I just think Tetsuo Kogawa is an extremely interesting thinker who applies deeply significant trains of thought to artistic practice as it reflects on, engages with and aspires to change the world. We shouldn't be ashamed to ask for this kind of engagement. I don't really think of Tetsuo as a musician, or sound artist; he is a radio artist, part of which crosses over into performance. Here's two ways he brings radio art into performance.

[1] He's published over 30 books, had a series of interviews with Félix Guttari, has known and collaborated with pioneers of experimental music in Japan from the 50's on (big guns like Yasanao Tone and Takehisa Kosugi and so on)
[2] And here's a direct quote from Heidegger (wrote Being and Time ? a very influential 20th century philosophical work on what being in the world means and sort of discussed very briefly already in this booklet ? see Hermann Nitsch): "We understand the end of something all too easily in the negative sense as a mere stopping, as the lack of constitution, perhaps even as decline and impotence, the end suggests the completion and the place in which the whole of history is gathered in its most extreme possibility."

Barry Esson, the director of Instal in "Instal 09" catalogue, 2009