Mr. Fass sometimes used the airwaves to rally his listeners to action. One event he organized was a “sweep in” in 1967 to clean trash on the Lower East Side. “Amid chants of ‘Love,’ the clash of cymbals and the throb of bongo drums, about 200 young people plied brooms, mops, dust cloths and shovels yesterday,” The New York Times reported, adding, “One group attacked a large mound of broken wood and plaster in front of a tenement house while astounded men watched from windows of the Department of Welfare shelter across the street.”

Many of the recordings, including one that described the cleanup, were thrown out by WBAI in 1977 after Mr. Fass was banned from the air for five years as a result of an internal dispute of the sort that has periodically convulsed the station. Mr. Fass recovered the recordings from the trash, then stored them in the attic of his house on Staten Island. Later, a friend, Caryl Ratner, arranged for them to be placed in a climate-controlled warehouse. Several years ago two filmmakers, Jessica Wolfson and Paul Lovelace, along with Mitch Blank, a longtime music cataloger, transferred some tapes to a digital format for use in a documentary about Mr. Fass.

That material turned over to Columbia offers a preview of the wider trove. It includes performances by musicians like Muddy Waters and Phil Ochs. There are also conversations with the poet Allen Ginsberg and the boxer Rubin Carter. Some tapes contain Mr. Fass’s reports from the 1968 Democratic National Convention, in which he narrated turbulent conflicts between the police, National Guard troops and protesters in Chicago. “You can hear them — you can hear the reports of the gas grenades all up and down the streets,” he says at one point as booms and shouts echo in the background. “The crowd is being pushed back, and the gas is coming.”

Mr. Fass, 83, has not been inside the WBAI studio recently and now broadcasts the show over the telephone or from a studio inside his home. He still draws callers, though perhaps not at the volume he did several decades ago.

In a phone interview, he said the tapes that went to Columbia included recordings describing the takeover in 1968 of buildings there by students protesting the construction of a school gymnasium in a public park and the school’s affiliation with military researchers. Perhaps, he suggested, those recordings would resonate with contemporary students.

“When history is recovered it has a way of influencing the present,” Mr. Fass said. “I hope students at Columbia are informed by the compassion of what came before them.”