From November 20, 1969, the Indians of All Tribes occupied Alcatraz Island off the coast of San Francisco, California. The Alcatraz takeover was done to protest federal laws that contradicted historic land treaties with the Indians and aimed to destroy American Indian cultures, including the right of tribes to self-govern. This occupation was the first of its kind and inspired Native Americans to fight for their civil rights, as well as expose their issues to the North American public.
Radio Free Alcatraz was conceived to give a voice to the voiceless minority of Native Americans. On December 22, 1969, KPFA began its first live broadcast from Alcatraz under the direction of John Trudell with borrowed and donated radio equipment. The programs originated from the main cell block building on Alcatraz and were carried live by the Pacifica Network, which consisted, at the time, of KPFA, Berkeley; KPFK, Los Angeles; and WBAI, New York, weekday evenings at 7:15 p.m. PST.
SOURCE: https://www.pacificaradioarchives.org/recording/bb545701-bb545738