Jackson, Mississippi, of all places had a free-form FM station called WZZQ 102.9 FM during the 70's. We really didn't know how special it was at the time, thinking that any small-medium city would have the same thing.
It made such lasting impression on the local community that it spawned a documentary, released just a few weeks ago...more than 40 years after it went off the air (and changed to Country music)
https://pbs.org/video/wzzq-the-movie-pjg5oj