OK this TV show was in the late 80s early 90s. It was a group of kids that found an abandoned radio or TV station I can't remember.

The episode of "Saved by the Bell" titled "Saving the Max" was like that... if I remember right they found the schools old radio station equiptment down in the basement of the school and talked Principal Belding into letting them start the radio station up again. All of the 6 main characters took over a spot as radio host in their respective interests. I remember that Zach was the main DJ, Jessie did the main announcements and talked regularly about protests and saving the earth (true to her personality), Lisa did the gossip, Slater talked about the sports on campus, Screech told scary stories, and Kelly did "Desire Hour". I hope this is what you're looking for!

Sounds like the original Kidsongs series: YouTube - Original KidSongs TV Show from 1987 Part 1