For a low-power FM radio station, anything measurable in miles is good.

But on a recent Thursday night, one station, KBFG, was struggling to even get on the air. The station's signal, audible since November in an area measurable in square blocks, had flatlined. The Ballard High School basketball team was about to take the court and the live play-by-play was in doubt.

"We're bootstrapping it," said Eric Muhs, a physics and astronomy teacher. Headphones were slung around his neck, and a mop of unruly gray hair came further undone as he leaned into his laptop trying to fix a software glitch. But Mr. Muhs, 60, one of KBFG's founders, admitted that the stakes for failure were relatively low. "Almost nobody knows that we exist," he said.