The Federal Communications Commission yesterday approved a new kind of radio station--low-power FM--in a move hailed by neighborhood activists and blasted by existing radio stations.

The new stations would vary in strength from one watt to 100 watts, compared with 6,000 watts for the smallest FM stations now allowed. The largest low-power station would have a broadcast reach of about three miles; the smallest, several blocks. The FCC will begin accepting low-power applications in May, and the new stations could hit the airwaves by late this year.

With bargain-basement equipment, the stations could cost as little as $1,000 to start, say low-power advocates. Under the regulations, there could be more than a thousand 100-watt stations across the country. Washington could support three or four 100-watt stations and, presumably, a handful of smaller-power stations.

Low-power FM is potentially the biggest change to hit radio since the ascent of FM in the '60s. Over the past few years, Internet-only radio stations have blossomed around the globe, but their programming is accessible only to those who can afford computers. Theoretically, low-power FM stations--broadcasting news, music and commentary to individual neighborhoods--could be heard by anybody who can afford a cheap radio.

For more than a year, FCC Chairman William E. Kennard has pushed the issue, saying the new stations will increase diversity on the airwaves. Existing broadcasters--led by their trade group, the National Association of Broadcasters--fought the idea, saying the new stations will cause interference on an already crowded FM band and hamper the upcoming conversion to digital broadcast signals.

FCC commissioners voted 4 to 1 for low-power. Kennard and commissioners Gloria Tristani, Michael Powell and Susan Ness voted in favor, while commissioner Harold Furchtgott-Roth voted against.

"This will empower people to more effectively use the public airwaves to build stronger communities," Kennard said after the vote. "There has been an outpouring of support from around the country, from really diverse communities, such as the Creole-speaking community in South Florida and the Vietnamese community in south Texas."

NAB President Edward Fritts issued a terse statement in response to the vote:

"The FCC has turned its back on spectrum integrity. Every legitimate scientific study validates that additional interference will result from [low-power FM]. This FCC has chosen advancement of social engineering over spectrum integrity. It's a sad day for radio listeners."

The NAB will consider pursuing a court order to stop low power and likely will push a November resolution sponsored by Rep. Michael G. Oxley (R-Ohio) to prevent the FCC from establishing low-power FM.

The FCC wrote strict rules for low-power ownership: The stations cannot sell advertising but can seek underwriters, as does public radio. No existing broadcaster can own a low-power station. During the first two years of low-power radio, station owners must be headquartered within 10 miles of the station. Also during this period, there can be no multiple ownership of stations. And low-power licenses will be nontransferable.

In Mount Pleasant, Amanda Huron was ecstatic over yesterday's ruling. She teaches radio production to neighborhood kids and plans to be among the first applicants for a low-power license, to broadcast to Mount Pleasant, Adams-Morgan and Columbia Heights.

Her group--the Mount Pleasant Broadcasting Club--already has a studio on Mount Pleasant Street as well as a program lineup for its yet-unnamed radio station: youth-oriented shows by teens from the Latin American Youth Center and Martha's Table. Jazz. Hip-hop. Go-go. Live music by local musicians. Live ANC meetings. Poetry slams. Spanish-language programs from labor unions.

She has even received her first donation of music: a "huge slew" of CDs from Dischord Records, the Arlington punk label.

"I was really pleased with the emphasis that the [FCC] officials kept putting on the importance of community voices being heard," Huron said. "They've been cut out of mainstream media."