-By Katy Bachman, Mediaweek

WASHINGTON The Federal Communications Commission may not have authority to investigate Arbitron, but it set comment dates to address the emergency petition filed by the PPM Coalition and the Association of Hispanic Advertising Agencies.

The two groups, made up of a number of Hispanic broadcasters, as well as urban broadcaster ICBC Broadcast Holdings and the National Association of Black Owned Broadcasters, filed a petition earlier this week requesting the FCC investigate the accuracy of Arbitron's portable people meter technology.

In addition to its PPM markets in Houston and Philadelphia, Arbitron plans to commercialize eight markets Oct. 8, including New York, Chicago, Los Angeles and San Francisco.

The two petitioning groups claim that Arbitron's PPM methodology does not adequately sample ethnic audiences and that subsequent ratings will seriously harm minority broadcasters.

"A Section 403 inquiry is the only way the commission can shed light on the methodological problems identified in early PPM markets and avert harm to minority broadcasters from a rollout of PPM with a flawed methodology that undercounts minority audiences," the groups wrote in their petition.

The commission moved at lightning speed. Comments on the petition are due to the FCC by Sept. 24, and reply comments are due Oct. 6.

Arbitron continues to maintain the FCC, which regulates the nation's airwaves, does not have jurisdiction over media research firms.

--with additional reporting by Julie Gidlow Radio and Records