By Adrianne Kroepsch, CQ Staff

In an effort to recreate the success of Wi-Fi, but on a much broader and faster scale, the Federal Communications Commission appears poised to open unused television airwaves to unlicensed wireless devices.

A controversial agency decision on the matter — known in industry parlance as “white spaces” — is scheduled for Tuesday.

FCC Chairman Kevin J. Martin has said he supports opening white space frequencies to next-generation wireless devices, and it appears the agency is preparing to do so.

Martin’s optimism is based on the recent conclusion, by agency engineers, that white spaces devices could operate without interfering with existing TV signals — and it has prompted an eleventh-hour lobbying flurry.

TV broadcasters afraid of interference with their signals and wireless incumbents who want the spectrum to be licensed are both vehemently opposed to the idea of white spaces use. Wireless microphone users also have jumped in, saying that unlicensed devices could interfere with their similarly unlicensed microphones, potentially impacting business on the stages of Broadway, the sidelines of the National Football League and elsewhere.

House Energy and Commerce Chairman John D. Dingell wrote the agency to ask it to take extra steps to mitigate incumbents’ interference concerns. He also asked the FCC to consider licensing some of the spectrum. The FCC typically auctions wireless licenses for billions of dollars, which goes to the Treasury.

Senators Hillary Rodham Clinton , D-N.Y., Mary L. Landrieu , D-La., and Wyoming Republicans Michael B. Enzi and John Barrasso also have written the FCC to express concern.

Walter Liss, president of ABC-owned television stations, Friday submitted perhaps the shortest comment of all for last-minute FCC consideration, asking only: “Are you really prepared to authorized millions of unlicensed personal/portable devices in the TV band based on the hope that none of them will ever break and cause untraceable interference to consumer TV reception?”

A positive vote could essentially turn the digital communications landscape on its head by opening access to coveted wireless frequencies traditionally held only by high-paying telecommunications companies. High tech firms like Google and Microsoft want to see more competition in the wireless broadband market. Joined by other Silicon Valley players, they have been lobbying hard in favor of white spaces use.

In a rare agreement between rivals, Google chief executive Eric Schmidt and Microsoft Chairman Bill Gates are both convinced that white spaces use could transform the way people connect to the Internet — making wireless access cheaper, faster and easier, and sparking technological innovation globally.

“The time for study and talk is over,” Schmidt wrote to Martin late last week. “The time for action has arrived.”