04.26.2006 08:00 AM
Unlicensed device bills threaten wireless mics

Wireless microphones at live remotes may be threatened by harmful interference from newcomers to the television band if House and Senate bills authorizing the use of unlicensed devices in so-called unused television spectrum become law.

Broadcast industry advocates met with Congressional staffers to discuss bills that would allow unlicensed devices to use portions of the television band for services like wireless broadband Internet traffic. The meetings raised the sensitivity of the staffers to the likelihood and the effects of such interference, but the bills are likely to move forward, said Association for Maximum Service Television president David Donovan.

Among the bills under consideration are the American Broadband for Communities Act introduced by Senator Ted Stevens (R-AK) and the Wireless Innovation Act of 2006 introduced by Senator George Allen (R-VA). A similar measure is proposed in the House.

The Stevens bill, for instance, states: “any unused broadcast television spectrum in the band between 72MHz and 698MHz, inclusive, other than spectrum in the band between 608MHz and 614MHz, inclusive, may be used by unlicensed devices, including wireless broadband devices.”

If enacted, the potential for interference to ENG wireless mics will increase. The most commonly used wireless mic VHF frequencies fall within 174MHz to 216MHz and on the UHF band from 470MHz to 806MHz.

While the Stevens bill specifically protects “incumbent licensed services operating pursuant to their licenses from harmful interference from such unlicensed devices,” Donovan said such post hoc protection will do nothing to prevent such devices from interfering with ENG wireless mics.

“With live news shots, you don’t have time to correct this,” he said. “With the wireless mic issue, you are live, on the air, and if it goes out, the harm is done.” He added that there was no room for mic failure while reporting on emergency situations, such as covering former New York City mayor Rudy Giuliani live on Sept. 11, 2001, or New Orleans Mayor Ray Nagin. “During an emergency situation, if those mics go out, their messages don’t go out.”

Tests show that out-of-band emissions, adjacent channel and co-channel interference from such unlicensed devices can cause interference from great distances — up to 10 miles in some instances, according to Donovan.

According to SBE Frequency Coordination Committee Chair Ralph Beaver, the assumption upon which the legislation is built is fundamentally flawed. “There are no unused TV channels,” he said. “They are dealing with something that doesn’t exist. Are they used 24 hours per day? No. Neither is a police radio. Does that mean we’ll let a new wireless service use on the police band?”

To date, eight consumer electronics manufacturers, the MSTV, NAB, the Association of Public Television Stations, the National Translator Association, the Community Broadcasters Association and wireless mic manufacturer Shure “have gone on record indicating these proposals would cause interference to TV sets or licensed wireless mics,” said Donovan.

A move to advance the legislation could happen between now and the middle of May.

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