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Proponents Hope for FM HD Asymmetrical Sideband Approval

iBiquity testing; FCC’s Doyle says agency interested in results

The FCC is watching HD Radio’s focus on asymmetrical sideband transmission, which proponents see as a way for more stations to accomplish an FM digital power increase while protecting a neighbor station at the same time from possible interference to his analog signal. The power increase was a much-discussed topic in many of the engineering sessions here at the Radio Show.

Some 150 stations transmitting their digital signal on symmetrical sidebands have implemented a digital power increase.

For those interested in asymmetrical sideband digital transmission, the commission is prepared to make the process more streamlined. WAMU(FM), Washington is the first station using asymmetrical sideband transmission.

During a regulatory session, Greater Media VP Radio Engineering Milford Smith said his company has applied for an STA to operate an HD Radio station using asymmetrical sideband transmission. Stations need an STA from the commission because the FM power increase approved earlier this year is only for IBOC transmission using symmetrical sidebands.

FCC Audio Division Chef Peter Doyle said during the session the commission would like to see more data on asymmetrical sideband transmission. “We’re interested in test results.” Once the agency sees what it needs to make a decision, the agency is prepared to make digital asymmetrical sideband transmission routine with a notification process, said Doyle.

IBiquity SVP/General Counsel Al Shuldiner said during a different technical session that the technology developer is conducting internal tests on asymmetrical sideband transmission and also on digital boosters and hopes to have results on both test topics to the FCC by the end of the year.