As digital terrestrial radio gets closer to launch, AM-only broadcasters are worried about the system's big problem: There's too much interference in the AM band to run a digital service at night.
At the annual National Association of Broadcasters conference in Las Vegas last April, Ibiquity Digital, the country's only developer of terrestrial digital radio technology, announced that the National Radio Systems Committee had endorsed its in-band, on-channel (IBOC) digital-AM technology, but only as a daytime service. NRSC, a group jointly sponsored by NAB and the Consumer Electronics Association (CEA), endorsed IBOC FM last November.
"In the implementation of IBOC, either FM or AM, there are certain, small trade-offs that simply must be made," said Milford Smith, chairman of the Digital Audio Broadcast subcommittee, in a speech at NAB. "In the case of AM IBOC, those trade-offs during daytime hours are minor and acceptable. During nighttime hours, the jury is still out, but enough caution flags were raised so that the working group was unable to recommend nighttime operation at this time."
Specifically, AM IBOC runs into interference when its signals hit what is called the "skywave," a near-vertical wave that is created when radio signals from huge 50-kW AM clear-channel radio stations bounce off the stratosphere. The clear-channel radio stations, so named because the government protects them from interference to keep the channels clear in case of national emergency, use the skywave to send their signals from Colorado to as far as California, for example. But all those bouncing waves seriously interfere with AM IBOC.
While that interference doesn't appear to be alarming to CEA, the FCC or NAB, it is to some AM broadcasters, who worry that they will be forced out of business.
"Ibiquity discovered this AM problem and didn't focus on it because they are FM-oriented," says Carl Marcocci, chairman and CEO of WGUL-AM and FM Group, Tampa Bay, Fla. "Maybe it just wasn't important to them. But it is important to AM broadcasters, who are the preponderance of independent radio broadcasters in the country."
Ibiquity President Bob Struble says Marcocci's fears are unfounded.
"We think the daytime-only solution is only temporary," Struble said. "We think there may be different issues with AM at night, and we want to test that, but we are absolutely confident that we will have a solution."
Ibiquity wants the FCC to approve a set of rules for digital radio by January 2003, when the company plans to roll out its first set of consumer offerings at the Consumer Electronics Show. The FCC has issued a rulemaking and will receive its first set of comments on the document on June 18.
Marcocci points out that Ibiquity was formed by the merging of three digital- radio companies: USA Digital Radio, Lucent Digital Radio and Digital Radio Express. Now Ibiquity is the only digital- radio company in the country, and it is owned by 14 of the nation's largest radio broadcasters—including Clear Channel, ABC, Bonneville, Citadel, Cox Radio, Cumulus Media, Emmis, Entercom, Radio One, Susquehanna Radio and Viacom. Ford, Gannett, Allbritton, Harris and several other technology and financial companies also hold stakes.
Marcocci is trying to put together an independent group of radio broadcasters, called the American Association of Independent Radio Stations, to lobby on such issues as AM IBOC interference.
"We are going to [create] the group and are going to die trying to get this AM matter solved," Marcocci said. "That includes getting the attention of Congress and the federal courts if necessary."
One issue Marcocci thinks the commission needs to consider is whether the FCC still should be protecting the skywave. "We don't need to protect a handful of AM stations to the detriment of everyone else."
The NAB Radio Board will be discussing the issue at length at its June board meeting this week, sources said. But NAB board members seem happy with NRSC's evaluation and trust that the committee would not have endorsed AM IBOC, even if only for daytime use, if it did not believe the system was nearly ready for service.