Interference questions dog broadband over power lines

The FCC has been seeking public comment on the technology since last April

Ham radio operators and at least one U.S. federal agency contend that the transmission of broadband over power lines interferes with their radio signals, and if the radio operators have their way, the emerging technology that's meant to give Internet users another broadband service choice might not get off the ground in the U.S.

The American Radio Relay League (ARRL), a national ham radio association, and the Federal Emergency Management Agency are among the organizations that have raised concerns with the Federal Communications Commission over possible shortwave radio interference caused by broadband over power lines, often called BPL.

Companies experimenting with BPL, which uses traditional power lines to transmit data over the Internet, have promoted it as an inexpensive-to-deploy alternative to cable-modem or Digital Subscriber Line services.

Some BPL supporters champion it as a way for broadband to reach rural and other areas with limited broadband service because of the near ubiquity of power lines.

The two sides are far apart on the interference issue, which the FCC is examining in a request for public comments that has been ongoing since last April. The ham radio association says it has found radio interference in every place it has tested short-wave BPL systems, while representatives of the BPL industry say they can't find interference caused by their systems.

The FCC's rules already prohibit unlicensed electronic devices, including BPL transmitters, from interfering with licensed devices, such as ham radios. If the FCC were to find interference and enforce its existing rules, most of the BPL industry could be shut down. "If the commission were to follow its rules, that would be the practical effect," said Dave Sumner, CEO of ARRL. "If the commission decides that BPL cannot operate in this country, that'd be fine with us."

Most BPL vendors use devices called repeaters to amplify and clean up the data signal carried on power lines, and those devices, as well as BPL modems, emit frequencies in the same range as radios used by ham radio operators and some emergency responders, according to the ARRL. Some BPL vendors are experimenting with devices that use microwave signals; the ARRL says those devices wouldn't interfere with ham radios.

But Current Technologies LLC, which offers BPL service in the Cincinnati and Rockville, Md., areas, can't find interference caused by its system, said Jay Birnbaum, the company's vice president and general counsel. Current Technologies uses a technology standard called HomePlug, designed to not interfere with other radio signals.

"[Interference] just doesn't exist," Birnbaum said. "They based a lot of their assumptions on outdated noise flow analysis."

Birnbaum accused the ARRL of being overprotective of its turf. "The decision-maker here is not the ham radio community -- the decision-maker is the FCC," he said. "It's been [the ARRL's] policy to oppose any new technology that causes emissions, whether they be harmful or not." The ARRL maintains a Web page listing BPL as one of nine technologies it calls "threats to our amateur bands."

It doesn't make sense for BPL companies like Current Technologies to move forward with their business plans and financing if they're causing interference, Birnbaum said, because the FCC could immediately shut them down if they did. Any interference the ARRL is measuring might be coming from other licensed radio devices, he said.

"If it turns out I'm trying to make a device or sell a device that would cause interference anytime it's used, it kind of belies logic that I could raise money to do that," Birnbaum said.

The ARRL has posted a video on its Web site showing interference in four BPL test areas, including Current Technologies' Maryland location. "For them to say that [they don't cause interference] shows they don't know what they're talking about," Sumner said. "It's a classic case of denial. We'd be glad to go down and show them the interference we've observed on their system."

If the FCC were to enforce its existing rules against interference, the ARRL would be happy, Sumner said. The ARRL became concerned that the FCC would relax its interference rules when commissioners praised BPL during a commission meeting in April, he said. FCC Chairman Michael Powell called BPL a "monumental breakthrough in technology."

"The benefits don't outweigh the negative consequences," Sumner said. "You're taking a part of the radio spectrum that's unique. It's the only part of the radio spectrum that supports communications long distance without infrastructure."

The FCC has received about 5,000 comments on BPL, and a possible next step would be to issue a notice of proposed rulemaking later this year, if the commission determines new rules are needed for BPL, an FCC spokesman said. Last month, the Federal Emergency Management Agency filed comments saying BPL could "severely impair FEMA's mission-essential HF [high-frequency] radio operations."

The National Telecommunications and Information Administration at the U.S. Department of Commerce is conducting its own study, and Phase 1 is due out in the first half of 2004. The agency is attempting to address the balance between accommodation of BPL and protection of vital federal and private services, according to an agency spokesman.

The FEMA objections simply repeat the concerns of the ARRL, said Brett Kilbourne, director of regulatory services and associate counsel at the United PowerLine Council. The FCC should allow BPL to continue operating after it's finished researching the issue, he said.

"Our experience in the field contradicts what [the ARRL is] alleging," Kilbourne said. "We're entirely satisfied that there won't be any interference."

Copyright © 2004 IDG Communications, Inc.

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