Broadband over power lines causes interference, claim US radio hams

American ham radio operators and at least one federal agency contend that broadband over power lines interferes with their radio...

American ham radio operators and at least one federal agency contend that broadband over power lines interferes with their radio signals and, if the radio operators have their way, the emerging technology might not get off the ground in the US.

The Amateur Radio Relay League (ARRL), a national ham radio association, and the Federal Emergency Management Agency are among the organisations that have raised concerns with the US Federal Communications Commission (FCC) over possible short-wave 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 cheaper 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 the power lines are already there.

The two sides are miles apart on the interference issue, which the FCC is examining in a request for public comments, which has been taking place 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 insist that they cannot 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.

Most BPL suppliers 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 suppliers are experimenting with devices that use microwave signals, and the ARRL says those devices would not interfere with ham radios.

But Current Technologies, which offers BPL service in the Cincinnati and Rockville, Maryland, areas, cannot 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 ARRL's policy to oppose any new technology that causes emissions, whether they be harmful or not." ARRL does maintain a web page, at,  listing 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, because the FCC could immediately shut them down if they did, Birnbaum added. 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 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. In December, the Federal Emergency Management Agency (FEMA) filed comments saying BPL could "severely impair FEMA's mission-essential HF (high frequency) radio operations".

The National Telecommunications and Information Administration at the US Department of Commerce is conducting its own study, and phase one 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.

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 has 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."

Grant Gross writes for IDG News Service

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