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Internet Access Over Power Lines Creates Radio Interference - 2004-05-08

The Federal Communications Commission is looking into complaints from amateur radio operators about the use of electrical power lines for providing broadband internet service, a concept known as BPL, for Broadband over Power Lines. Many power companies and some members of the commission see this as a promising technology that could be especially useful in getting such service to remote rural areas at a reasonable price. But the cost could be high in terms of radio interference.

The promise of Broadband over Power Lines is an effective and relatively inexpensive way of providing high-speed internet service to homes and businesses through the power lines that already exist.

Power lines can be viewed as large pipes bringing energy into an area where other lines branch off to buildings and houses. Not all the frequency range in the line - or space in the pipe - is used, thereby leaving open the possibility of sending signals back and forth over the line.

Matt Oja is Director of Emerging Technology for North Carolina-based Progress Energy, which has been trying BPL service in a limited area for about a year. He says his company is closely monitoring the system to see how well it works and what problems need to be addressed.

"Utilities today are trying to figure out if this is the type of thing we can deliver with the right partners in an effective and efficient manner," he said. "That is going to take some more checking out to make sure that we are able to do that."

But power lines can also be viewed as long antennas. The energy running through them transmits signals out around the lines. In cases where the signals interfere with other services that rely on the same frequencies there can be what the FCC terms harmful interference.

This is not permitted under the FCC rules, but Matt Oja says Progress Energy, working with a consultant company, has been able to identify such problems and solve them by notching, that is modifying the frequencies so as not to create interference.

"Given a situation where interference does occur to somebody who has a legitimate claim and has a legitimate interference concern and has experienced, quote-unquote, harmful interference, can this be mitigated around that particular frequency? That is what the company we have been working with here has been able to do, that is, notch out and get away from those bands when, indeed, that situation does occur," said Matt Oja.

But the success of this approach is questioned by amateur radio operators and others who rely on radio signals that could be interrupted by the power lines.

Tests of Broadband over Power Lines in Japan and Europe found interference that was deemed unacceptable. U.S. amateur radio operators say the measures employed by Progress Energy and other companies to mitigate interference have not been satisfactory because of signal noise produced by the transmitters that need to be placed, at intervals, along a power line to keep the signal flowing.

American Radio Relay League President Jim Haynie, speaking to VOA from his home in Dallas, Texas, says this presents a problem for amateur radio aficionados, police and emergency radios, and even short-wave receivers.

"If you can imagine having this in your power line, these little transmitters all up and down the power line and you try to listen to Voice of America or BBC or any of the other short-wave stations, you are going to hear that short-wave noise that is on the power line right by your house because it is going to be a whole lot stronger than the signal you are trying to listen to," he said.

Progress Energy and many other companies experimenting with BPL tout broadband access to remote neighborhoods and rural areas as one of the potential benefits of the technology. Progress Energy's Matt Oja says it might not be cost effective to put in a special line or cable to some remote areas, but power lines usually go to those places already and could be utilized to provide broadband service.

"This is one of the great opportunities that BPL does have is that it is possible to bring in a signal to a point, and carry it down a road and carry it into neighborhoods where the population cannot get access, where there are not enough homes or something to that effect," he said. "We think BPL might provide some real benefits out there."

But Mr. Haynie says he and other amateur radio operators see this is as a false promise because power companies would still have to invest in transmitters to boost signals to those remote areas, making it too expensive to be practical.

"Why don't they have DSL [Digital Subscriber Line] now? Why don't they have cable now? It is because it costs too much to serve a rural area," said Jim Haynie. "Ten, 20 people in a square mile and say three or four of them sign up for the service at $30 a month, it is not going to offset an investment of $10,000 or $20,000, $25,000 to bring it out there."

The dispute is not likely to disappear any time soon. FCC Chairman Michael Powell has called Broadband over Power Lines a "monumental breakthrough in technology." The commission has permitted further testing and development of the technology as long as there are appropriate measures to mitigate interference with radio signals.