Subject: [NEXTEL-1] Internet Access Over Power Lines Creates Radio Interference

From: [email-masked]
Date: Sun, 09 May 2004 09:11:51 -0400

Internet Access Over Power Lines Creates Radio Interference

Greg Flakus
Houston
08 May 2004, 13:37 UTC

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.

http://www.voanews.com/article.cfm?objectID=FBA95803-F602-4917-8A8BDA000DB17713

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