Rep Greg Walden, W7EQI (R-OR).
NEWINGTON, CT, May 20, 2004--A BPL industry witness told a House Subcommittee on Telecommunications and the Internet hearing May 19 that the extensive National Telecommunications and Information Administration (NTIA) broadband over power line interference study draws "generalized conclusions," some of which are inaccurate. Jay Birnbaum, vice president and general counsel of BPL provider Current Communications Group LLC was among those answering lawmakers' questions during the hearing, "Competition in the Communications Marketplace: How Convergence Is Blurring the Lines Between Voice, Video, and Data Services." ARRL CEO David Sumner said he found it "interesting" that a BPL spokesperson would try to downplay the significance of the NTIA's findings.
"Clearly, the report has the BPL industry worried--as well it should," Sumner said. "Anyone who gets past the introduction and actually reads the body of the NTIA study can only conclude that NTIA's findings are devastating to the case for BPL."
Among other observations, the NTIA acknowledged that BPL signals "unintentionally radiate" from power lines, but said there's "substantial disagreement as to the strength of the emissions and their potential for causing interference to licensed radio systems."
Rep Greg Walden, W7EQI (R-OR). |
The subcommittee members questioning Birnbaum included Oregon Republican Greg Walden, W7EQI, one of two amateur licensees in the US House. Walden asked Birnbaum to address the BPL interference issues that the NTIA report and the amateur community have raised.
Birnbaum responded that he thinks interference concerns about BPL are unfounded and that the FCC agrees. BPL emissions from power lines, he asserted, are at very low levels and dissipate very quickly with distance. Current Technologies is field testing a BPL system in Potomac, Maryland, and has a 50-50 partnership with Cinergy to deploy a full-blown BPL system in the Cincinnati area. The Maryland system employs the HomePlug Alliance standard, which notches all HF amateur bands except 60 meters. It uses orthogonal frequency division multiplexing (OFDM) technology.
The ARRL documented a visit to the Potomac test area on its Web site. The Potomac site is identified as "Trial Area #1" under "Video showing results of ARRL testing in MD, VA, PA and NY." BPL interference heard outside amateur bands at the Potomac site sounds like severe, irregular pulse-type noise.
Walden also questioned Birnbaum regarding how far away BPL interference might be detected. Birnbaum indicated that while there's disagreement on the issue, it's "literally undetectable" tens of meters away. He said FCC and NTIA engineers have found signal levels too low to measure. He also told Walden that a lot of complaints about BPL are based on outdated data and technology. Walden said he just wants the interference addressed technically--"especially driving under power lines."
The NTIA, which conducted measurements at three different
BPL field trial sites, said that while radiated power "decreased with
increasing distance," the decay was not always predictable. At one measurement
location with a number of BPL devices, the NTIA said, "appreciable BPL signal
levels (ie, at least 5 dB higher than ambient noise) were observed beyond 500
meters from the nearest BPL-energized power lines."
 A BPL "extractor" on a power line in the Raleigh, North Carolina, area, where Progress Energy and Amperion have partnered to field test a BPL system. [Gary Pearce, KN4AQ, Photo] |
The NTIA study further calculated that interference "is likely" to mobile stations in areas extending to 30 meters and to fixed stations in areas extending to 55 meters from a single BPL device and the power lines to which it's connected. Interference to systems with "low to moderate desired signal levels," such as those common in ham radio, is likely within areas extending to 75 meters for mobiles and 460 meters for fixed stations, the NTIA study said.
Responding to a question from New Hampshire Republican Charles Bass, Birnbaum said the BPL industry would be pleased if Congress could provide tax or financial incentives, especially for improving the power grid. He said utilities have not explored the broadband market in the past because some companies had bad experiences and the technology was not feasible five years ago.
Birnbaum suggested, too, that while utilities are slow to
act, they will begin to deploy BPL systems over the next year or two. The
biggest issue, he said, is the incentive for utilities to invest in broadband
technology.
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