 A map purporting to show US BPL deployments by utilities. Red dots indicate "commercial" deployments, while blue dots represent BPL field trials. The map, which UPLC included in a recent FCC filing, includes some systems scheduled to be phased out and fails to include others known to be in operation. [UPLC Graphic] |
NEWINGTON, CT, Sep 29, 2004--The United Power Line Council's (UPLC) broadband over power line (BPL) conference earlier this month in Arlington, Virginia, offered additional insights into BPL industry attitudes. The gathering September 12-15 featured speakers excited about BPL's future as well as those dismissive of Amateur Radio's interference concerns. Matt Oja of Progress Energy Corp (PEC), alluded to Amateur Radio interference complaints stemming from his company's BPL field trial in the Raleigh, North Carolina, area. Oja told the conference that that while the utility worked with local amateurs to successfully quell interference, the amateurs kept raising the bar until Progress had to put its foot down. Even after an FCC study in response to an Amateur Radio complaint essentially gave the system a clean bill of health, Oja said, the amateurs still were unhappy.
"We are not making further efforts because we are compliant with the Part 15 rules, and the FCC has given us a clean bill of health," Oja told the conference. He suggested amateurs would never be happy about BPL and advised utilities to simply move forward with their BPL programs.
Responding to Oja's comments as reported in the newsletter BPL Today, one of the amateurs directly involved in the Progress Energy BPL field trials, Gary Pearce, KN4AQ, offered a somewhat different version of events. "The only bar Progress Energy and Amperion need to meet is the one set by Part 15," Pearce said. "No harmful interference to licensed services." Amperion is PEC's BPL partner.
Pearce says that while amateurs appreciated Progress Energy's willingness to cooperate in addressing interference, strong BPL signals at the outset covered "substantial portions of the high-frequency radio spectrum, including several ham bands." Amperion ultimately was only partially successful in "notching" the ham bands out of its BPL system, Pearce noted, adding that interfering signals remained on amateur frequencies even after Progress announced it was ending its BPL field trial.
"And that's why 'The radio folks were still unhappy, and
that's not going to change,'" Pearce said, paraphrasing the BPL Today
article. "They've given us no confidence in their ability to get it right in
any reasonable time frame."
 An Amperion BPL extractor in the Cedar Rapids, Iowa, field trial, which shut down earlier this year. [Alan Erickson, WB0OAV, Photo] |
In another presentation, Amperion Marketing Vice President Jeff Tolnar declared that "all ARRL complaints have been mitigated and/or found to be invalid." In addition to the North Carolina BPL field trial, Amperion was Alliant Energy's partner in a Cedar Rapids, Iowa, BPL site which was shut down after the Amperion and Alliant were unable to satisfactorily resolve an Amateur Radio interference complaint ARRL had filed. Alliant Energy's BPL Project Leader Dan Hinz told the League that the ARRL complaint "certainly was a factor" in the utility's decision to pull the plug prematurely but "not the overriding factor."
Another conference speaker was John Hewa of the City of Manassas, Virginia, which has been operating a BPL field trial over its city-owned electric utility's lines. He asserted that hams in Manassas had filed no valid complaints and were pleased with the system's "proactive static notching" to avoid interference to ham bands.
The FCC so far has failed to respond to interference complaints from the Manassas-based Ole Virginia Hams Amateur Radio Club (OVH), however. Metavox Inc, ARRL's engineering consultants, determined that radiated emissions at the Manassas site exceed the Part 15 limits across the range 3.5 to 14 MHz. Manassas this past summer replaced its original BPL franchise holder, Prospect Street Broadband, with ComTek.
Several BPL equipment vendors also made presentations. Current Technologies told conference
attendees that they need to "address interference head on with data and facts."
Current President Tom Willie told the conference that Current's BPL system uses
a different part of the radio spectrum. The company has partnered with Cinergy
Corp in the most ambitious BPL rollout to date--in the Cincinnati area. Willie
said there have been no interference complaints so far.
 In the early stages of its BPL field trial near Raleigh, North Carolina, Progress Energy Corp worked with local amateurs to measure and mitigate interference on ham frequencies. The cooperative relationship fell apart after repeated interference complaints--more than a dozen in all--from area amateurs. [Gary Pearce, KN4AQ, Photo] |
ARRL Ohio Section Manger Joe Phillips, K8QOE, says there have been "some reports" of BPL interference but no formal complaints. "Cinergy has not established much of a BPL footprint yet," Phillips explained. A BPL task force is doing preliminary work in two neighborhoods where Cinergy has begun its BPL rollout.
A representative of PPL Telecom--a Pennsylvania utility running four BPL trials near Allentown--talked about the four RFI complaints it has received. All came from hams living within 500 feet of BPL devices.
PPL claims to have successfully resolved the complaints through frequency shifting, narrower bands, power reduction, and notching, which, while admittedly not perfect, provided 13 to 20 dB of attenuation. Several known hams in the area are not complaining, so "everything must be okay," a PPL representative said. PPL added that some hams told the utility they received less power line noise after BPL deployment, due to efforts to clean up noise sources.
ARRL Laboratory Manager Ed Hare, W1RFI, recently revisited the Hanover Township area and found moderate to strong BPL signals on amateur frequencies over a wide geographical area, however. He also found that absolutely nothing has been done to mitigate the strong interference levels in nearby Emmaus.
 Metavox Inc conducted BPL electromagnetic emission tests on behalf of ARRL at BPL field trials in Emmaus (above) and Whitehall, Pennsylvania, as well as in Manassas, Virginia. [Metavox Inc Photo] |
Bruce Franca of the FCC's Office of Engineering and Technology (OET) offered a BPL regulatory update. Standing in for his boss, OET Chief Ed Thomas, Franca noted the FCC has conducted a fair number of measurements and has found that BPL meets Part 15 emission limits and that notching was "highly effective." No BPL interference complaints above 30 MHz have been received, Franca told the conference, adding that there are "not a lot of licensed users below 30 MHz." He also said manufacturers and BPL operators have been working with licensed users. The FCC's draft BPL Report and Order in ET Docket 04-37 is expected to come before the FCC at its October 14 meeting.
 Point source vs line source: A graph showing BPL interference monitored on 14.588 MHz from the system in Briarcliff Manor, New York. The BPL signal was audible at the start and end of the runs, with strong levels observed in between. The strong interference level along the length of the runs clearly shows the overhead power line acting much more like a line-source radiator than a point-source radiator. [ARRL Graphic] |
For its part, the UPLC reiterated many of the statements it already had made in its reply comments on the FCC's February 2004 Notice of Proposed Rule Making. The UPLC stressed that BPL "is not a huge antenna but is really just a point source." Existing emissions limits should stand, the UPLC contended, and the risk of RF interference from BPL is low.
Tom Sullivan of the National Telecommunications and Information
Agency (NTIA) said his agency has an interest
in BPL issues because the federal government is a "heavy user" of the spectrum
below 30 MHz. The NTIA administers spectrum for federal government users. While
the NTIA has said BPL poses a genuine risk of RF interference, Sullivan
indicated the agency is less concerned with localized interference to "just a
few hams" than it is with the prospect of interference to government HF radars.
Sullivan stated that the NTIA is fully behind BPL and that his agency has sent
a letter of recommendation to the FCC. That letter has not yet been made
public. --Anthony E. "Goody"
Good, K3NG
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