FCC BPL Report and Order stresses interference avoidance, resolution

The FCC this week released the full BPL Report and Order (R&O) in ET Docket 04-37 that it adopted just two weeks ago. While extolling the purported benefits of broadband over power line technology, the 81-page document also declares the FCC's intention to protect licensed services
from harmful interference.

"We recognize that some radio operations in the bands being used for Access BPL, such as those of Amateur Radio licensees, may occur at distances sufficiently close to power lines as to make harmful interference a possibility," the FCC conceded in its R&O. "We believe that those situations can be addressed through interference avoidance techniques by the Access BPL provider such as frequency band selection,
notching, or judicious device placement."

Notches would have to be at least 20 dB below applicable Part 15 limits on HF, 10 dB below on VHF. The FCC called the ability to alter a system's operation to notch out transmissions on specific frequencies where interference is occurring "a necessary feature for resolving interference
without disrupting service to BPL subscribers."

In line with remarks made at the October 14 open meeting where the FCC adopted the R&O--then still in draft form--the FCC declined to reduce the Part 15 radiated emission limit for BPL systems. It maintained that emissions from BPL systems are very localized and at low enough levels to
generally preclude harmful interference.

The FCC said it had no evidence before it that BPL operation wouldsignificantly contribute to generally raising background noise levels. At the same time, it seemed to put some of the onus on Amateur Radio licensees to take steps to avoid power-line interference--and, by inference, BPL interference--in advance.

"In addition, because power lines inherently can radiate significant noise emissions as noted by NTIA and ARRL, good engineering practice is to locate sensitive receiver antennas as far as practicable from power lines," the FCC said.

In a footnote, the FCC took pains to advise ARRL that in cases where its members experience RF noise, "such noise can often be avoided by carefully locating their antennas; in many instances an antenna relocation of only a relatively short distance can resolve noise interference."

BPL operators would be required to avoid certain bands, such as those used for life and safety communications by aeronautical mobile or US Coast Guard stations. The FCC R&O makes clear, however, that similar rules will not apply to the Amateur Service.

"We similarly do not find that Amateur Radio frequencies warrant the special protection afforded frequencies reserved for international aeronautical and maritime safety operations," the Commission said. "While we recognize that amateurs may on occasion assist in providing emergency
communications," the FCC added, it described typical amateur operations as "routine communications and hobby activities."

Although some cases of harmful interference may be possible from BPL emissions at levels up to Part 15 limits, the FCC said, "we agree with NTIA [National Telecommunications and Information Administration] that the benefits of Access BPL service warrant acceptance of a small and manageable degree of interference risk." The Commission reiterated in the R&O its belief that BPL's public benefits "are sufficiently important and significant so as to outweigh the limited potential for increased harmful
interference that may arise."

Among other specific provisions, the FCC's new rules mandate certification of BPL equipment instead of the less-stringent verification, a public BPL database--something the BPL industry did not want--and mechanisms to deal swiftly with interference complaints. BPL systems will have to incorporate the ability to modify operation and performance "to mitigate or avoid potential harmful interference" and to deactivate problematic units, the R&O says.

Further, the new rules spell out the locations of "small geographic exclusion zones" as well as excluded bands or frequencies--concessions made primarily at the insistence of the NTIA, which administers radio spectrum for federal government users--and "coordination areas" where BPL
operators must "precoordinate" spectrum use. The rules also detail techniques to measure BPL emissions from system equipment and power lines.

The FCC said it expects "good faith" on both sides in the event of interference complaints. While the Commission said it expects BPL operators to take every interference complaint seriously and to diagnose the possible cause of interference quickly, it also suggested that complainants have responsibilities.

"At the same time, we expect the complainant to have first taken reasonable steps to confirm that interference, rather than a receiver system malfunction, is occurring and, to the extent practicable, to determine that the interference source is located outside the complainant's premises," the Commission said.

Shutting down a BPL system in response to a valid interference complaint "would be a last resort when all other efforts to satisfactorily reduce interference have failed," the FCC said.

League officials are studying the R&O and considering possible responses. The ARRL Executive Committee (EC) already has authorized filing a Petition for Reconsideration. The EC also authorized ARRL General Counsel Chris Imlay, W3KD, to "prepare to pursue other available remedies as to
procedural and substantive defects" in the BPL proceeding.

For more information on BPL, visit the "Broadband Over Power Line (BPL) and Amateur Radio" page on the ARRL Web site.

Source: ARRL Letter - courtesy of The American Radio Relay League

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