Access Broadband over Power line (BPL) places broadband data on existing electrical wiring—outdoor distribution and to the home—using radio frequencies ranging between 3 MHz and 80 MHz. These are the same frequencies used for shortwave radio broadcasting, amateur radio communications, and the low VHF TV band (channels 2-6). With the DTV transition complete and only about 40 full-power TV stations transmitting on these channels, BPL is unlikely to have a major impact on TV reception, although at short distances the Third harmonic of BPL signals might interfere with high-VHF (channels 7-13) reception. Viewers of low-power TV stations that moved to the low VHF channels left behind after full power stations' DTV transition are much more likely to have problems with BPL signals.
The American Radio Relay League (ARRL), representing Amateur Radio operators, has long criticized the FCC for rules that don't sufficiently protect ham radio operators and shortwave listeners from BPL interference and failing to enforce the BPL interference rules that do exist. The ARRL challenged the FCC rules in the United States Court of Appeals for the District of Columbia. As a result of this challenge, the Court required the FCC to: "1) make part of the rulemaking record unredacted versions of several staff technical studies which the Commission considered in promulgating the rules, 2) provide a reasonable opportunity for public comment on those studies, and 3) provide a reasoned explanation of its choice of the extrapolation factor for use in measuring radiated emissions from Access BPL systems." In response, the FCC issued a Request for Further Comment and Further Notice of Proposed Rulemaking (RFC/NPRM).
Monday the FCC issued the Second Report and Order (FCC 11-160). After this long proceeding, lasting over 7 years from the time the FCC adopted the Access BPL rules, the commission said, "In this Second Order, we complete our action addressing the court's concerns and our proposals in the RFC/FNPRM. We find that the information submitted in response to the RFC/FNPRM does not warrant any changes to the emissions standards or the extrapolation factor. We are, however, making several refinements to our Access BPL rules." See all filings in Docket 04-37.
The refinements include increasing the notch filtering capability for systems operating below 30 MHz from 20 dB to 25 dB; establishing a new alternative procedure for determining site-specific extrapolation factors; and adopting a definition for the "slant-range distance" used in the BPL measurement guidelines to further clarify its application. The Second Report and Order notes, "We find that the benefits of the above changes to the rules outweigh their regulatory costs...".
The Second Report and Order has more details on the modifications. Appendices C and D include rules changes and measurement guidelines, respectively. The concerns of the ARRL and its arguments are evaluated in detail and mostly dismissed in the 76 page Order and Appendices. As of Wednesday night, the ARRL had not posted the news or a response on its Regulatory and Advocacy web page.