When it was writing the BPL rules, the FCC under then-Chairman Michael Powell did not disclose these staff studies. It was only in response to an ARRL Freedom of Information Act (FOIA) request, and then only after the rules had been rushed to adoption, that the Commission deigned to draw back the curtain to provide selective glimpses of its staff’s work. The documents were redacted, or selectively edited to withhold certain material from public view (the time for public comment having already passed). From their placement within the remaining material, there was reason to suspect that the basis for the deletions was simply that they contradicted the Commission’s conclusions that BPL posed but a “small and manageable degree of interference risk” to licensed radio users.

When the ARRL finally had the opportunity to address the redacted studies in our 2005 petition for reconsideration, the Commission’s response was self-contradictory. The FCC conceded that it had “relied…on its own internally conducted studies as described in the FOIA response to ARRL” yet it claimed that “the redacted portions of the FOIA’s content referred to internal communications that were not relied upon in the decision making process.”

Under Kevin Martin, Powell’s successor as Chairman, the FCC managed to make matters worse when it took up the reconsideration petitions the following year. The Commission adopted a new rule exempting BPL operators from having to do anything more to address interference to HF mobile stations than to implement a 20 dB notch on the mobile frequency.

Having exhausted our administrative remedies, the ARRL went to court. Our efforts finally were rewarded on April 25, 2008 when the US Court of Appeals for the District of Columbia Circuit found that FCC prejudice had tainted the rulemaking process. Observing that there is no precedent allowing an agency to “cherry-pick” a study on which it has chosen to rely in part, the Court ordered the Commission, on remand, to release the unredacted studies and provide a reasonable opportunity for public comment.

The Court of Appeals also found that the FCC had mishandled the choice of an extrapolation factor. The factor the Commission chose, 40 dB per decade, is contradicted by several published studies that support a lower figure. In other words, as one moves away from a power line the FCC rules assume that BPL interference drops off more quickly than it does in reality. The Court ordered the FCC either to “provide a reasoned justification for retaining an extrapolation factor of 40 dB per decade…or adopt another factor and provide a reasoned explanation for it.”

Incredibly, 11 months later the FCC had failed to take any action whatsoever. Armed with the new Administration’s policy of openness on FOIA requests, the ARRL submitted another one — and this time it was granted. While we are still trying to determine whether all of the previously redacted material has been released, we have seen enough to confirm our suspicions.

One part of an FCC staff report that the Commission chose not to rely upon turns out to be a summary of findings of its sister agency, the National Telecommunications and Information Administration (NTIA). According to the summary, the NTIA predicted approximately 60% probability that a mobile station 15 meters from a BPL-carrying power line would experience a 30 dB increase in noise floor at 15 and 25 MHz. The probability of a 20 dB increase was well over 90% in both cases. The summary also noted that the NTIA’s predictions were based on a higher environmental noise level than is experienced in practice; in other words, the interference in reality would be greater than predicted.

Repeated references to the FCC staff’s finding that BPL is not a point source emitter were redacted. It is significant that the Commission chose to withhold these references because Part 15 emission limits originally were developed for point-source emitters. They are inherently insufficient to safeguard licensed services against interference that radiates from a line rather than from a point source.

We were especially curious about the redacted contents of a page titled “HF Issues and Options.” From the unredacted version we have learned that FCC staff offered two options, either one of which would have constructively addressed the interference issue. The first was to ban BPL from using frequencies below 30 MHz on overhead power lines. The second was to impose a 5 dB height correction factor and an extrapolation factor of 20 dB per decade.

The most outrageous redaction we have found so far is a single parenthetical statement, the deletion of which completely reversed the meaning of the sentence. The FCC let stand a suggestion by the Chief Technology Officer of a BPL company, but redacted its own staff’s observation that his suggestion was invalid!

Want to compare redacted and unredacted pages for yourself? We’ve put up a link accessible via the “BPL” button on the ARRL home page.

To summarize, before adopting its flawed BPL rules the FCC knew that a 20 dB notch is insufficient to protect mobiles from interference. The FCC knew that BPL is not a point source emitter. The FCC knew that 40 dB per decade is not the right extrapolation factor, and that banning HF BPL on overhead power lines is the best option to protect the viability of HF communications. The Commission knew this because its own technical staff said so.

And now we know that they knew. Here’s what we don’t know: Now that Powell and Martin are gone, will the new leadership at the FCC fix this?

David Sumner, K1ZZ
ARRL Chief Executive Officer