The U.S. Court of Appeals for the D.C. Circuit, responding to an appeal brought by the Amateur Radio Relay League (ARRL),  today sent parts of the Broadband-over-Power-Line (BPL) Rules back to the FCC for a second look.  The challenged rules remain in force in the meantime.

The court was unhappy with two aspects of the FCC’s decision-making process.

First:  Among the many technical studies that played a part in the proceeding were five performed by the FCC itself.  The FCC placed these in the public docket, but redacted some passages that it said were "preliminary or partial results or staff opinions."  It claimed no reliance on those passages in reaching its conclusions.  But the court, having seen the redacted portions, suspected they might contain evidence that could call the rules into question.  For that reason it ordered the FCC to publish the material and to receive public comment on it.

Second, the FCC had carried over from earlier rules an "extrapolation factor" of 40 dB/decade at frequencies below 30 MHz.  (The number is used for equating measurements taken at various distances.)  The court agreed with ARRL that the mathematical models used to justify the value relied on measurements from other technologies, and further, that the FCC had failed to explain why it disregarded empirical studies in the record showing that 40 dB/decade was inappropriate.  The FCC must now either justify or change the extrapolation factor.

On two other points, the court sided with the FCC.  ARRL had argued that the FCC inadequately explained why it allowed BPL to be deployed on an unlicensed basis, notwithstanding a supposed admission that BPL could cause harmful interference to licensed mobile amateur users.  The court detected no such admission; to the contrary, it cited FCC findings that such interference would not occur.  And the court held that the FCC had adequately explained its decision not to confine BPL to 30-50 MHz, where the amateurs have no operations.

The next step in the process will be a request for comments from the FCC.  Considering that the original BPL proceeding drew 8,000 submissions, many of them strongly worded, the FCC is bracing itself for this new round, which is likely to be at least as contentious.