==>PUT BPL PROCEEDING ON ICE FOR FURTHER INTERFERENCE EVALUATION, ARRL
The ARRL has asked the FCC to put its BPL proceeding on hold to allow more
thorough research of BPL's interference potential to licensed radio
services. Among other things, the ARRL wants to more closely review the
lengthy National Telecommunications and Information Administration (NTIA)
Part 1 BPL study released April 27. In comments filed May 3 in response to
the FCC's February 23 BPL Notice of Proposed Rule Making (NPRM) in ET
Docket 03-47, the League also called on the FCC to apply "considerably
more conservative radiated emission limits" to BPL than those applying to
"normal" Part 15 devices. Five technical exhibits, including an
ARRL-commissioned independent study at BPL trial areas and additional
research, accompanied the League's comments.
"The Commission cannot be in such a hurry to deploy BPL . . . that it must
sweep under the rug the mounting evidence that BPL is a significant source
of interference to licensed radio services and is not in the public
interest," the ARRL declared.
The League also took the FCC to task for its willingness to balance BPL's
presumed benefits against the potential of harmful interference. "The
principal obligation of the Commission in permitting unlicensed devices or
systems is to establish a radiated emission level that is sufficiently low
that by their operation they will predictably not interfere with licensed
radio services," the ARRL emphasized.
The ARRL told the FCC that applying existing radiated emission limits to
so-called "access BPL" systems is inappropriate. "Those levels are far too
high and were designed to address the interference of point-source
radiators," the League said. "It is obvious that access BPL systems are
distributive, line-source radiators" and the FCC should apply a limit low
enough to prevent interference to mobile stations that might operate in
BPL-served neighborhoods. The ARRL suggested that 0 dBuV/m at the antenna
measured at 10 meters (approximately 33 feet) from the power line would be
an "acceptable" radiated emission level.
The League further proposed amending Part 15 rules (§15.109) to require
BPL systems to incorporate adaptive interference resolution techniques
adequate to cause them to cease operation within an hour following a
report of harmful interference to an FCC licensee's station. The BPL
system then couldn't resume operation within one kilometer (approximately
0.62 mile) of the complainant's station "unless and until the harmful
interference is resolved." The ARRL also would require BPL systems to
supply detailed information on their systems to a public Web-based
The FCC's NPRM offers no support for its conclusion that interference to
licensed services would be minimal, the ARRL said, and it noted that
amateur licensees have filed more than two dozen BPL interference
complaints with the FCC.
"Some of these interference problems have persisted, notwithstanding the
good faith efforts of some BPL service providers to resolve the problems,"
the ARRL noted. "In other cases, the complaints are simply ignored. None
has been adjudicated by the Commission, as far as the ARRL can tell."
Instead, the League said, amateurs' BPL complaints "remain under wraps" in
the Office of Engineering and Technology instead of being handled by the
FCC's Enforcement Bureau, which typically deals with power line noise
complaints from radio amateurs.
"Mere mitigation" of interference is not sufficient, the ARRL said. "It is
the absolute obligation of the operator of a Part 15 device or system to
prevent interference." The League pointed out that the FCC's NPRM does not
require interference resolution. "The interference to fixed amateur
stations located in residences in normal geographic proximity to overhead
power lines will be devastating and will preclude Amateur Radio
communications," the League predicted. It called the FCC's proposed
mitigation techniques "too little, too late to avoid widespread
Referring to its main BPL study, the League said measurements at one site
within a BPL test system in Emmaus, Pennsylvania, "exceeded FCC Part 15
limits by up to 20 dB or more." At another test site in Whitehall,
Pennsylvania, using another technology, the study concluded that the BPL
signals--while apparently within Part 15 limits--"would have interfered
seriously with reception of Amateur Radio signals."
"This proceeding should be placed on hold for a year in order to work out
appropriate interference avoidance and resolution standards," the League
The League was among more than 1000 individuals and entities commenting in
the proceeding by the May 3 deadline. Reply comments are due Tuesday, June
1. On the eve of the comment deadline, the FCC denied several
requests--including one from the ARRL--to extend the comment period.
The League's comments are posted on the ARRL Web site