BPL Problems Unresolved

Andre Kesteloot andre.kesteloot at verizon.net
Fri Apr 14 08:06:02 CDT 2006


Interference from the Manassas, Virginia, BPL system persists on ham radio
frequencies, radio amateurs there say. Their reports fly in the face of an
April 7 news release from system operator COMTek that a recent engineering
survey found "no interference unique to BPL" in the amateur bands. On April
6, COMTek filed a report
<http://www.arrl.org/tis/info/HTML/plc/files/COMTek.pdf> with the FCC in
response to an earlier interference complaint from Dwight Agnew, AI4II.
COMTek said it does not believe the Manassas BPL system caused the
interference Agnew and other Manassas ham radio operators have heard. Agnew
told the ARRL this week that the BPL interference continues.

"Yes, it's still there," Agnew said. "Some days it will blow your ears off,
other days not," he explained. "It varies. That's what's so aggravating
about it."

Another Manassas amateur, George Tarnovsky, K4GVT, who's also complained to
the FCC of BPL interference, echoed Agnew's report. He told the ARRL the BPL
signal still can be heard along "miles of road" on 40 meters as well as 20,
17 and 15 meters. "It's everywhere," Tarnovsky said. He points out the
interference level varies based on how heavily the system's approximately
900 customers are using the system.

In its April 6 filing with the FCC, COMTek--which operates the BPL system
for the city--said it takes interference complaints seriously and is
conducting "an ongoing investigation" to determine whether the "alleged
interference" is coming from its equipment. The Manassas system uses
Main.net equipment on frequencies between 4 MHz and 30 MHz, according to the
BPL database.

On March 7, FCC Spectrum Enforcement Division Chief Joseph P. Casey
requested the city and COMTek to follow up on Agnew's January 19 complaint
citing harmful BPL interference along Virginia Business Route 234. The
Commission told the city to test its system to be sure it complies with FCC
Part 15 rules and to "resolve any continuing harmful interference."

COMTek's FCC filing included a test report by Product Safety Engineering Inc
of Dade City, Florida, outlining BPL system measurements made on 40 meters
at one location on Route 234. Product Safety Engineering tempered its
report, however, by saying its measurements "were not intended to qualify
the system or BPL equipment with respect to compliance with the FCC rules."
They were intended to "assist the client in gaining an understanding of the
interference potential" of the BPL equipment at "a specific location," the
engineering firm said. 

Conceding that the engineering firm's report was interim and "not fully
compliant with the FCC's new measurement guidelines," COMTek told the FCC it
would supply a complete survey by April 14.

The ARRL already has called on the FCC to shut down the Manassas system
until it complies with FCC Part 15 rules. ARRL CEO David Sumner, K1ZZ, says
COMTek's April 6 FCC filing failed to provide what Casey had requested last
month. That included making measurements at multiple locations Agnew
described in his January complaint. The engineering report also gives no
indication that the tests were performed during peak system usage hours, as
the FCC had required.

"No explanation was provided as to why COMTek was unable to comply with the
FCC requirement to resolve the interference complaint and to report within
30 days," Sumner said. "Yet on April 7, COMTek issued a news release that
claimed 'rigorous FCC-mandated testing' had been completed. In fact, the
testing completed as of that date failed to comply with FCC requirements, as
acknowledged by COMTek itself."

Sumner said "the test results are meaningless" as a measure of the radio
interference emanating from the Manassas BPL system. "Using the test
equipment described in the test report to check for radio interference is
like using an oven thermometer to check for a fever."

Sumner reiterated the League's request that the FCC order the Manassas BPL
system disabled "until its operation is able to comply fully with the FCC
rules and instructions."

ARRL Laboratory Manager Ed Hare, W1RFI, charged COMTek with "trying to fix
interference problems with press releases." ARRL's technical analysis of the
testing indicates COMTek cannot show that it's able to meet FCC-required
emission limits, Hare said, and doesn't even demonstrate that its system is
not causing harmful interference.

Hare said BPL manufacturers and providers whose technology can operate
compatibly with Amateur Radio have been working closely with the ARRL and
local amateurs. "Those that cannot are taking preliminary test results and
turning them into 'everything-is-wonderful now' news releases," he said.
"From a technical point of view, that moves us further from solutions, not
toward them."

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