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 Previous: ARRL VEC Announces Vanity Call Sign License Renewal Program |  Next: The K7RA Solar Update |
NEWINGTON, CT, Apr 12, 2006--Interference persists on Amateur Radio frequencies from the Manassas, Virginia, BPL system, 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 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, although he allowed that the noise he heard April 11 while mobiling through Manassas was not as loud as it's been in the past. "Some days it will blow your ears off, other days not," he explained. "It varies. That's what's so aggravating about it." Agnew also took umbrage at COMTek's suggestion that he wouldn't be able to distinguish BPL interference from other types of interference.
The BPL signal can be heard along "miles of road" on 40, 20, 17 and 15 meters, one Manassas amateur reported. |
The Manassas BPL system uses Main.net equipment operating between on frequencies between 4 MHz and 30 MHz, according to the BPL database. |
The Manassas BPL system operates over both overhead and underground utility wiring. |
Another Manassas amateur, George Tarnovsky, K4GVT, who's also complained to the FCC of BPL interference, echoed Agnew's report. "Yes, of course it is," Tarnovsky responded when asked if the BPL interference was still audible this week. He told the ARRL the BPL signal can be heard along "miles of road" on 40 meters as well as 20, 17 and 15 meters. "It's everywhere," Tarnovsky said, adding that the interference level varies based on how heavily the system's approximately 900 customers are using the system.
The city and COMTek "have done little or nothing to work things out," Tarnovsky said. Meetings between the Amateur Radio community and COMTek and Manassas broke off several months ago. The FCC asked Tarnovsky and several other Manassas radio amateurs last month to provide additional information on their longstanding interference complaints. Tarnovsky said FCC Spectrum Enforcement Division Chief Joseph P. Casey rejected his first re-filing, telling him it wasn't in the format the FCC wanted. His subsequent complaint was accepted, he said.
In its April 6 filing with the FCC, COMTek said it takes interference complaints seriously. At the same time, the company--which runs the BPL system on behalf of Manassas over its city-owned power grid--said it's conducting "an ongoing investigation" to determine whether the "alleged interference" is coming from its BPL system. The Manassas system uses Main.net equipment and operates on frequencies between 4 MHz and 30 MHz, according to the BPL database.
On March 7, Casey called on the city and COMTek to follow up on Agnew's January 19 complaint citing harmful BPL interference along Virginia Business Route 234. The Commission directed the city to conduct measurements to ensure its system complies with FCC Part 15 rules. The Commission also instructed the city 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, where BPL equipment operates on overhead power lines. Product Safety Engineering qualified 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.
The tests appear to have been carried out and the report compiled just days before COMTek submitted the findings to the FCC. Conceding that the engineering firm's report was just an interim report and "not fully compliant with the FCC's new measurement guidelines," COMTek told the FCC it would provide 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 the hours of peak usage of the system by BPL customers," 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 that while Product Safety Engineering's report falls short of what is required to demonstrate system compliance, it "cannot even pretend" to address Agnew's interference complaint. "As a measure of the interference to radio communication emanating from the Manassas BPL system, the test results are meaningless," he asserted. "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."
The engineering firm used a spectrum analyzer and a loop antenna to conduct its series of measurements. Sumner and ARRL Laboratory Manager Ed Hare, W1RFI, maintain that a communications receiver coupled to an antenna typically used for radio communication would be sufficient to show the presence of the ongoing harmful interference.
"Interference and ambient noise levels cannot be measured with spectrum analyzers having 10 dB less sensitivity than a communications receiver and passive loop antennas that have -50 dBi of gain on 40 meters," Hare said. He notes the engineering report only covers one amateur band.
Hare charges COMTek with using public relations hoopla to gloss over its system's shortcoming. "They are trying to fix interference problems with press releases," he said. In the April 7 news release COMTek Vice President Walt Adams called the Manassas BPL system "a real success story" and said its testing showed "an almost identical" level of interference whether or not the system was in operation.
ARRL's technical analysis of the testing indicates COMTek cannot show that it can 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.
"I have confidence in technical approaches to problem solving," Hare concluded. "I don't see much of that here."
COMTek told the FCC that it plans to replace the existing BPL equipment along Route 234 in Manassas with Main.net "second-generation" equipment by this July. All overhead BPL equipment in the city will be replaced by this November, the company said.
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