ARRL Documents Flaws in Manassas BPL Interference Report:

In response to a report from BPL operator COMTek that claims its BPL system in Manassas, Virginia cannot be shown to be the cause of ongoing interference complaints by local amateurs, the ARRL has documented the report's shortcomings and again has demanded that the FCC shut down the system until the interference problems are solved.

In an April 14, 2006 letter to two FCC officials, ARRL General Counsel Christopher D. Imlay, W3KD, concluded: "In light of the record of long-standing interference to licensed stations in Manassas, and the failure of COMTek and the City of Manassas to comply with Section 15.615(d), the Commission should require that the BPL system be shut down immediately, and not resume its operation until the facility is shown to be in full compliance with Commission rules regarding radiated emissions and the non-interference requirement of Section 15.5 of the Commission's rules."

The 10 page letter, addressed to Joseph Casey, Chief, Spectrum Enforcement Division, and Katherine Power, of the Spectrum Enforcement Division, sets forth in detail the "tortured history of interference complaints involving the BPL system." COMTek's report was submitted to the FCC in response to a letter from Casey to the City of Manassas and COMTek requiring a "report of system compliance and your report of actions taken to address the alleged harmful interference." The report states, "COMTek believes that the current configuration of the Manassas BPL System is not the source of interference to amateur radio licensees." The ARRL response, citing ongoing interference complaints, called the study "fatally and obviously flawed."

Appended to the ARRL letter to the FCC was a detailed analysis of the technical study prepared by ARRL Lab Manager Ed Hare, W1RFI. The analysis concluded: "…the testing that was performed in no way is sufficient to reach any general conclusions about emissions levels." The analysis goes on to criticize the methodology and conclusions of the tests, which were performed by Product Safety Engineering, Inc. Hare's analysis found a number of deficiencies in the PSE report, including:
The testing was not done in accordance with the FCC's recommended test guidelines;
The test equipment used -- a spectrum analyzer and a passive loop antenna -- was not sufficient to measure notch depth nor to measure the ambient noise levels;
PSE tested only one amateur band at a single location, which was insufficient to establish compliance or non-interference; and
The testing does not follow good engineering practice and is not sufficient to have met the requirements set forth by the FCC for this testing.

The ARRL letter to the FCC concluded:

"…The Manassas and COMTek non-responses to the Commission's directive; their vague assurances to work with the Amateur Radio operators in the future; and their stonewalling on the cause of the harmful interference should not be tolerated by the Enforcement Bureau and will not be further tolerated by the Amateur Radio community in Manassas, or by ARRL."

Source:

The ARRL Letter Vol. 25, No. 16 April 21, 2006

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