ARRL Seeks Clarification of FCC Response to BPL Interference Complaint:

The ARRL wants the FCC to further explain its recent response to a North Carolina amateur's complaint of BPL interference. FCC Office of Engineering and Technology (OET) Deputy Chief Bruce A. Franca replied July 22 to an April 27 BPL interference complaint from Thomas A. Brown, N4TAB, of Wake Forest. Brown had complained of BPL interference to his amateur HF mobile station emanating from a Progress Energy Corp (PEC) BPL field trial in the Raleigh area. In his letter, copied to ARRL, Franca said an on-site investigation had concluded that PEC's BPL trial "is in compliance" with FCC rules and that the company's ham band notching efforts "are effective" to avoid the potential for harmful interference. ARRL CEO David Sumner, K1ZZ, however, cited evidence to the contrary.

"It is not at all clear that the tests and measurements taken by the FCC . . . established the absence of harmful interference to licensed stations," Sumner responded July 22. He said the League would like the OET to make its test report available to the general public or at least to the League for technical review and comment. The ARRL also wants to know what steps PEC took between April 27 and June 28--when the FCC began its testing--to address interference complaints from Brown and several other radio amateurs.

The FCC defines as "harmful" any interference that "seriously degrades, obstructs or repeatedly interrupts a radiocommunication service operating in accordance with the Radio Regulations."

According to Franca, FCC personnel "undertook extensive testing and measurements" of the PEC BPL system between June 28 and July 2. The complainant--Brown--says the FCC delegation never contacted him while it was in North Carolina. Franca says FCC measurements indicated notch depths averaging 24 dB below Part 15 emission limits, which he characterized as "sufficient to eliminate any signals that would be deemed capable of causing harmful interference, including interference to amateur operations."

Franca maintained that "in no instances" were signal levels high enough to "cause serious degradation, obstruction, or repeated interruption" of amateur mobile or fixed communications. He conceded, however, that notching on 10 meters was somewhat less effective at the low end of the band and said the FCC would instruct PEC and its partner, Amperion, to widen its notch there.

Sumner noted that the Part 15 device operators "must eliminate all harmful interference, and therefore in some cases must achieve more--in certain cases, considerably more--than a 24 dB reduction in order to be in compliance." He also cited recent reports from amateurs in the area indicating that strong BPL interference continues in parts of the PEC trial zone.

Sumner told Franca that amateurs in the Raleigh area on July 17 and again July 22 monitored a BPL signal "at full strength and causing harmful interference" from 14.290 to 14.350 MHz. "Harmful interference" also was reported in the first 100 kHz of 15 meters as well as on the WWV/WWVH frequencies of 15.000 and 20.000 MHz and on several international broadcasting bands.

"Even in the notched bands," Sumner said, "the interference was still evident on ordinary amateur equipment." He said it's clear to ARRL that the system's Holland Church Road site--where the most recent amateur measurements were taken--is in violation of Part 15.

For his part, Brown--an engineer with considerable RF experience--said he was glad the FCC finally took some action but found some of Franca's assertions "very troubling." He told ARRL that his 14-page complaint cited interference "sufficient to mask a weak signal," although it did not register on his S meter. An active Amateur Radio Emergency Service District Emergency Coordinator, Brown said it's not unusual to have to copy similarly weak signals during an HF emergency net.

"I suspect the principal reason for their coming down here was to say they've actually done something," Brown commented. He also worried that the FCC was attempting to define a standard of "acceptable interference" within the framework of what constitutes "harmful interference."

"If it interferes, it interferes," he maintained.

Sumner also requested that the FCC clarify some additional aspects of its North Carolina testing and measurement activities.

"Until these points can be clarified," he concluded, "we trust that the Commission will not permit its conclusion to be erroneously represented as having given the Progress Energy trials a 'clean bill of health.'"

Source:

The ARRL Letter Vol. 23, No. 30 July 30, 2004

Member Comments: