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NEWINGTON, CT, Oct 18, 2005--Not all BPL systems are created equal. Some have far less potential to interfere with Amateur Radio than others. That's the rationale behind a petition the ARRL filed today, seeking to have the FCC modify the Part 15 BPL rules it adopted a year ago and sharply reduce the technology's potential to cause interference. In exchange, the League said it would withdraw its still-pending Petition for Reconsideration in the BPL proceeding, ET Docket 04-37. The ARRL says its suggested rule amendments--which take into consideration recent advancements in BPL technology--will "resolve unsettled but substantial interference issues" that affect Amateur Radio and other HF users.
"It is no longer the case that all BPL systems inherently radiate high levels of RF energy on amateur allocations on overhead medium-voltage power lines," the ARRL said. "Thus, not all BPL architectures have similar potential for harmful interference to the Amateur Radio Service (and to other licensed services). Some have inherently greater potential for interference, as currently configured, than others."
The problematic systems, the League said, are those that make use of the HF spectrum on unshielded overhead medium-voltage lines. ARRL further noted that BPL systems such as those using DS2 or Main.net technology that lack fixed, permanent notches in the ham bands have been among those involved in interference cases. "As detailed in ARRL's Petition for Reconsideration in this proceeding," the League's petition said, "this has resulted, in field tests and in deployments, in substantial, extremely difficult-to-resolve incidents of interference to fixed and mobile Amateur Radio facilities."
The FCC, meanwhile, "has assisted not at all, or imperceptibly, in these cases, and the BPL system operator has either been uncooperative or unable to resolve the interference," the League said.
The League said its proposed additional regulations would permit those BPL architectures that are "benign," while discouraging "first-generation interference-causing BPL configurations, unless the latter modify their systems in certain minor aspects." A "benign" system, the ARRL noted, would not apply HF signals on overhead medium-voltage lines and would include fixed, permanent notches in the amateur bands. Existing DS2 and Main.net systems can avoid HF on overhead lines and notch Amateur bands on low-voltage wiring, so the rules changes it seeks, the League said, do not ask the FCC to choose among competing technologies.
The League said the Commission "has a very short window of opportunity" to act now to rectify the shortcomings of its October 2004 Report and Order before significant access BPL deployment occurs.
Among the several BPL system designs and implementation that "have demonstrated that it is technically and economically feasible to implement BPL without creating harmful interference to Amateur Radio operations," the ARRL specifically cited the Motorola Powerline LV BPL system. Motorola's system doesn't use medium-voltage power lines, and it has been designed to preclude interference to ham radio and other licensed services.
For several weeks, ARRL and Motorola have cooperated in a BPL test stand at W1AW that has operated successfully without significant interference to Amateur Radio. The League also cited BPL systems by Current Technologies, IBEC and Corridor Systems as being among those that meet the additional requirements it's proposing. Current Technologies' BPL deployment in the Cincinnati, Ohio, area, for example, does not make use of medium-voltage lines for transmission of HF signals and utilizes the HomePlug notching protocol. Limited testing, the ARRL said, indicates that, as a result, the interference potential "is minimal relative to Amateur Radio facilities."
Incorporating three elements into the BPL rules adopted last year would essentially resolve all issues that the ARRL and the Amateur Service have with access BPL, the League said: Prohibiting all access BPL systems from using Amateur Radio allocations (except the five channels at 5 MHz, which the current HomePlug system architecture does not notch); prohibiting access BPL systems from using HF bands on medium-voltage power lines; and measuring signal decay from access BPL systems using a more accurate 20 dB/decade extrapolation factor rather than the 40 dB/decade factor the current rules support.
"In essence, the real divide is that companies such as Motorola, Current Technologies, IBEC and Corridor Systems all have designs that do not use HF at all on overhead power lines, and they avoid the use of Amateur Radio spectrum in all parts of their systems," other than at 5 MHz, the ARRL stressed.
Adopting its proposals, the League said, would result in a more robust product that meets the Commission's stated goals of accommodating BPL as an additional broadband option while protecting licensed radio services. "The present BPL rules achieve the first of the goals, but they are woefully inadequate to meet the second," the ARRL said.
"It is the Commission's obligation to recognize and utilize this opportunity and to amend its rules to protect licensed radio services for the first time in this proceeding," the ARRL concluded. "It can be done without significant system redesign by any BPL provider, and the Commission can easily accommodate the transition by re-starting the 180-day compliance period established in the Report and Order."
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