BPL Advocates' Comments Lack Technical Substance, ARRL Reply Comments Say:

The ARRL says Broadband over Power Line (BPL) proponents failed in their comments to the FCC to substantiate their claims that the technology will not cause widespread interference. In reply comments filed August 20--the FCC's deadline to receive comments in the Notice of Inquiry, ET Docket 03-104--the League said that if the FCC is going to rely on industry statements in making decisions on BPL deployment, the industry should back up its assertions with technical studies and hard data and make these public.

"Unfounded assurances that BPL will not cause interference are no substitute for real-world measurements," the League declared, "and the FCC should rely on documented test results and an impact of interference potential based on scientific, not marketing, criteria."

A form of power line carrier--or PLC--technology, BPL would use existing low and medium-voltage power lines to deliver broadband services to homes and businesses using frequencies between 2 and 80 MHz. Some BPL proponents--primarily electric power utilities--already are testing BPL systems in several markets and want the FCC to relax radiation limits.

"Power lines are ubiquitous, and attempts by the BPL industry to obtain relaxed emission classifications based on operating environment are obviously illogical and frivolous," the ARRL said. BPL would impact not only hams but public safety low-band VHF systems and other mobile systems, the League's comments added.

In contrast to the BPL advocates' "blanket statements" of no interference from BPL field trial sites, the ARRL said its own field tests "lead inescapably to the conclusion that BPL will, if deployed, create widespread harmful interference." It predicted signal levels of up to 30 dB over S9 on a typical amateur transceiver, "well beyond what would preclude amateur HF communications entirely."

To dramatize its point, the League urged the Commission to view video http://www.arrl.org/tis/info/HTML/plc/#video shot during recent ARRL test-and-measurement forays to BPL field trial communities in four states. The ARRL said the type of degradation expected from BPL would transform 20 meters from a band with worldwide communication capabilities to one of limited regional communication capability.

"ARRL has, in fact, done what the BPL industry should have done--brought an amateur station to the trial area," the League said. "When it did so, the interference was manifest and widespread and would be so even to an untrained observer."

The League also noted that comments in the proceeding so far have been silent on the interference susceptibility of BPL to ham radio signal ingress. The League predicted that even as little as 250 mW of signal induced into overhead power lines some 100 feet from an amateur antenna could degrade a BPL system or render it inoperative.

The ARRL called on the FCC to stop acting like a cheerleader for BPL. "It is past time that the Commission acted in its proper role as a steward of the radio spectrum and recognized the interference potential of BPL to the sensitive incumbent licensed services in these bands," the League concluded. "The Commission cannot stretch the Part 15 regulations as far as would be required to accommodate BPL."

The League's complete reply comments are available on the ARRL Web site http://www.arrl.org/announce/regulatory/et03-104/reply-comments-index.htm l along with more information ttp://www.arrl.org/news/features/2003/07/08/1/. Additional information and video clips are on the ARRL "Power Line Communications (PLC) and Amateur Radio" page http://www.arrl.org/tis/info/HTML/plc/.

To support the League's efforts in the BPL fight, visit the ARRL's secure BPL Web site https://www.arrl.org/forms/development/donations/bpl/.

Source:

The ARRL Letter Vol. 22, No. 33 August 22, 2003

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