BPL is far from the only way to deliver broadband to end users. Each of the following are mainstream broadbands technologies serving hundreds of thousands -- or millions -- of users today:

• Cable
• DSL
• Commercial licensed wireless
• Commericial unlicensed wireless
• Wi-Fi community networks
• Cellular telephone
• Satellite

In most cases, BPL is far from the "best" way to deliver broadband. It needs repeaters installed on the medium-voltage distribution lines every 2000 feet or less. Those lines were not designed to carry broadband signals. To the contrary, they were designed to carry 60 Hz AC [alternating current] power and are a pretty poor conductor at radio frequencies. It is a noisy environment, and leakage from those overhead wires is assured, as it ingress -- the leakage of licensed services' transmitters into the wires. One has to note that if coaxial cable and Category 5 (or higher) wiring weren't needed to carry broadband signals reliably, they would never have been invented.

I attended a presentation given by Ron Hranac, a member of the Society of Cable Communications Engineers Board of Directors. Hranac outlined the improvements that need to be made to a well-maintained cable plant to make it work reliabily for broadband use. Things like the phase characteristics and gain flatness of the system need to be closely controlled. The idea that all that really isn't needed, and that one can just put those signals onto any old wire, is not technically supportable. See "Deploying VOIP on the outside plant" (at http://p1k.arrl.org/~ehare/ARRL_EMC_Committee/Deploying_VoIP_on_the_Outside_Plant_files/frame.htm and BPL Presentations (at http://www.arrl.org/tis/info/HTML/plc/presentations.html).

There is no doubt at all that BPL can and does cause interference locally on any spectrum it uses, if that spectrum is in use locally. In residential neighborhoods, this includes Amateur Radio, CB and the reception of international broadcast. Some BPL manufacturers have made progress at filtering their equipment well enough to avoid interference to Amateur Radio, although some have not. The BPL operator in Manassas, VA, for example, has been embroiled in an interference battle for over a year. The FCC recently had to require that BPL operator to report how it would notify its customers in the event that the FCC ordered it to shut down.

BPL is not without its uses, and other than the interference issues, ARRL is not opposed to BPL deployment. To the contrary, we have a BPL system test operating here at ARRL HQ, in full cooperation with Motorola, the BPL manufacturer. But for BPL to live up to its potential, it must address its interference problems head on, and live within the limitations of a noisy environment using wires not ideally suited to the task. So far, some companies have made progress with the former. The latter is being addressed through the use of repeaters and amplifiers located at intervals much closer to gether than other technologies using better-suited wiring need to use.

Ed Hare, W1RFI, is the ARRL Laboratory Manager. He is a member of the ASC C63 EMC Committee and chairman of Subcommittee 5, Immunity and Ad hoc BPL Working Group. He is also a member of the IEEE P1775 BPL EMC Committee, IEEE, Standards Association, Electromagnetic Compatibility Society, and IEEE SCC-28 RF Safety. He is a member of the IEEE EMC Society Standards Development Committee and chairman of the BPL Study Project. He is also a member of the Society of Automotive Engineers EMC/EMR Committee and is on the Board of Directors of QRP Amateur Radio Club International. ARRL's general information on BPL is available from http://www.arrl.org/bpl.