said by W1RFI :

> I think we can find a way for both to coexist.

Actually, on behalf of ARRL, I have been working to do just that.

I first must note, however, that calling Amateur Radio a "1927 technology" is not going to accomplish coexistance in any form. Amateur Radio uses a wide variety of operating modes, from simple Morse code through digital, television and even satellites, with communications satellites built and lauched by hams. And we won't even get into the public-service value of Amateur Radio. That sort of language is intended to be inflammatory. It bad enough when some of the BPL organizations use terms like "armchair amateurs using vacuum tube technology," but if we are to have a rational discussion, such trolling should not be used here.

For BPL to coexist with licensed radio services, it simply has to avoid any and all spectrum that is use near it (typically a few hundred feet to as much as a mile away from wires carrying BPL). BPL operating at the FCC limits can be as much as 60 dB stronger than the local noise floor. (That is a factor or 1,000,000X power).

To avoid interference, BPL must filter the spectrum it doesn't use to a good-enough degree that it doesn't cause objectionable noise to the nearby use of radio spectrum. (For a good example of what "objectionable" means, ask yourself how much noise you would tolerate on your routine use of your home telephone.)

There has been progress made on the coexistance front. To date, Amperion, Current Technologies, Motorola (now out of the access BPL market), Mitsubishi (now out of the North Amercian BPL market), Corinex, IBEC and Kaicom -- most BPL manufacturers, are actively working with ARRL on interference mitigation, and trying different system configurations and designs. (Main.net is not yet actively working with ARRL, but recently, one of their engineers approached me to note that their new systems are an improvement over what was seen in Manassas, so ARRL and Main.net are basically talking about working together.) At this point, most, but not all, BPL manufacturers are working with ARRL toward coexistance with Amateur Radio.

The results have been encouraging. First out of that gate was HomePlug technology, which implemented its first-generation product with spectral masks to protect Amateur Radio, and has maintained that design technique through two generations, into HomePlug AV, the 200 Mb/s technology. (See »p1k.arrl.org/~ehare/bpl/HomePlug_ARRL.pdf).

Current Technologies, the BPL manufacturer whose equipment is being used in Cincinnati, OH and Dallas, TX uses HomePlug technology on the 240-volt wiring, and 32-48 MHz on overhead power lines. The result? In both cities, BPL is deploying without major interference problems.

DS2, a BPL-chipset manufacturer, has also worked closely with ARRL, as have many of its customers, making modems using DS2 ICs. DS2 improved the performance of its filtering, with the result that ARRL site visits to several DS2-based areas (Houston, TX; Springfield, MA;Bowling Green, OH and San Diego, CA) showed that the improved notching significantly improved the EMC performance of the system, to the point that mobile Amateur Radio operation, and presumably most fixed operation, was not seeing widespread harmful interference.

There is still work to go. In most cases, these improvements have not been demonstrated by all of the BPL manufacturers in larger deployments. (Cincinatti, Dallas and Houston are pretty large at this point, so those are exceptions). BPL organizations like UPLC.org have not (yet?) demonstrated any real spirit of mutual cooperation, and ARRL does not work with them the way it does with HomePlug, the Home Phone Networking Alliance, the DSL committees and the National Cable Telecommunications Society, to name a few.

Organizationally, the industry is missing the EMC boat, and UPLC is doing little or nothing to try to open that door, despite some prodding from some of its member companies. But ARRL has been able to an end run around that general non-cooperative approach and directly approach many of the BPL manufacturers, integrators and electric utilities and accomplish a start of what it has been able to do for other industries such as cable and DSL -- prevent most interference before it happens, and develop solutions for the remainder.

Another major hole thus far is in the industry standards area. There are successful models for BPL deployment, but the industry has generally blocked the inclusion of those models in industry standards. (Although it does remain to be seen how these standards hold up to the ballot process. Under the IEEE model, the group that votes on a standard is not necessarily the same group that created it.)

I must add that all of the above applies to Amateur Radio spectrum. So far, none of the BPL operations are making any attempt to avoid the use of the international shortwave broadcast bands. The SW listeners, however, are not filing complaints, but most may not know what the noise source is, know that they can complain or want to literally make a federal case out of noise on their SW listening.

Ed Hare, W1RFI
ARRL Laboratory
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Web: »www.arrl.org/bpl