Power line communication: Encyclopedia II - Power line communication - Potential for Interference

Power line communication - Potential for Interference

Some groups oppose the proliferation of this technology, mostly due to its potential to interfere with radio transmissions. As power lines are typically untwisted and unshielded, they are essentially large antennas, and will broadcast large amounts of radio energy (see the American Radio Relay League's article). Because of their lack of shielding, the BPL systems are also at risk of being interfered with by outside radio signals.

Recently, power and telecommunications companies have started tests of the BPL technology, over the protests of the radio groups. After claims of interference by these groups, many of the trials were ended early and proclaimed successes, though the ARRL and other groups claimed otherwise. Some of the providers conducting those trials have now begun commercial roll-outs in limited neighborhoods in selected cities, with some level of user acceptance. There have been many documented cases of interference reported to the FCC by Amateur Radio users. A video clearly showing the interference at a site at Briarcliff Manor, NY is available on the ARRL website. Because of these continued problems, Amateur Radio operators and others filed a petition for reconsideration with the FCC in February 2005. Austria, Australia, New Zealand and other locations have also experienced BPL's spectrum pollution and raised concerns within their governing bodies. In the UK, the BBC has published the results of a number of tests to detect interference from BPL installations. They have also made a video (Real Media format), showing broadcast of data and interference from in-home BPL devices.

New FCC rules require BPL systems to be capable of remotely notching out frequencies on which interference occurs, and of shutting down remotely if necessary to resolve the interference. BPL systems operating within FCC Part 15 emissions limits may still interfere with wireless radio communications and are required to resolve interference problems. A few early trials have been shut down, though whether it was in response to complaints is debatable.

Recently, Motorola has announced a new Low Voltage Access BPL system that has a reduced potential for interference over the Amperion Inc. and Current Technologies LLC systems. The American Radio Relay League was invited by Motorola to participate with these tests, and even installed the Motorola system at their headquarters. Preliminary results were very positive with regard to interference.

Power line communication - FCC

On October 14, 2004, the U.S. Federal Communications Commission adopted rules to facilitate the deployment of "Access BPL" -- i.e., use of BPL to deliver broadband service to homes and businesses. The technical rules are more liberal than those advanced by ARRL and other spectrum users, but include provisions that require BPL providers to investigate and correct any interference they cause. These rules may be subject to future litigation.

Adapted from the Wikipedia article "Potential for Interference", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki