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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. 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.
New Powerline modes are able to detect the existence of SW-Radio services at the
location and time of operation by monitoring the ground noise at the socket
where the modem is connected to. The frequencies allocated by radio broadcast
will be omitted from Powerline communication. Such new technologies remove
interferences from powerline modems to SW-Radio broadcast.
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