[UK-CONTEST] Power Line Transmission

[G3SJJ]

This is already happening in States, like the weather it will eventually
come our way. An article in the Wall Street Journal has prompted a response
from ARRL.   I wonder what the MOD would say if 5MHz was wiped out because
of PLT. (We call it PLT, US calls it BPL.  Chris G3SJJ



-----Original Message-----
    From: Sumner, Dave, K1ZZ

    Sent: Tuesday, March 02, 2004 5:51 PM

    To: 'ned.crabb at wsj.com'

    Subject: Letter to the Editor re "The Web's New Outlet"



    The following was just sent to you by FAX on ARRL letterhead.

    David Sumner

    Chief Executive Officer

    ARRL, the National Association for Amateur Radio

    (860) 594-0205 (direct line)

    March 2, 2004

    Editor, Wall Street Journal

    200 Liberty St.

    New York, NY 10281

    To the Editor:

    Regarding "The Web’s New Outlet" (page B1, March 2 WSJ), any listing of
the pros and cons of using power lines to deliver broadband services must
mention its major disadvantage: it pollutes the radio spectrum, interfering
with nearby radio receivers. The only known exception is a microwave system
being developed by Corridor Systems of Santa Rosa, California.

    What the FCC calls Broadband over Power Line (BPL) amounts to sending a
wideband radio signal over unshielded wires that were not designed for the
purpose. Power transmission lines are designed to carry alternating current
at 60 Hz. They do not work at all well for the transmission of the higher
frequencies, between 1.7 and 80 MHz, that are used in BPL systems. Instead,
because they operate according to the laws of physics, they function much
like antennas. Radio receivers in the vicinity pick up the BPL signal, which
overrides and interferes with radio reception. The frequencies in question
are used by public safety agencies, the military, aeronautical and maritime
services, broadcasters, radio astronomers, radio amateurs, and others. The
frequency range includes the unique and very narrow portion of the radio
spectrum in which the ionosphere supports worldwide communication.

    BPL system designers have tried to address the problem by notching
certain frequencies, but with only limited success. Yet BPL implementation
cannot go forward without solving it, because for very good and obvious
reasons it is a violation of FCC regulations for a BPL system to cause radio
interference. If BPL causes interference - and it does (see references) -
the BPL system must be shut down.

    Potential investors in broadband delivery alternatives to DSL and cable
would be far better off considering the various methods of delivering
fiber-to-the-home in densely populated areas. For rural areas, adaptations
of wireless LAN technology are generally recognized as offering far more
promise than BPL.



    Sincerely,

    David Sumner

    Chief Executive Officer

    dsumner at arrl.org

    _____

    References:

    The ARRL has documented interference in all four of the
BPL-marketing-trial areas in the US that we have visited. Other Amateur
Radio societies have also documented interference from trials in their
countries. The following link has links to the ARRL video and many of the
audio and video recordings made from BPL trial areas around the world. See:
http://www.arrl.org/tis/info/HTML/plc#video

    Another link is: http://www.oe3mzc.oevsv.at/powerline/video.htm -
Austria

    Although these videos show interference to amateur radio, BPL can and
does use spectrum throughout HF/shortwave and VHF. Other significant users
of that spectrum include government, military and international shortwave
broadcasting. For evidence of interference to shortwave broadcasting, see:
BBC R&D White Paper, "The effects of power-line telecommunications on
broadcast reception: brief trial in Crieff,"
<http://www.bbc.co.uk/rd/pubs/whp/whp067.html>

    Aeronautical Radio Inc documented interference to HF aeronautical
communications from a similar device:
http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_documen
t=6514683399

    There are many other questions about BPL. A very interesting independent
analysis of the economic issues confronting BPL is at:
http://intel.si.umich.edu/tprc/papers/2003/246/Tongia-PLC.pdf

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