[TWIAR] FEMA says power line broadband threatens its radio system

[Greg Williams]

By Joab Jackson
GCN Staff

Responding to a Federal Communications Commission inquiry, the Federal
Emergency Management Agency has warned that sending data through power lines
could disrupt FEMA's National Radio System.

The Homeland Security Department is responding to a notice of inquiry
(http://edocket.access.gpo.gov/2003/03-12914.htm ) issued last May by the
FCC on whether, or how, the agency should regulate an emerging technology
called broadband over power line, or BPL.

BPL systems use live utility company power lines as a conduit for data
transmission by modulating radio frequency signals that are coupled with
electricity transmissions. The technology could be offered to consumers as
an alternative to cable modem and digital subscriber line service. Although
no services are now offered, several companies have introduced products that
let users send data over the power lines within their own homes. The FCC
asked for more information on what effect power line radio signals would
have on other licensed radio technologies using those same frequencies.

FEMA responded
(http://gullfoss2.fcc.gov/prod/ecfs/retrieve.cgi?native_or_pdf=pdf&id_docume
nt=6515292045 ) earlier this month to the inquiry, stating that it had
"grave concerns" about how the technology would affect its National Radio
System

The radio system, which works with shortwave radios, is FEMA's backup
command and control communications media, and was designed to interface with
the radio systems of other agencies during times of disaster.

"By design, BPL systems use radio frequency energy on unshielded, unbalanced
transmission lines, resulting in the unavoidable radiation of [radio
frequency] energy," the response read. This unintentional radiation will
create harmful interference to licensed radio services throughout the [high
frequency] and lower [very high frequency] spectrum." Alan Shark, president
of the Power Line Communications Association, said that FEMA's concerns were
overblown. Most first-responder radio systems work in the 800-MHz range, far
above the usual operating range of power line equipment, which can run from
1 MHz to 300 MHz.

Shortwave radios, also called high-frequency radios, do operate in about the
same range as power line equipment, he said. Not surprisingly the National
Association of Amateur Radio, whose members volunteer their services during
times of crisis, are also protesting
(http://www.arrl.org/tis/info/html/plc ) the BPL technology.

Shark said that BPL equipment vendors have done studies on whether
additional interference comes from their products, and have failed to find
any interference beyond what the power lines themselves cause. Both the FCC
and the National Telecommunications and Information Administration also are
conducting studies to measure interference levels.




Greg Williams
k4hsm@lock-net.com

Tis often better to be silent and thought a fool rather than to speak and
remove all doubt.
No trees were destroyed in the sending of this contaminant-free message
We do concede, a significant number of electrons may have been
inconvenienced.