And now comes this joker who proposes that by making power lines into well
matched antennas, they can send gigibytes down those wires in front of your
house!
Earth to WA3FET... can you walk down the hall and talk some sense into this
guy, or if not maybe spill some super glue into his hard drives? :>)
Jim K8MR
------------------------------------------------------
January 5, 2005
University Park, Pa. -- Penn State engineers have developed a new model for
high-speed broadband transmissions over U.S. overhead electric power lines and
estimate that, at full data rate handling capacity, the lines can provide
bit rates that far exceed DSL or cable over similar spans.
Dr. Mohsen Kavehrad, the W. L. Weiss professor of electrical engineering and
director of the Center for Information and Communications Technology
Research, led the investigation. He says, "Although broadband power line (BPL)
service trials are now underway on a limited basis in some locations in the
U.S.,
these trials run at DSL- comparable rates of 2 or 3 megabits per second.
"We've run a computer simulation with our new power line model and found
that, under ideal conditions, the maximum achievable bit rate was close to a
gigabit per second per kilometer on an overhead medium voltage unshielded U.S.
electric power line that has been properly conditioned through impedance
matching. The gigabit can be shared by a half dozen homes in a neighborhood to
provide rates in the hundreds of megabits per second range, much higher than
DSL
and even cable."
Kavehrad adds, "If you condition those power lines properly, they're an
omni-present national treasure waiting to be tapped for broadband Internet
service delivery, especially in rural areas where cable or DSL are
unavailable."
The researchers say they are the first to evaluate data rate handling
capacity for overhead medium voltage unshielded U. S. electric power lines and
will
outline their findings at the IEEE Consumer Communications & Networking
Conference in Las Vegas, Nev., Jan. 5. Their paper is titled, "Transmission
Channel Model and Capacity of Overhead Multi-conductor Medium-Voltage
Power-lines
for Broadband Communications." The authors are Pouyan Amirshahi, a doctoral
candidate in electrical engineering, and Kavehrad.
In their paper, the authors note that the junctions and branches in the U.S.
overhead electrical grid cause broadband signals to reflect and produce
multipath-like effects on these lines.This causes degradation in power-line
broadband transmission performance and decreases transmission capacity.
Kavehrad explains, "The signal can bounce back and forth in the lines if
there is no proper impedance matching. The bouncing takes energy away from the
signal and the loss is reflected in the ultimate capacity.
"In service, performance will depend on how close the power company chooses
to place the repeaters," he adds.
The researchers are continuing their studies. Kavehrad predicts that the
engineering issues to make BPL a technical alternative to DSL and cable will be
solved. Whether it will be an economical alternative remains to be seen since
there are interference issues that have to be overcome.
The study was supported by a grant from AT&T Corporation.
**bah**
EDITORS: Dr. Kavehrad is at _kavehrad@engr.psu.edu_
(mailto:kavehrad@engr.psu.edu) or (814) 865-7179.
Contacts:
Barbara Hale (814) 865-9481 _bah@psu.edu_ (mailto:bah@psu.edu)
Vicki Fong (814) 865-9481 _vfong@psu.edu_ (mailto:vfong@psu.edu)
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