[PPRAANet] FW: [cq-l] NTIA Reports on BPL Interference Study

Wed, 28 Apr 2004 19:24:40 -0500

Hello everyone,

I am forwarding the first announcement of the release of the NTIA's report
on the interference potential of BPL.  I am reviewing it right now, but CQ's
initial assessment of the report is that it doesn't paint as rosy a picture
of BPL as the FCC contends.  I will incorporate some of this into the
PPRAA's letter to the FCC, which I hope to put out on the reflector for
everyone to review later tonight or tomorrow

73
Al VO1NO / W0

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of
[email protected]
Sent: Wednesday, April 28, 2004 2:55 PM
To: [email protected]
Subject: [cq-l] NTIA Reports on BPL Interference Study

>From the CQ Newsroom:

The National Telecommunications and Information Administration (NTIA) has
issued its long-awaited report on the interference potential of Broadband
over Power Lines (BPL). Despite a generally-glowing news release, the report
itself identifies significant interference risks from BPL and concludes that
the methods currently used for measuring BPL noise levels are inadequate and
that more study is needed on such areas as ionospheric propagation of BPL
signals.

The full report may be downloaded, either in full or chapter by chapter,
from the NTIA website at: <http://www.ntia.doc.gov/new.html>. Our summary of
the report's major findings follow.

CQ Summary of NTIA report to the FCC on BPL:

NTIA concluded�
1) �that the methods currently used to measure noise levels and interference
potential are inadequate:   �(A)pplication of existing Part 15 measurement
procedures for BPL systems results in a significant underestimation of peak
field strength. Underestimation of the actual peak field strength is the
leading contributor to high interference risks. As applied in current
practice to BPL systems, Part 15 measurement guidelines to not address
unique physical and electromagnetic characteristics of BPL radiated
emissions.� (Executive Summary)

2) � that noise levels must be measured from BPL-energized power lines as
well as the �device� coupling the signal to the power lines: �BPL systems
generate the highest electric field strength near the BPL device for
horizontal-parallel polarized signals. However, these systems generate peak
vertically-polarized field strength under and adjacent to the power lines
and at impedance discontinuities at substantial distances from the BPL
device.� (Executive Summary)

3) � that interference to weak-to-medium strength signals is likely out to
460 meters (1500 feet; more than 1/4 mile) from a BPL noise source at ground
level  and out to a 40-kilometer (25 mile) radius from the signal source for
an airplane at an altitude of up to 6 kilometers (approx. 20,000 feet):
�Interference to land vehicle, boat, and fixed stations receiving
moderate-to-strong  radio signals is likely in areas extending to 30 meters,
55 meters, and 230 meters, respectively, from one BPL device and the power
lines to which it is connected. With low-to-moderate desired signal levels,
interference is likely at these receivers within areas extending to 75
meters, 100 meters and 460 meters from the power lines � (I)nterference to
aircraft reception of moderate-to-strong radio signals is likely to occur
below 6 km altitude within 12 km center of the BPL deployment. Interference
likely would occur to aircraft reception of weak-to-moderate radio signals
within 40 miles of the center of the BPL deployment area. (Executive
Summary)

4) � that results of BPL tests and implementations in other countries have
been mixed: �BPL apparently has been implemented with success in some
countries, while other countries have postponed implementation of BPL
systems until further interference studies are � conducted. Still others
have withdrawn their approval for operation of BPL systems after
experiencing interference problems.� (Section 9, Summary of Results). One
example cited was that �(d)uring an emergency exercise of the Austrian Red
Cross in May 2003, communication was massively disturbed by (BPL), with
interference levels exceeding the limits by a factor of 10,000.� (Appendix
B)

5) � that more study is needed in several important areas, including skywave
propagation of BPL signals, that it will conduct further studies and issue a
report later this year: �NTIA will complete a Phase 2 study later this year
that will assess the potential interference risks due to aggregation and
ionospheric propagation of interfering signals from BPL systems; refine and
apply BPL deployment models; and evaluate the effectiveness of proposed Part
15 measurement techniques.� (NTIA News Release)

NTIA is recommending more stringent measurement standards and procedures,
along with several interference mitigation techniques  some not mentioned in
the NPRM  although it admitted that the nature of power lines and of BPL
would limit the effectiveness of some of them. Additional recommendations
are likely after the second phase of the NTIA study is completed later this
year. Acting NTIA Administrator Michael Gallagher called the NTIA
recommendations �the technical foundation for the responsible deployment of
broadband over power lines.�

CQ Opinion: It is clear from the results of the NTIA study that the FCC�s
rulemaking proposal is premature at best, and it would be irresponsible of
the FCC to go forward in enacting BPL rules before the NTIA Phase 2 study is
completed later this year.

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