http://www2.arrl.org/news/stories/2004/06/09/2/?nc=1

NEWINGTON, CT, Jun 9, 2004 --- The National Telecommunications and
Information Administration`s comments in the BPL Notice of Proposed
Rule Making (NPRM) more clearly reveal the political face of an
agency eager and determined to sell the technology`s viability, no
matter what its own scientists have concluded. The NTIA is the
principal White House adviser on telecommunications policy and
administers federal government radio spectrum. Its largely scientific
Phase 1 report, which clearly established BPL`s interference
potential, already is part of the proceeding. The agency`s formal
comments, filed June 4, take pains to depict the technology not only
as workable but desirable to all--provided that BPL operators and
utilities are willing to jump through additional NTIA-recommended
hoops. At one point, the NTIA calls BPL ``a win-win proposition,``
claiming that its widespread deployment could lead to a reduction in
power line noise.

``Substitution of BPL emissions for the strong, much wider-bandwidth
power line noise emissions will broadly reduce risks of interference
to radiocommunications,`` the agency asserts. The NTIA says it`s
measured power line noise levels that are higher than the proposed
BPL emission limits. Existing power line noise poses ``greater local
interference risks`` than BPL would. But that prediction came with a
qualification: ``This is not to say that NTIA expects there will be a
net, nationwide reduction of interference risks; instead, NTIA
believes there will be at least partial offsetting of the
interference risks posed by BPL.``

The NTIA claims that reduction of strong power line noise ``is a
basic technical requirement`` for acceptable BPL performance at the
field strength limits the FCC has proposed and the NTIA has endorsed.
Widespread BPL deployment, the agency goes on to say, also would
provide an improved mechanism for utilities to detect and diagnose
electrical grid failures and problems.

Nowhere does NTIA acknowledge that power line noise interference to
licensed radio services already contravenes FCC Part 15 rules
regulating unintentional radiators--the same rules that apply to
power line carrier and BPL systems. The ARRL assists the FCC in
dealing with hundreds of power line noise complaints from amateurs
each year.

The agency does come close to recommending a limit on BPL signal
power to compensate for variations in power line noise, however.
``Because radio noise on power lines can vary by upwards of 20 dB
throughout a day,`` the comments said, ``a rule should require
adjustment of BPL signal power to preclude unnecessarily high levels
of radiated emissions.`` The NTIA said that while it`s still
evaluating the potential of BPL power control to reduce interference
risk, ``it is obvious that reducing Access BPL emissions by about 20
dB (a factor of 100) when noise is at relatively low levels will
substantially reduce interference risks.``

NTIA Smells a Rat?

Addressing BPL`s interference potential is a persistent theme
throughout the agency`s remarks, and sometimes its stance verges on
the overly defensive. Early on, NTIA raised the specter of coax-
munching rodents with an over-the-top example of ``suspected`` versus
genuine interference: Poor reception chalked up to BPL could turn out
to be a pest-control issue, the agency suggested in a footnote.

``For example, rodents sometimes chew coaxial cables or twin-lead
transmission lines and cause significant reductions or complete loss
of the desired signal power that should reach the receiver,`` the
NTIA said. ``In many other cases, interference is realized but not
caused by the suspected device.``

Additional Hoops

To reduce interference risks from the technology, the NTIA comments
recommend ``several new BPL rule elements`` to augment the FCC`s
proposals. ``These rules also help ensure that interference from BPL
systems would be eliminated expeditiously with little effort needed
on the part of any radio operator,`` the NTIA predicted. Its
recommendations, the agency says, shift emphasis away from
eliminating interference and toward preventing it--something it says
BPL operators have a strong incentive to do.


FCC Chairman Michael Powell surfs the `net via a BPL-provided
Internet connection in a home in Fuquay-Varina, North Carolina.
Progress Energy is conducting a BPL field trial in the neighborhood.


``NTIA believes that BPL operators, as the parties responsible for
eliminating harmful interference, will voluntarily implement
equipment, organizational elements, and installation and operating
practices that prevent interference and facilitate interference
mitigation,`` the agency`s comments state. ``Market appeal of BPL
could quickly evaporate if BPL systems were to endemically cause
interference and have to be shut down with operating authorizations
swiftly revoked if necessary.``

The NTIA recommends the FCC make its proposed BPL deployment
notification requirements retroactive. BPL operators ``should be
required to notify of planned deployments at least 30 days in advance
of implementation and to consider the coordination data they receive
regarding local radio receiver operations in order to prevent
interference,`` its comments say. According to the NTIA, such advance
notification would give ``local radio receiver operators`` a chance
to inform BPL operators of potential interference situations.

To make it possible for radio operators to diagnose suspected BPL
interference, BPL operators should provide sufficient details of the
BPL emission to enable identification using a spectrum analyzer. The
NTIA says it`s still considering the idea of a BPL system identifier
that a conventional radio receiver could detect.

The NTIA also recommends that the FCC apply its more stringent
certification, rather than verification, procedures, to authorize BPL
systems. ``Because Access BPL systems pose relatively high
interference risks, certification rather than verification should be
required,`` the NTIA advised. Certification would require independent
testing, as opposed to having a BPL operator merely attest that its
system complies with FCC rules.

Key Phase 2 Study Findings Included

As Acting NTIA Administrator Michael Gallagher indicated in May (see
``NTIA Head Tips Hand on Agency`s Additional BPL Findings``), the
comments include some key findings of his agency`s pending Phase 2
BPL study, set for release later this year. The Phase 2 study will
provide ``additional guidance`` on contending with BPL interference
issues, but the NTIA says it doesn`t want the FCC to hold up the
proceeding until the report`s release. Its comments urge the
Commission to ``promptly adopt effective technical rules`` to enable
BPL development and implementation. The FCC has extended the reply
comment deadline to June 22 to allow stakeholders time to review the
NTIA`s comments.

The agency`s Phase 2 study will, among other things, assess
interference risks due to aggregation (ie, total emissions from
multiple BPL systems) and ionospheric propagation of interfering
signals from BPL systems. The NTIA says it`s determined that BPL
aggregation and ionospheric propagation ``is not a potential near-
term problem.``

The NTIA predicts that hundreds of thousands and ultimately millions
of BPL devices could be deployed under the rules the FCC is expected
to adopt before ionospheric propagation and aggregate BPL emissions
become a serious interference issue.

The Phase 2 study also will evaluate the effectiveness of proposed
Part 15 measurement techniques. The NTIA`s comments include the
study`s recommendation for a ``height-correction factor`` of 5 dB to
BPL measurements made at a height of 1 meter. The NTIA has
acknowledged that peak field strength from a BPL device can be as
much as 20 dB higher than the peak measured at a height of 1 meter
under current Part 15 rules. Because the peak does not occur
consistently at a particular distance from a BPL device, peak field
strength must be determined by tracking the entire power line, the
NTIA advises.

The NTIA also suggests coordination areas in which a designated
authority would coordinate all planned BPL deployment. It also wants
to exclude certain specific bands and frequencies and geographical
areas to protect critical federal government systems. The agency
further proposes that BPL rules provide for prompt response to
complaints of suspected interference. Shutting down the system,
however, would be a last resort, in the NTIA`s view.

The NTIA said its ``refinements`` to the FCC-proposed BPL rules
``will fully alleviate the concerns of all parties`` to the BPL
proceeding. It left the door open to further study of various
technical issues.

``Moreover, these rules create an environment in which BPL proponents
can properly gauge investment risks and fulfill the protection
requirements of radio communications,`` the comments conclude. The
NTIA`s comments in ET Docket 04-37 are available on the NTIA Web
site.

For additional information, visit the ``Broadband Over Power Line
(BPL) and Amateur Radio``page on the ARRL Web site. To support the
League`s efforts in this area, visit the ARRL`s secure BPL Web site.

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Reserved. (via John Norfolk, dxldyahoogroups)