ARLA/CLUSTER: Fwd: [BPLandHamRadio] Re: Claims that Australian
broadband powerline regulations breach WTO treaties
Carlos Mourato
radiofarol gmail.com
Sábado, 16 de Janeiro de 2010 - 12:43:30 WET
---------- Forwarded message ----------
From: Hare, Ed W1RFI <w1rfi arrl.org>
Date: 2010/1/16
Subject: RE: [BPLandHamRadio] Re: Claims that Australian broadband powerline
regulations breach WTO treaties
To: BPLandHamRadio yahoogroups.com
That should still hold when we have more sunspots, perhaps even more so.
The testing done involved turning off the carriers in the broadcast band
when the modem detected strong signals from SW BC stations. When those
carriers were turned off, in three of four cases tested, the data rate the
modems could achieve dropped by no more than a few percent. My conclusion
from those results was that the tradeoff was a reasonable one -- by notching
as needed to protect licensed reception, the BPL system can continue to
function.
In the fourth case, the data rate *increased* when the adaptive notching was
turned on! My speculation is that the strong BC signals were interfering
with the modem. Those carriers were already lost to the system, and the
overhead of trying to reconstruct the data stream from the other available
carriers did chew up some of the data rate. When the unsuable carriers were
no longer used, the system did not need to try to rebuild the data stream,
and the speed improved slightly.
No matter which way you look at it, turning off carriers to avoid local
licensed users is a useful tool to allow BPL to deploy successfully. IMHO,
the nature of the Amateur Radio Service is such that the carriers should be
permanently notched. This is a model used by HomePlug, the Home Phone
Networking Alliance and the newer high-speed DSL services. The broadcasters
are apparently satisfied that adaptive notching can protect the shortwave
broadcast bands. The Citizens Band allocations should also be notched.
Other local use can probably be identified from licensing databases and
notched as needed.
One need only look at the results to see that interference problems harmed
the BPL industry. To quote John Joyce, the CEO of the Ambient Corporation:
"BPL does not perform well in the overhead U.S. electrical distribution
topology, and thus today a BPL signal cannot communicate over long distances
or through a transformer without couplers and repeaters to boost the signal.
This additional equipment increases overall deployment costs and eliminates
cost savings associated with using the existing wires. . . There are
further problems in transmitting BPL signals over power lines, including
interference issues caused and experienced by a BPL system. Overhead
electrical distribution wires are unshielded from radio frequency (RF)
interference, therefore, BPL signals traveling on medium-voltage overhead
lines have the potential to interfere with shortwave radio operators. Local
RF using unlicensed spectrum also can interfere with the BPL network signal,
and because the spectrum is unlicensed, mitigation can be timely and
costly."
I and many other hams raised those issues early on. Those concerns were met
with absolute denial. The result is as seen above, and BPL systems that
could have been showpieces were instead shut down by utilities, often at
considerable cost. (IDACorp shut down IDAComm and announced that its foray
into BPL cost it $10M US.) Those same hams worked hard to help this
industry resolve those problems. At this point, we know what works. It
doesn't appear that the industry, however, has really learned from the
lessons of the past, because even after all this, even after having
solutions at hand that have the support of licensed radio users, it
systematically avoids incorporating those good solutions into regulation and
standards that could help everyone feel that the past is behind them.
The food fights in the IEEE P1775 EMC standard group go on to this day,
where the group would not include a number of key points that the industry
is already doing as standard practice. The result is that the IEEE EMC
Society, a co-sponsor of the standard, provided comments to the Working
Group during the balloting process, to try to help it understand some of the
EMC issues that are not done correctly in the standard. If the WG doesn't
take that seriously, the end result will be another opportunity lost, as
there will be a standard that doesn't have the support of the very
stakeholders the standard is intended to serve. The BPL industry has
bemoaned that the lack of standards has held it back. Yet it is developing a
standard that does NOT have the support of key stakeholders. A standard that
serves to deepen the chasm that separates stakeholders is, in some ways,
worse than no standard at all.
The ironic part is that there are a number of BPL companies that have been
leaders in trying to address interference. IBEC and Current Technologies
come to mind. Yet these very companies are also leaders in trying to keep
that successful model out of the regulations and standards that are still
under development. Current's staff have been very active in P1775, fighting
fiercely to keep notching, notch depth and limits out of the standard.
IBEC has consistently voted the same way.
We all know what works:
1. Notch the ham bands.
2. Do so with state of the art filtering of -35 dB.
3. Measure systems correctly. to ensure that the system does not exceed the
emissions limits. This requires a scientifically justified, not politically
justified, extrapolation factor.
I have seen this work, and reported so publicly. In Houston, the BPL system
was notched to protect the ham bands and I did not see widespread
interference, just a few dB (very few) of BPL noise directly under a few
injection points.
Take this successful model and turn it into good regulation and standards.
This will help all stakeholders and finally allow the spectre of
interference to be put back in the box. The industry can then find its
natural place in access BPL and smart-grid deployments.
73,
Ed Hare, W1RFI
ARRL Laboratory Manager
225 Main St
Newington, CT 06111
Tel: 860-594-0318
Email: W1RFI arrl.org
------------------------------
*From:* Barry White [mailto:bewhite bigpond.net.au]
*Sent:* Fri 1/15/2010 11:28 PM
*To:* BPLandHamRadio yahoogroups.com
*Subject:* Re: [BPLandHamRadio] Re: Claims that Australian broadband
powerline regulations breach WTO treaties
Hello Ed,
I noted this comment from your response;
An ETSI study (ETSI TR 102616) shows that adaptive notching used to protect
HF SW BC did not have a major effect on data rates.
Do you think this will be still valid when the sunspot cycle gets back to
normal ?
Here in Australia we have very strong signals from many Asian SW BC stations
in normal times on a north south path.
73 Barry VK2AAB
Hare, Ed W1RFI wrote:
Hi, Glenn,
My main role in that filing was to prepare Exhibit A. My usual technique is
to provide whatever technical paper may be appropriate, and separately,
offer my input to Chris on the remainder of the filing. The major points in
Imlay's work were the legal points he raised, though. I do offer some views
on that once in a while, but Chris is much smarter at that than I am.
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Best 73 from: regards from: CT4RK Carlos Mourato - Sines - Portugal
Save the Radio Spectrum! Eliminate Broadband over Power Line. Salve o
espectro electromagnético!. Não use a rede electrica para transmitir dados.
Os "homeplugs power line" e a tecnologia "power line" causa fortes
interferencias noutro serviços sem voce se aperceber. Diga não à tecnologia
power line. Proteja o ambiente
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