Chip, As much as I respect your knowledge there are BPL issues that are
simple to understand and problems that have not been resolved.
Fractenna wrote:
BPL comes into your house at the power company service box. Even if you
don[sic] not connect to it.
FACT: The Cedar Rapids deployment has a WLAN link from the pole. The wires
carry the 2-80 MHz. How does that go from 2-80 MHz --into-- the house?
SNIP: Well Chip, since the pole is only 20 feet from the ham shack ...
What can I expect if it deploys here in suburban Concord NH?
30 uV/meter [AKA ~ S9] at 7 meters from the pole is pretty significant
when my station is 7 to 10 meters meters from the pole.
Cedar Rapids ... see below.
It creates S9++ signals from 2 to 80 MHz.
FACT: Sure, if you drive your 1972 Nova with 'HAM ON BOARD' sticker (for
example) under the power line, this is a consistently true statement.
SNIP: Well Chip, since 30 uV/meter at 10 meters puts me [at 7 to 10
meters from the pole] in the fairly close field what will my noise
levels be?
Otherwise, there are some, few, circumstances in which an unacceptabel (pun
and sic intended) level of 'hash' will arise in that passband to the annoyance
of some hams. Based on assumption, the number of hams affected nation wide is
in the hundreds.
SNIP: There is NO BASIS for that assumption!! BPL has not been tested in
an densely Amateur Radio populated community. I live in a small town of
slightly more than 4500 people and we have eight [8] hams in town. There
is approximately one [1] amateur operator for every 420 citizens of the
USA. [700,000 hams/300 million citizens]. Where is the BPL data to
support that assumption?
For comparison, the number of hams affected by tower erection
restrictions is in the tens of thousands.
SNIP: Red Herring ... non sequitor. But, they can still operate with
'stealth antennas' and a quiet environment.
You can't hear anything on your new 10,000 dollar ICOM 7800 or any other
radio except 'Data Hash'.
FACT: Sure, if very nearby and unfiltered, this could be a problem. However,
the FCC rules require filtering for RFI mitigation in such circumstances.
SNIP: The ARRL has entered the case of W0SR because mitigation has not
worked after more than 2 months of effort in the case of Jim Spencer,
W0SR, in Cedar Rapids Iowa, reference your statement above. Jim is in a
BPL test area and has been off the air for two months while the supplier
has tried unsuccessfully to mitigate the noise.
Reference http://www.arrl.org/news/stories/2004/06/15/2/
Boeing, a highly reputable Aerospace and Civil Aviation Corporation has
made the following comment:
"Boeing told the FCC that Commission-proposed interference mitigation
techniques "are INADEQUATE [emphasis added] to protect safety of life
aeronautical HF communications services." The aircraft manufacturer
urged the FCC to "carefully investigate these issues" before adopting
rules to authorize BPL networks in spectrum used by aeronautical HF
radio services."
[Ref: http://www.arrl.org/news/stories/2004/06/24/1/?nc=1
Is that clear enough??
SNIP: The original request was for a simple and clear statement of the
issue. I offer that I made a simple [elementary school level] level of
issue statement. Make the principle point so that it is understood [As a
former teacher you recognize that a little hyperbole is an acceptable
part of the teaching tool]. Once the principle is understood then
advancing the discussion to a higher more mature level of understanding
is possible.
FACT: A vocal minority of hams want to 'kill BPL'. As opposed to working with
the power companies to fix the problem.
SNIP: In the absence of data to the contrary, I refuse to believe that
there is a non vocal majority who are advocating BPL. [The antithesis to
your hypothesis].
FACT: The press has used this exchange, in many circumstances, to view us with
the jaundiced eye of being anti-technology and very out of date. Why is it that
they just don't see it as reason to 'kill BPL'?
Once again, STILL ??, the press is/maybe wrong!!
I understand that on 22 June 2004 President Bush made the following
comments in a speech to the Department of Commerce.
" ... We need to get broadband to more Americans and so, therefore, I
want to talk about two other ways to get broadband to the consumer. We
need to use our power lines better. They go everywhere. It seems to make
sense, doesn't it, if what you're looking for is avenues into the home.
Well, electricity goes into the home. And so one great opportunity is to
spread broadband throughout America via our power lines.
And one of the problems we've got here is that the Commerce Department
has had to develop technical standards that will make sure that our
broadband can go across power lines without unnecessary interference. So
it's a technological problem. It's a technological issue. It turns out
that sometimes the competition of broadband and electricity just doesn't
go too good across one line. And so -- if I could put it in simple
vernacular. And so, therefore, the Commerce Department is helping to
sort through these issues so that broadband access will be available
through -- by our power companies..."
[Ref: http://www.whitehouse.gov/news/releases/2004/06/20040624-7.html
So, the executive branch has made up it's mind. I wonder if there is
credible and competent technical dissent in the Department of Commerce?
Chip, I am still waiting for public disclosure on successful mitigation
techniques. My suspicion is that when Hams complain at a later date the
argument will be dismissed as 'you had you chance and didn't make your
case'. Capital Investment wins...
Successful mitigation for the Amateur Radio market requires suppressing
8 portions of the HF spectrum for a total of 4.25 MHz [Ham and MARS] or
15% of the available spectrum. Other licensed services will also require
some level of mitigation. Where is the data that supports a successful
mitigation technology? How much suppression is required and under what
conditions ... -40 dB, -50 dB, etc. What is the capital investment for
suppression? Is the Rate of Return equitable for our investors? What are
the HF susceptibilities to 1.5 KW PEP within those 8 HF segments? Are
additional suppression techniques required for susceptibility? Will
susceptibility issues be local or distributed? What about the capital
investment and rate of return on this issue?
If BPL is proposed in my area I will be at all meetings raising the
mitigation technical and business issues.
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