Subject: [NEXTEL-1] The BPL Dilemma

From: [email-masked]
Date: Tue, 27 Apr 2004 12:02:14 -0400

The BPL Dilemma

Because of the importance of the
Broadband over Power Lines (BPL)
issue, “FM” columnist Gary Pearce,
KN4AQ, devotes his space this time to the
investigation of a BPL test site and the
surrounding area. He will be back in the
next issue of CQ VHF with his regular
column material. —N6CL
Since last fall, I’ve been up to my
eyeballs in BPL—Broadband over
Power Lines—and its effect on
amateur radio. If you’re up on current TV
culture, you can call it “HF Eye for the FM
Guy.” Our area has been “lucky” enough
to host one of the few BPL trials, courtesy
of my local power company, Progress
Energy, and equipment vendor Amperion.
Several other local hams and I have been
very busy learning about BPL, measuring
the effects, working with the power company
and vendor, and relaying what we’ve
learned to our fellow hams. I thought you
might be interested in a fairly intimate
review of what I’ve been going through.
It’s not nearly over, but the deadline
looms. They say that writers should write
about what they know, and right now this
is what I know. This will be a deep breath
for me, and maybe some catch-up for you.

Here we go.

Here we stop. I suppose I need to make
sure you know what BPL is. It certainly
has been the buzz of ham radio this winter,
but there’s a lot of misinformation
about it. I’m always running into hams
who have heard the initials but they only
have a fuzzy idea of the basics, which is
not surprising. For 99.9% of hams, BPL is
still academic. They haven’t encountered
it yet. I will provide a quick tutorial.
The basics of BPL are simple. It is a
method of delivering high-speed internet
to homes and small businesses using the
local power lines that crisscross neighborhoods
either overhead or underground.
This is a brilliantly obvious idea
(“the wires are already there!”) that was
delayed because the AC power grid is a
really noisy, crappy signal-delivery
medium for anything above 60 Hz. The
march of technology, however, is making
it feasible. It is the third method of
doing that, following DSL (Digital
Subscriber Line) on the phone lines and
cable TV (nobody’s come up with a cute
name or acronym for broadband over
cable TV; they just call it “cable”).
Actually, wide-area wireless using
microwave frequencies is really the
“third” method of delivery, but it doesn’t
seem to be lighting any fires in the imaginations
of the industry press, the public,
or the FCC, the way BPL is (too bad). I’m
told that it’s a better system.

This Little Flaw...

BPL has lit fires. The FCC commissioners
are mostly agog over it, as they
love the idea of competition for phones
and cable and the possibility of serving
rural citizens (“the wires are already
there...”). A little flaw exists, though.
BPL puts radio signals on the wires in the
HF and lower VHF spectrum, from 2 to
80 MHz, according to most vendors.
Mull over the following phrase for a second:
“puts radio signals on wires.” What
could we be describing? You, in the
back...? That’s right! Radio! Cable and
DSL do the same thing, but generally at
lower frequencies (below 3 MHz) and in
either a shielded cable or a balanced pair
of wires that don’t radiate (much). The
power lines! Haven’t you ever looked up
at that magnificent infrastructure, long
wires strung between tall towers, and
thought what a great antenna system it
would be?

Well, let’s not go overboard. They
won’t put BPL on those big transmission
towers. Those generally are carrying
fiber-optic cable already, thanks to forward-
thinking engineers a decade or two
ago. BPL goes on the local wiring, from
the substation to your home or business,
across your back yard or beneath your

The BPL Dilemma
Hams claim Broadband over Power Lines will interfere with their
on-the-air operations. The utility companies claim not. Read how they
are both right . . . sort of.
By Gary Pearce,* KN4AQ
*116 Waterfall Court, Cary, NC 27513
e-mail: <[email-masked])>
The BPL “injector” on this power pole
feeds the RF energy onto the power line.

Reprinted with permission from CQ VHF Magazine, Spring 2004 issue.
Copyright CQ Communications 2004
front yard. It doesn’t radiate like a kilowatt into a rhombic, but it
does radiate, and it’s regulated by Part 15. How it radiates, and how
well, will come out as our story unfolds.

BPL appeared on the collective amateur radio radar screen in the U.S.
some time last year. The more astute among us saw it long before then. I
probably read Dave Sumner, K1ZZ’s October 2002 QST editorial entitled
“Radio Smog,” which talked about general pollution (the physical kind in
the air and water) and good old power-line noise, and introduced the
concept of BPL . . . gently, so as not to create mass panic. He didn’t
call it BPL back then. In 2002 the initials BPL only meant Brass
Pounder’s League, an exalted position that a CW operator can attain for
passing lots of message traffic. If the editorial made any impression on
me, it was probably something like “Sure .  . . no way that’s ever going
to happen.”

It was already happening in Europe and Asia, and in early 2003 power
companies around the U.S. were building trial areas to see what this was
all about. In April, the FCC issued a Notice of Inquiry, asking if Part
15 needed to be modified to accommodate BPL. Thousands of hams
responded. I was late to the party, but I finally got on the FCC website
and said something about the need to pay attention to the interference
problem.

Eye Opener Number 1

The ARRL’s Lab Manager, Ed Hare, W1RFI, was on the case early. Last
summer, he equipped a car with radios, a shortened dipole, and a video
camera. He visited some of the trial areas.  The video is available for
download on the ARRL web page (www.arrl.org) and plays on all the usual
media players on your computer. I finally got around to downloading it,
and suddenly I was very interested in BPL. To a ham, it was
frightening.  We’ve been battling noise on the ham bands since the
beginning.  Heck, a lot of the noise was there long before we had
receivers to detect it. Over the decades we’ve created a lot more of our
own. Power-line noise is a familiar ham complaint.  Computers and
clock/processor-based devices have escalated the man-made RF noise
problem since the late ’80s. What I saw on Ed’s video took things to a
new level. Heck again . . . it skipped a level or ten. This was an
exponential leap in interference.  Ed recorded crackling and clattering
with S-9 signals that extended over hundreds of kilohertz. You can see
him spinning the dial on his TS-440, flying across the spectrum, and the
noise never changes. I played this video at a radio club meeting and
jaws dropped. It seemed like the future of amateur radio dropped. Then
anger rose. The FCC Notice of Inquiry drew more than 5000 comments and
reply comments, mostly from angry hams, but some from a BPL industry
claiming that there was no interference problem at all!

Then it got personal. A short article in the business section of the
local newspaper and a TV news report or two announced that Progress
Energy, the power company for much of eastern North Carolina and a big
part of Florida, had quietly been testing BPL almost in my back yard.
Actually, it was on the other side of town, where a small test occurred
over a few blocks in a new subdivision. In a review to the FCC, the
utility noted that there were “no reports of interference.” Well, duh!
Nobody knew about it. No hams lived in the new, severely
antennarestricted neighborhood. Even if a ham had heard it, the person
wouldn’t know what it was, so why would the power company be called? It
didn’t sound like power-line noise (more on what it sounded like in a
minute).

As Public Information Officer for the local club and ARES group, I began
contacting the press that carried the story, and I wrote some bulletins
for quick distribution on area club mailing lists. Area hams reacted by
writing and calling Progress Energy to protest the development of this
technology—technology we really didn’t know much about, except that it
could fill the ham bands with garbage.

A few local hams did more than just file general protests.

This is the BPL hardware inside the ground-mounted pedestal.  Bill
Godwin; Will Roberts, AA4NC; Tom Brown, N4TAB; Frank Lynch, W4FAL; and
Amperion’s Garrett Durling measure BPL signal levels from the
ground-mounted pedestal.
(Continued on page 80)
technical community is small enough
such that hams know engineers and engineering
managers in just about every
company around. Some of them made
discrete inquiries to contacts at Progress
Energy. The power company realized
that they needed to talk to hams, but they
couldn’t talk to all of them at once. They
first reached out to the ARES Emergency
Coordinator for the county, Tom Brown,
N4TAB. Tom is an engineer at a small
company doing equipment development
for several government agencies. Then
they called me, and a third ham, Frank
Lynch, W4FAL. Frank is an ARRL
Technical Specialist, and an RF engineer
for Nortel, the giant telecommunications
company. Last October, the three of us
discussed ham radio and BPL with Bill
Godwin, an engineer, who became our
contact at Progress Energy.

Bill visited my shack, and I showed
him some ham radio basics. We listened
to weak signals and talked about interference
and notching.

Eye Opener Number 2

We learned from Bill that the Phase I
trial, concluded earlier in the summer,
had been successful from the company’s
point of view. The equipment, supplied
by Amperion, worked well and provided
throughput beyond expectations. We also
learned that although the test was over,
the equipment was still in place and some
of it was still turned on. Tom and I both
have HF-equipped mobiles, and we went
to listen.

A ham at Progress Energy told me to
listen on 10 meters along a certain stretch
of road near the trial neighborhood. As I
approached the site, I wondered what I
was going to hear. Ed Hare’s video
showed a different company’s technology
with a different RF “signature” at each
trial site, so I didn’t know quite what to
expect. I cranked up the volume and paid
careful attention to every pop and squawk
from the speaker as I tuned up and down
the band. Ten meters was quiet that day,
with only a few ham signals here and there.
Then I heard it, faintly at first, but
quickly getting stronger as I drove. This
“signature,” from the Amperion system
using something called the “DS-2 Chip
Set,” was both extremely familiar and yet
like nothing I had ever heard before. It
was familiar because it was just carriers
—nearly pure CW carriers, although
some had a little tick-tick-tick clock
sound on them. I was in SSB mode, so
each carrier appeared as a note or tone.
What’s different was how many of them
there were, how close together they were,
and how much of the band they occupied.
A lot. Very. And All.

This was BPL 101 for me, the beginning
of the education. The signal quickly
peaked at S-9 as I pulled under the
active overhead power line. I pulled off
the road and analyzed it. The individual
carriers were about 1 kHz apart, so as I
tuned up the band, I could hear beat notes
from two carriers at once. There was
always a BPL signal in the speaker, and
they all were about the same signal
strength. I tuned, and I tuned across the
whole 10 meter band, and down below
into the CB band. The BPL covered it all.
The signal did fade relatively quickly
as I drove away from the power line, fading
to almost nothing a few hundred feet
away. The overhead line was on the main
road, but the neighborhood into which I
was driving had all underground power.
I didn’t know if the 10-meter signal fed
the whole neighborhood, or even if there
was anything left turned on away from
that overhead line. Still, I could imagine
a ham with a dipole or a beam in the air
somewhere nearby. They’d get a much
KN4AQ’s mobile transmits on 29.6 MHz while under the active power line.

The quick transmit test was inconclusive. However, AMRAD’s tests show
problems when amateur radio operators transmit.

Tom Brown, N4TAB, listens on 24 MHz at Roland Erickson, WAØAFW’s home
near the second trial area. The signal was weak, but audible on Roland’s
attic-mounted dipole, about a half mile from the BPL site.

BPL Dilemma (from page 9)

stronger signal than I did with my Outbacker mobile antenna.  Watching
Ed Hare’s tape was powerful. My hearing these “invader” signals in the
10-meter band was even stronger.  Progress Energy planned a Phase II
trial to begin in early 2004, and Bill Godwin promised that we would be
invited to see it. This one would be bigger. It would have a new
generation of technology, but mostly it would be a marketing test.
Would people want this stuff? Going head to head with cable and DSL,
would there be any advantages? Meanwhile, I learned more. The BPL
industry was still denying that there was any interference, while the
ARRL was showing that there was.  Hams were fuming on message boards,
plotting more revenge than strategy. On websites such as DSL Reports, a
more balanced story was told, but non-hams who were writing replies
called us old men practicing a dying art that should well be sacrificed
for the greater good. That would be downloading music from Kazaa,
sitting in chat-rooms, playing on-line video games, and maybe getting a
little work done, right?

In early January we got the call. Thursday, January 15th, was our day.
The location was kept secret. Tom, Frank, and I headed south from
Raleigh, North Carolina early on a chilly morning (for you guys up
north, it was a balmy summer day). We met Bill Godwin, several other
Progress Energy engineers (some hams included), and Garrett Durling, an
engineer Amperion had flown down just to meet with us. We drove out to
an isolated neighborhood of brand-new homes in an otherwise rural area,
and Garrett described the system.

Because this was a trial area, the data was piped in on a 5-GHz dish
mounted on a power pole, and then fed into the BPL equipment to run down
an overhead line along the highway for about a half mile. Then the data
was pulled off, and an 802.11b Wi-Fi system bridged the highway and
brought it into the neighborhood, where it was put back on the buried
power line as BPL.  Every 2000 feet or so the power line came up out of
the ground to run through a “repeater” in a green cabinet on the
ground.  Some BPL systems bring data right into the home using the power
line. You plug a stand-alone box into the wall outlet and connect an
Ethernet line between a port on the box and your computer.  The
providers promote the fact that you can plug this box into “any outlet
in town” and get high-speed internet. Amperion does it a little
differently. They place 802.11 Wi-Fi nodes around the neighborhood, and
you hook up with a Wi-Fi card in your computer or other wireless device,
such as a Palm.

All that was pretty cool, but we were interested in spectrum use. Time
for school: BPL 201. The following description applies to the Amperion
system, and not necessarily to other BPL technologies.  The data goes on
the power line using two blocks of RF spectrum, one for upstream and one
for downstream. The upstream block is 2.5 MHz wide, and the downstream
block is 3.5 MHz wide. Within each of those spectrum blocks are the
carriers I heard—thousands of them, completely filling the block. The
blocks can be anywhere between 2 and 50 MHz, and can be as close
together as 100 kHz or as far apart as opposite ends of the spectrum.
Amperion tends to use frequencies above 6 MHz and below 31 MHz. At each
repeater the data moves to a new set of carriers on two new blocks of
spectrum. The spectrum blocks can’t be reused for several power-line
legs, about a mile, so they don’t hear each other.

This system used 25- and 28-MHz spectrum for the overhead line, just
like the Phase I system I’d heard in the fall. Sure enough, there it was
when we tuned in. Once again, the signal was S-9 when we drove under the
line and faded a few hundred feet away. The underground legs used other
HF spectrum. I heard signals at 7, 10, 11, 15, and 18 MHz, crossing ham
and shortwave broadcast bands and everything in between. One put a fat
beat note on WWV while listening in AM mode. The signals on the buried
line segments could only be heard while near the above-ground pedestals;
about a hundred feet away was the limit. Keep in mind that this was with
a mobile antenna. How much more would a home station with a bigger
antenna hear?  We don’t know, but more than the mobile, for sure. Once
again, there were no hams living in the neighborhood. We called one ham
we knew who lived nearby, a little over a half-mile from the overhead
line. He tuned the 10-meter band and the signal was clear, if not really
strong.

A group called AMRAD (Amateur Radio Research and Development
Corporation) had published details of an extensive test of reverse
interference—ham radio shutting down BPL. They had a lot of, well,
success, I suppose, causing problems.  Low-power signals totally blanked
data throughput in some cases, and higher power always did. We tried a
brief test.  We didn’t have a computer connection, but Garrett called
his NOC (Network Operations Center) and had them loop some data through
the system. We keyed up on 29.6 FM with 5 watts, right under the wire
that was using 28 MHz, and sure enough, it stopped. It started up again
as soon as we unkeyed. Then we tried it with 100 watts, maybe hoping for
a longer lasting effect.  We caused a hiccup, but didn’t shut it down.
That’s all the time we had for a transmit test. Don’t read too much into
the results.

The Solution!

We learned the source of our salvation, the solution to our
worries. The system is frequency agile. If there’s an interference
problem, the NOC can move the carriers around in the
spectrum and notch out some of them. I heard echoes of this
when I read the NPRM released in late February; that’s just
what the FCC is proposing they’ll have to do. How fortunate
they already can. This is where the industry hangs its hat on the
question of interference to hams. They can move . . . except not
today. During our visit, I asked them to move this interference
off the 10-meter band (and the other block of spectrum off the
Amperion’s Phillip Hunt shows FCC Chairman Michael Powell the hardware
inside the ground-mounted pedestal.
12-meter band). No can do. The NOC is busy provisioning another system.
It is still on the 10-meter band as I write this column, almost 60 days
later.

I’m getting ahead of myself. Our next job was to see just how
significant the interference problem was. The FCC database and Street
Atlas mapping program came together to help me plot all the hams in the
area. One by one, from a zip code delimited list, the map filled in.
There are lots of hams on the south end of Raleigh and the suburb of
Garner, a bit north of the trial site.  Fewer are out here in the
country, but there were three hams within a one-mile radius and four
more within a two-mile radius. I contacted them, found out who was
active, who wasn’t, and who heard the signal. Tom and I visited several
of them to verify their reception. The result: Hams with simple dipole
antennas clearly heard the 10-meter signal from the overhead lines up to
a mile away. A ham with a large beam on an 80-foot tower heard it at a
mile and a half away.

Everyone in town thought they heard it. BPL has become the new
intermod—the catchall name for any squeak and squawk we think we
shouldn’t expect from a speaker.

We learned of a second trial area five miles to the west that they
hadn’t told us about. It was a similar setup, with an overhead line on
12 and 10 meters and a neighborhood with underground wiring. I plotted
the locations of those hams, with similar results. There were a few more
hams in the zone, as this was closer to a town. They heard about the
same level of signals.  While all this was happening, the FCC released
its Notice of Proposed Rulemaking (NPRM) for modifying Part 15. It was a
good-news/bad-news deal. The good news: It prominently mentions the
interference problem and proposes some steps that would “mitigate” it.
The bad news: They think these steps will work. The steps include
creating a database so anyone experiencing interference can look up and
find the location and frequencies used by nearby BPL, and the “adaptive
interference mitigation techniques” such as frequency agility and
shutdown capability by remote control that I mentioned earlier.
The comment period on the NPRM will have closed by the time you read
this, but the reply comment period should still be open.

Customer Service?

What this sounds like to me is ham radio by customer service.
Congratulations on passing your exam. Here’s your CSCE and a card with
the phone number of your local utility. Give them a call and they’ll try
to have some bands clear of interference at your house by the time your
ticket arrives. However, call right away. . . . They’re a little backed
up, and they’re running out of spectrum.

Running out of spectrum? Well, I’m not the ultimate authority,
but I did a little noodling and tried to put all the puzzle
pieces together. They didn’t fit.

I’ll make the assumption that BPL can’t operate without using ham
frequencies. If it could, they’d just do it, but the interference zone
from an overhead wire is at least a mile in diameter.  In just about any
mile-diameter circle there is an active ham, and that’s in rural
territory! The ham population is much denser in real suburbs or urban
areas. How are they going to put up BPL and not interfere with hams, no
matter how they can slice and dice their spectrum? It’s a question I’ll
be posing to our power company after I file this story. I wish I could
give you the company’s answer, if they have one, and probably they
will.  Even if they have a good answer, there’s another problem—mobiles.
How do you mitigate interference to a mobile?  This agility solution
works for most of the other HF services, the ones which use specific
channels that can be deleted from the carriers on the wire. Ham radio is
different. We roam our spectrum, operating on whatever frequencies we
choose. We look for weak signals, so just because BPL is weak doesn’t
mean it doesn’t interfere.

The rules prohibit Part 15 devices from causing harmful interference
to licensed services, and I expect future arguments to
turn on the definition of “harmful”:
§97.3(a) (23) Harmful interference. Interference which endangers the
functioning of a radionavigation service or of other safety services
or seriously degrades, obstructs or repeatedly interrupts a
radiocommunication
service operating in accordance with the Radio

Regulations.

They’re going to say that their weak signals aren’t harmful.
We’re going to say they are.

Meet the Commish

Just as this episode was coming to a close, I got word that FCC Chairman
Michael Powell was coming to town to see the BPL trial, an event open to
the press. Tom, Frank, and I (and a few other interested hams) hastily
rearranged our schedules to be present.

We arrived at the home of a trial BPL subscriber about an hour before
Powell was scheduled to arrive. I introduced myself to the top BPL guy
at Progress Energy, Matt Oja, and the CEO of Amperion, Phillip Hunt.
There wasn’t much happening yet, so we had an interesting discussion. I
had realized long ago that this is serious, big business. They needed to
know we hams are just as serious.

Powell arrived, along with two other top FCC officials,
Robert Pepper (Chief, Policy Development) and Chris Libertelli
(Senior Legal Advisor). I got to talk with the chairman for
a few seconds while the Progress Energy people were getting
their demo ready. He saw my callsign badge and said, “Hey,
FCC Chairman Michael Powell uses a computer receiving internet data via
BPL.
KN4AQ, good to meet you!” I told him
that we thought the interference problems
were worse than what was being
described by the FCC and the industry,
to the point where we didn’t think they
could be solved.

I talked at some greater length with
Robert Pepper, who approached me after
I talked with Powell. Then, while I
observed the Progress Energy presentation,
Chris Libertelli stayed outside to
talk with the rest of the assembled hams.
He said he understood that one of our
main concerns was enforcement, should
BPL cause harmful interference.
Is the Game Fixed?

Something doesn’t add up. The FCC
admits that BPL will not be allowed to
interfere with ham radio or other licensed
services, per Part 15. They remain bullish
on the technology, however. They
have all their chips on the ability to mitigate
interference. We are an inconvenient
technicality.

I’m not expecting any surprises from
the NPRM. Hams will say it won’t work.
The industry will say it will work. The
NPRM should become a Report and
Order with little change, and the BPL
industry will be off with a pat on the back
from the FCC.

Then, if I’m right, the complaints will
begin. How will they be handled? How
can they be? Will the FCC really tell any
utility to turn off its BPL in an affected
ham’s area (about a square mile)? Will
they address mobile problems?
A lot of hams are saying the game is
fixed and the deck is stacked. Time will
tell. One way or another, I’ll be very
happy to get back to concentrating on FM
. . . and I’m keeping the phone number of
my local utility handy.

Note: There is an MP3 file with a sample
of what Amperion’s BPL signals
sound like on the air, narrated by yours
truly.

It’s on the web at <http//www.cqvhf.com/BPL.html>. _

BPL Comment Deadline May 3

The FCC Notice of Proposed Rule Making
on BPL, ET Docket 04-37, was published in
the Federal Register on March 17. Comments
are due by May 3, with reply comments due
by June 1. We urge you to learn all you can
from articles here and elsewhere, read the
NPRM, and file comments via the FCC’s
Electronic Comment Filing System, or
ECFS, at <http://gullfoss2.fcc.gov/ecfs/
Upload/>.

http://www.cq-vhf.com/BPL%20VHF.pdf
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