Power Line communications & the amateur radio
ban BPL !
2002, Internet trials using the electricity power cabling system are
undertaken in the U.S.A. and Europe by private
and national electricity companies. These trials are know as Power Line Transmissions
(PLT), Power Line Communications (PLC) or Broadband
Power Line telecommunications (BPL) aka "courants porteurs en
ligne" in French (CPL).
uses the low and medium-voltage power lines like the ones installed
along our streets and displayed at right to distribute broadband
services on frequencies between 2 and 80 MHz. The signal is
broadband, meaning that it is spread over hundreds of kilohertz; in
other words these companies are parasiting our amateurs bands !
trials are in violation of the european directive about the
"electromagnetic compatibility" (ref. 92/31/EEC handling
the famous logo) that states that "everybody
may use frequencies at the condition to not disturb the other
users". However, it appears that these private or national
companies are far to respect this law.
this issue impacts broadcasters too that request a special
attention from ITU Radiocommunication Sector (ITU-R). Indeed Sub
Working Group (SWG) 6E1 expressed the view that
interference produced by systems employing BPL as well as by Industrial, Scientific and Medical (ISM)
equipment and short-range devices, would compromise broadcast
reception. BBC engineers for example described the interference as
varying between "annoying" and "a level
sufficient to make the broadcast completely unintelligible".
6E1 is of the opinion that "any increase in the amount of
noise due to these systems is unacceptable," said a
statement from the group's chairman to the chairman of Working Party
6E (WP 6E). "In particular, broadcast services should be
protected from unwanted emissions from PLT systems," the
panel asserted, "as these emissions are a byproduct of a
system that is not itself a user of the radio spectrum."
The panel recommended the formation of a group representing all
users of the radio spectrum "to coordinate development of
limits to be imposed on the radiation from these systems".
some companies gave up their BPL tests due to interference they were
unable to remove, other companies continue generating interference
on HF. In Austria for example, the Linz Power Company's BPL pilot
project created massive interference in the Red Cross service during
a disaster response drill in May 2003. The Austrian Amateur
Transmitter Federation (OVSV) asked the Government Ministry for
Commerce to halt these radio interferences.
the U.S.A. the Disaster Preparedness and Emergency Response
Association (DERA) called on the FCC to require impartial PBL field
testing as well as additional public comment and full and open
city purrs under BPLs
DERA concludes that "serious interference
to and disruption of critical emergency communications systems [...]
would almost certainly result from BPL implementation as currently
the Amateur Radio Research and Development Corporation (AMRAD) filed
additional test data with the FCC about interference caused by BPL
Their new data demonstrated that amateur operation in the
test neighborhood would cause many homes to lose their Internet
service. "At least an area out to a radius of 800m (0.51
miles) from the transmitting station could have their Internet
connection interrupted", ARMAD said. "Closer-in homes would
almost certainly have their Internet service interrupted".
its experiment AMRAD used the Potomac Electric Power Company system
test site, and a mid-1960s vintage home with unshielded interior
electrical wiring and overhead power lines. It resulted that at a
distance of 800m (0.51 miles), data transfer ceased in the face of a
100-W signal on 3980 kHz from a mobile transmitter. Adjacent to the
test property, data transfer ceased in all but one instance at a
transmitter power of just 4 W in the BPL operating band from 4 to 21
2004, the ARRL is conducting a complete and independent BPL
engineering study as well. Its results as well the comments of BPL
victims are regularly published in the columns of QST magazine.
forge your own opinion about theses interferences, I suggest you to
the next video to get an idea of the noise level generating by BPL
on amateurs bands. When BPL is activated you can no more work any station, neither local
DX. This is not acceptable ! You will also find a compilation of
videos recording these interferences on the ARRL
BPL interferences !
at Work in Austria (MPEG of 4.4 MB).
the weight of amateurs in this balance ?
joining the amateur radio community, broadcasters and emergency
services help us to fight
against these "BPL" companies. But it is still too early to say if this is
a good or a bad news for our hobby. Too much financial interests are
in balance and to save their economy (and gain votes) political
already demonstrated that they do not hesitate to hack FCC
commissioners who have no concept of the technology they are
supposed to be regulating. We all hope that the WP 6E's report will
be in favor of spectrum users without modifying our rights to use
amateur bands as we already observed in 432 MHz, 1.2 and 2.4 GHz
some times ago that were partly reassigned.
remind you that amateur
radio is more than an activity or a simple hobby, it is defined
as a service that we pay yearly. As such, if we can not take
advantage of this radiocommunication service, in some countries we have the right to require an
exploitation loss or at least to request the suppression of these
interferences at the responsible's charge.
until now neither our national representative ham associations (ARRL, RSGB,
ARC, RSGB, UBA, REF, etc) or the concerned IARU delegation can
oppose to this criminal practice.
radio associations have discussed about this problem in the offices of the
European Commission at Brussels in 2003, but without to get the slightest
action or result up to day, on the contrary... The European
Commission and well as FCC encourage the deployment of BPL networks
(without to forget Trans horizon radars interfering in amateur
bands, see this link) !
Sun Tzu wrote in his Art of War, "Know the enemy, know
yourself; in a thousand battles, a thousand victories". The most active ham association
fighting against this problem is actually ARRL on behalf of the
League's 155000 members who has gathered over 5000 complaints and
comments from the
amateur radio community. We all hope that this action will convince
one day ITU to prohibite BPL.
to such laxities and to lobbies that are standing by, early 2003 Hilary, alias G4JKS,
representing the UK Anti-BPL group gave up his fight against
administrations. Hopefully Peter Cochrane has resumed the fight and
wrote an article about BPL that his author ask us to publish as
often as possible on the Internet. Thanks to his fight and the new
ITU decision, the future of ham radio looks less noisy.
right technology for the right job
document is a reprint from a short article published on Silicon
website in which Peter
Cochrane reminded how can be hard the fight against
administrations even when hams rights are derided. Here are his
a decade now business plans have arrived on my desk, in increasing
numbers each year, but only a small percentage find their way to
commercial success. Remarkably I see very little correlation between
is, however, a major exception where the same plan seems to arrive
on my desk every year. Each time it is presented as revolutionary
and ground-breaking. But it is always the same technology and it is
always as flawed and as misconceived as the original I first saw a
reports often included to amplify the case are along the following
lines : XYZ Company is proud to report broadband internet trials are
underway using a ground-breaking technology that will revolutionise
radio, TV, cable TV, internet and data services to the home.
Existing electricity power cable can supply all of your digital
services at speeds up to 50 Mbits. Extensive laboratory trials have
proven this technology, and testing with customers is at an early
stage. If fully successful a commercial rollout is planned within
the next three months.
is then customary to include a CEO interview that says something
along the lines of : "All the obstacles have been overcome. The
technology is now proven, stable and economically viable, and we are
in a position to revolutionise the last mile. We also predict this
technology will see the demise of the telco in the next
companies usually keep their names secret in anticipation of further
announcements to be made later that year and the technical press
always seem convinced it is all true. But about 6-12 months after
the announcements the companies involved quietly say they are
ceasing trials and development because some alternative technology
has been discovered. It then goes very quiet and nothing more is
is the BPL status in Europe ?
Europe, some countries like Germany have fixed an
"acceptable RFI threshold" at 28 mV/m,
a value below which perturbations are considered as... "normal"
by the administration !
In fact this value is extremely
high, equivalent to a signal stronger than S-8. The receiver
module of a high-end transceiver is able to detect a signal
strength as weak as 0.15 mV/m
! You can imagine
what QRM theses signals can generate...
universities and private companies (e.g. Dortmund/Siemens, AG,
etc) did measurements and observed that during BPL/PLC trials
signals in HF bands reached between 13-17
dB above the threshold (NB 30). In other words these
signals blocked completely amateur receivers at
+17 dBm !
nothing change, you can consider to practice another hobby or
think working portable in the field, far from the power
The solution of using a very selective radio using mechanical
roofing filters that reject such a QRM and enhance the S/N ratio
but sometimes this solution will also raise the local noise.
In the worst case there is no solution. Sorry,
but it is the reality !
if nothing change, do ban BPL !
wouldn't find this so upsetting if it only happened once but to my
knowledge there have been dozens of false dawns. If only the people
involved would visit my office I could save them a small fortune. At
a modest estimate, over $200m has been expended to date and no one
has been successful in transmitting significant amounts of data over
power cables to the home.
can guarantee no one will get this technology to work as advertised.
It might be appealing and economically attractive but I'm afraid the
basic laws of physics cannot be sidelined. For anyone contemplating
the waste of another $5-30m here is my 'don't do it' shortlist :
Power cables employ low-grade plastic that is unfriendly to
high-frequency signals as the absorption per unit length is very
high. This alone precludes transmission of high-speed data over
Power cables are not physically symmetrical and are therefore very
effective antennas. They radiate energy from high-speed data signals
which becomes a source of interference for wireless services
including broadcast radio as well as emergency, maritime,
aeronautical, military and navigation services. By reciprocity they
also suck in energy from every local radio source which further
degrades data signals.
As signals propagate along cables they become weaker but the
switching transients from washings machines, refrigerators, vacuum
cleaners, electric drills, light switches and other appliances are
huge, do not decay at the same rate and swamp data signals
Switching transients on power grids with generators going on and off
line, dynamic load sharing, fault and maintenance work, all induces
massive transients that also swamp data signals.
Cable joints, transformers, power meters, the on/off nature of
electrical appliances and the topology of power grids create large
load changes and multiple signal reflection points. This creates a
dynamic echo environment where the transmitted signal is further
Real time communications of any kind - whether by telephone, radio
or TV - are taken out by the huge voltage transients inherent to
power lines and ultimately the data rates achievable for non-real
time are also very low.
Transformers and power meters require a workaround as they present
an absolute block to any high frequency signals.
aurora over New Zealand (46°S) pictured by Stephen
Voss on Septembre 8, 2002.
is a short disaster list that says this technology will not work.
And the real nail in the coffin ? Telephone and cables were designed
to carry far higher frequencies than 50 Hz power cables and in every
aspect offer superior performance for all data applications. And
more recently wireless technology is becoming so low cost and so
high performance that signal processing requirements for data over
power cables, even if it were possible, would be prohibitively
expensive in comparison.
many locations the power companies have installed optical fibre
along their power lines for telemetry related to the control of
power distribution. Because their data requirements are so meagre
huge amounts of bandwidth are available. So it does make sense for
wireless technology to be used at that end point, in a distribution
mode to attack the last mile.
all of this there are more than 20 power companies currently active
across Europe planning or conducting trials. The reported field
performance results are very poor, as expected! Installation costs
are higher than the telcos and cablecos. Yet they still seem
determined to become the biggest source of radio interference on the
the ultimate decider ? It looks as though the politicians will be
asked to decide between the power and wireless lobbies on the
legality of the interference levels.
to a widely held belief, all the technology necessary to transform
the local loop is to hand, and sporadic solutions such as data over
powerline are a bit of an economically driven red herring.
please, will the next candidate thinking of sending me another
business plan with a revolutionary technology that will exploit
power cables please employ someone who understands Maxwell's
equations, data transmission and holistic economics.
This column was compiled in a hotel lobby between meetings and
despatched via a Wi-Fi link that appeared without identification -
thanks to whoever decided to provide this charitable service.
can you do ? In the U.S.A. you can make a donation to ARRL to preserve
your rights. In other countries do preserve our bands in becoming
member of your national radio association. Do continue working in HF
bands too and complain to the police (with statement) and to your
national ham association each time that you observe a BPL trial in
violation of amateur rights. A passive attitude is in favour of BPL
companies and in this case do not be surprised if one day our bands
disappear, reassigned to other services.
addition, each time that you read an article about BPL in a magazine
and that it forgot to speak about interference generated by these
trials, write to the editor, explaining what are the side effects of these
transmissions on HF bands and specially on radio amateurs activities,
emergency services, broadcast listenings and army transmissions.
action now ! Publish as often as
possible this page on the Internet and discuss about BPL with all
concerned actors. All
the amateur and broadcaster community will thank you.
Working Party 6E
measurement in Europe, CE-Mag
join Anti-BPL Chorus, ARRL
is a Pandora's Box, ARRL
and Amateur Radio, ARRL
of RFI caused by BPL, ARRL
Powerline Communications Systems,
Field Strength Meter (in kit)
(Info & forum sur le Courant Porteur en Ligne)
ça marche (CPL)