Hi,

Do you remember the problem caused by broadcasting tests via the power line
?
A lot of radio amateur have to support the RFI causes by these tests
everywhere in Europe.
All hope is not lost.
ITU officially recognized this was unacceptable...

http://www.arrl.org/news/stories/2003/10/09/1/?nc=1


Thierry
ON4SKY, LX3SKY
http://www.astrosurf.com/lombry/menu-qsl/.htm


"Thierry" see my website a écrit dans le message de
...

Internet trials using the electricity power cabling sytem are currently
undertaken in the USA and european countries like
Austria, Belgium, France, Germany, Luxembourg and Switzerland
among others by private and national electricity companies.
Such trials are in violation of the european directive about the
"electromagnetic compatibility" (ref. 92/31/EEC handling the famous CE
logo)
that states that "everybody has the right to use the frequencies at the
condition to not bother the other users". However, it appears that these
private or national companies are far to respect this law.

Amateur radio is a service that we pay yearly and as such, if we can not
practice this activity we should have the right to require an exploitation
losse.

Unfortunately neither our national representative ham associations (DARC,
UBA, REF, RSGB, etc) nor the concerned IARU delegation can oppose to this
criminal practice.

Ham associations have discussed about this problem in the offices of the
European Commission at Brussels, but without to get the slightest action
or
result up to day...
Confronted to such laxities and to lobbies that are standing by, recently
Hilary, alias G4JKS gave up his fight against administrations, hence the
publication of this article that the author ask us to publish as often as
possible on the Internet.

The right technology for the right job, by Peter Cochrane,
http://www.silicon.com/petercochrane

This document is a reprint from a short article published on Silicon
website
in which the author reminded how can be hard the fight against
administrations even when hams rights are derided.
Here are his commentaries.

For 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 plans.

There 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 decade ago.
News 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.
It 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 decade..."

Partner 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 heard.
I 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.

I 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 significant distances.
- 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 corrupted.
- 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.

This 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 50Hz 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.

In 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.
Despite 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 planet.

And 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.

Contrary 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.

So 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.