Serious Danger to Shortwave Bands in DL
Toby Deinhardt (DJ7MGQ)
on
April 6, 2001
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The below is a description of save-shortwave at http://www.egroups.de/
On March 30 the German Government signed an act that allows the generation of noise levels on all frequencies up to 30 MHz that will make most use of shortwave impossible. We expect other european countries to follow.
In worst case this law will allow S9+ noise levels on all shortwave bands 24 hours a day 365 day a year.
Providers of "Powerline Communications" (PLC / PLT) recently started offering their services to the public. PLC / PLT will be the first service to create the described noise levels.
We are afraid that in the near future nobody in europe will be able to get uncensored information from outside his own country, shortwave amateur-radio will become impossible at least in Europe
Please help us to spread this information.
(a few comments:
- "the German Government signed"
is not 100% correct. The German version
of the senate passed 3 bills, meaning
that these will become law.
- "nobody in europe will be able to get
uncensored information">
I rather doubt that non-shortwave sources
of information, eg. newspapaers, will be
censored.
- More information (auf Deutsch can be found
at:
Störfeldstärken durch Powerline Communication im 230V-Netz>
http://www.europoint.com/down/emv2000.pdf
Folgen großflächigen PLC-Einsatzes>
http://bilbo.e-technik.tu-ilmenau.de/plc/plc.html
NB30 und Rundfunkempfang (vom Institut für Rundfunktechnik)>
http://www.qsl.net/dh7uaf/irt.pdf
Studienergebnisse zu EMV-Problemen>
http://www.regtp.de/tech_reg_tele/start/in_06-03-02-03-00_m/index.html
Zweite Abfrage zu "Powerline Communications" - Schreiben des RTA an die
RegTP vom 15.02.2001>
http://www.darc.de/aktuell/voinfo/vor011502.html
Arbeitsgemeinschaft Zukunft Amateurfunkdienst e.V.>
http://www.agz-ev.de/statements/pdf/regtp_plc_zweite_abfrage.pdf
PLC stört Rundfunk und andere Funkdienste>
http://www.muenster.de/~dl5qe/plc002.htm
PLC – nicht empfehlenswert>
http://www.darc.de/aktuell/04112000.html
vy 73 de dj7mgq)
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Serious Danger to Shortwave Bands in DL
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by DJ7MGQ on April 6, 2001
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BTW: here is an english language article http://www.darc.de/referate/ausland/aktuell/actual.html
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Serious Danger to Shortwave Bands in DL
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by DJ7MGQ on April 7, 2001
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To see what NB 30 (the bad part of the new regulations) allows please goto
http://www.egroups.de/files/save-shortwave/NB30FS.html
For brief rundown of the ham frequencies in DL goto
http://www.egroups.de/files/save-shortwave/merkblatt_en.html
Both of the above include english.
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Serious Danger to Shortwave Bands in DL
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by I2VFB on April 8, 2001
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Toby,
Would you please elaborate a little about this noisy new service ? How will it cause interference ?
Thanks, Francesco Basta, Monza (Italy)
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RE: Serious Danger to Shortwave Bands in DL
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by DJ7MGQ on April 9, 2001
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If you take a look at http://www.egroups.de/files/save-shortwave/NB30FS.html you can see the noise levels allowed by the new regulations. The rest, to put it in a nut shell is, powerlines are not designed for high frequency signals. To deliver a signal to the end user, this means that fairly high power levels are needed, and all the wiring from the feed point will act as antennas. Because high data transfer rates are to be offered, this means that PLC will use a large part of the spectrum below 30MHz and there studies for even higher bandwidths.
I would also suggest looking at http://www.darc.de/referate/ausland/download/darc-plc-paper.html , http://www.darc.de/referate/ausland/aktuell/PLC-inGermany-3-2001.pdf and http://www.darc.de/referate/ausland/aktuell/plc-legal.html . These documents are in english.
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PLC not recommended
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by DJ7MGQ on April 9, 2001
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03.10.2000
To all radioamateurs
RTA and DARC e.V. present this document as a contribution to inform the amateur radio community on the issue of PLC and as discussion material to be used in public relations efforts. Latest developments are taken into account.
The paper is a common effort of DF7VX, DJ6AN, DJ1ZB, Mrs Volmer, DL2CH, DJ8CY, DF5DP, DF4JI, DL9MH and DF9IC and of the member societies of the RTA.
Translation by ON4WF.
PLC – not recommended
1. PLC – How it works
PLC (PLT) is the acronym for Power Line (Tele) Communication. Intended is to implement telephony and high rate Internet datatransmission on the existing 230 V (50 Hz) power grid in the users home, as well as Data, Audio and Video transmission from outlet to outlet inside a building or dwelling place (domotics). The datatransmission occurs broadband on radio frequencies up to 30 MHz. Not intended for the transmission of radiowaves on frequencies up to 30 MHz, the mains act as radiating antennas. PLC operators are (or will be) subject to radiation limits. Legal reference is the not yet enforced NB 30 frequency management norm. Most PLC systems will not be up to these constraints and consequently exceed the limits.
It has to be noted, that several existing appliances such as babyphones, garagedoor openers and heating controls are also mains channelled PLC applications. Using very low frequencies instead of high frequencies, these applications are free from undermentioned shortcomings and appropriate for domestic use.
2. PLC disturbs short wave radio services
PLC short wave frequencies have since long been allocated to various radio services such as broadcasting, air and maritime communications, fixed and mobile radio services, military, security services, radioastronomy, etc. not to forget the amateur radio service. Even with radiation limited to the NB30 norm, short wave reception is considerably disturbed because the receiving antennas cannot be set up far enough from the mains. Medium waves broadcasting and other frequencies can also be disturbed. These disturbances can endanger the very existence of some radio services, such as short wave broadcasting and the worldwide amateur radio service.
3. Short wave radio disturbs PLC
Widely distributed power lines, acting as antennas, not only produce strong disturbing radiation but also collect all kinds of high frequency signals, resulting in high noise levels on the mains. Regulations provide no legal protection of PLC against disturbances. High noise levels can considerably lower the datarate and even disrupt transmission, preventing the service provider to furnish the garanteed datarate. PLC's immunity from disturbances is determined by the degree of protection built in the system itself. High immunity calls for a corresponding degree of protection measures, detrimental to the effective transmission capacity (datarate).
4. PLC can disturb other electronic devices
Since PLC signals, travelling on the power mains (230V - 50 Hz), directly access all mains fed devices, it is likely that a multitude of electronic devices will suffer interference, in particular entertainment and medical equipment in hospitals and consulting rooms. Most such devices have no special protection against PLC signals and are exposed to disturbance. In critical locations, such as intensive care services, human lives can be endangered. For safety's sake, each device will then need appropriate and expensive protection measures.
5. PLC is unsure
A paper on PLC, published by the society for science and technology of the Dresden Technical University, concludes that PLC efficiency suffers from the mains “impedance unstability” resulting from totally uncontrolable consumer on- and off-switching.
6. Right now, PLC is an outdated system
Electronic devices and modulation systems used for PLC draw on the latest technical developments in order to assure proper datatransmission on since long heavily polluted power wires. Compared to alternative techniques, the PLC datatransmission system, with a datarate limited to some 2 MB/second, does not even match ADSL (datatransmission on telephone wires at 8 MB/second) commonly presented to the general public. Amateur radio operators consider cable TV datatransmission a valuable alternative. ADSL also, provided that nearby amateur radio frequencies are protected by adequate filtering. These amateur radio reserves do not in any case extend to future alternative solutions such as fiberglas cable, microwave systems for small cells or the oncoming UMTS mobile system.
7. PLC is exposed to eavesdropping and malicious jamming
Like all radio signals, PLC can be intercepted and copied by anybody in the home or building. Therefore providers will take steps to secure PLC transmissions. Protection efficiency will depend upon securing measures, which ordinary end users cannot control. Users have no means to evaluate risks and cannot decide when to protect themselves. Since no connection is needed, eavesdropping is easy. Considering the expected numbers of users, illegal copying will rise to unheard of summits, and the forseeable lack of data security is extremely high. Since radio transmissions are exposed to interference, a user terminal can easily be disturbed by a nearby jammer, even with low power.
8. PLC interference breaks the freedom of information
PLC can totally disrupt short wave broadcast reception cherished by our foreign fellow-citizens, as well as medium wave broadcasting and other radio services, such as the international Amateur Radio service. This is an infringement of Article 10 of the European Convention on Human Rights (fundamental right to active and passive freedom of information) since access to not otherwise accessible information is denied. On the other hand, practically all information and services offered by PLC are accessible through other and at least equally valuable or better techniques.
9. PLC raises completely new legal issues
Problems related to the delivery of data by power companies to end users at the limit of the property or at the power outlet in house (as well as the technical and legal liability for the PLC connection and for the content of the PLC exchange), refusal of citizens to accept the presence of PLC data on their property, endangered freedom of information and lack of data safety as well as questions about the applicable legislation on electromagnetic compatibility (EMC) in case of interference, raise legal issues and endanger good neighbourhood.
10. PLC is not economically justified
Compared to other data transmission systems, PLC is a waste of economical resources. In the United Kingdom, the promotors of PLC withdraw soon after some initial enthousiasm. Taking into account the cost and the return ratio of PLC, it is forseeable that market mechanisms, once coverage becomes widespread, will confirm likely negative results. The limited range of PLC restricts the implementation to densely populated areas, where a multitude of users have to share a limited bandwidth.
11. PLC's efficiency does not meet the growing need of quick datatransmission
In distributed workplaces, professional computers nowadays show datatransmission rates of 100 Mbit/s. Industry prepares a norm based on 10 Gbit/s. Professionals agree that datatransmission to PC terminals follows the law of Moore, stating a two-fold increase of processing speed every 15 to 18 months. Personal computers of individual users will benefit of this technical development. Evidently, the projected PLC datarates of some 2 Mbit/s from provider to user will be outdated once widely spread. Shareholders of PLC promoting concerns should be aware of this when making decisions on the stock exchange.
12. Opposition
Opponents expressed their concern in a public hearing on frequency management presented by the german regulatory authority, more precisely about the norm NB 30. Significant is the negative position taken up by representatives of safety services, military, broadcasting, internationally renown manufacturers of short wave equipment and audio and HF measuring instruments, other radio services and short wave users such as radioastronomy.
13. Their experimental service threatened to death, the radio amateurs strongly oppose PLC
Using very sensitive receivers for their experimental service, radio amateurs are especially concerned. In an official hearing of the german ministry of trade, they firmly expressed their opposition to PLC. Amateur radio operators have observed pilot projects, measured and made available the interfering signals. The DARC has participated as observer to tests performed by the spectrum surveillance service. Radio amateurs have taken part in press conferences of future PLC providers and their questions have given rise to considerable uncertainty. Radio amateurs, primarily concerned, have produced press releases against PLC, participated to TV programmes, given interviews to local newspapers and alerted the European and the German members of Parliament. The DARC has exposed the issue to EUROCOM (European Union workgroup of the International Amateur Radio Union) as well as to the IARU conference and to the radio amateur community throughout Europe and worldwide. Common action of European amateur radio societies has been developed. Outside of Europe, progress was noted in New Zealand and in Australia where radio amateurs showed considerable awareness and concern about these critical developments.
Karl Erhard Vögele, DK9HU
President DARC e.V.
This is the document at http://www.darc.de/referate/ausland/download/darc-plc-paper.html
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Why powerline failed in the UK
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by DJ7MGQ on April 9, 2001
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From the BBC:
http://news.bbc.co.uk/hi/english/sci/tech/newsid_101000/101787.stm#top
Streetlamps dim hopes for Internet highway
Information on the interent could have, unwittingly, been broadcast by streetlamps
A bright idea to turn the electricity mains into an information highway has hit an unexpected obstacle - streetlamps.
Technicians testing the system in Manchester found lights using the same power supply as potential Internet customers became aerials, broadcasting downloaded data as high-frequency radio waves.
Experts fear that if the scheme was widely adopted, Web transmissions would flood the airwaves, disrupting emergency communications and amateur radio signals, and interfering with the BBC World Service.
There is even a suggestion that they might upset the operation of Britain's electronic communications base, GCHQ.
The Digital PowerLine system from Norweb, a joint venture between United Utilities and the Canadian telecommunications company Nortel, transfers data between electricity substations and people's homes via the mains.
A conventional optical fibre cable connects the substations to the Internet.
The system can download data 20 times faster than normal domestic modems while leaving telephone lines free and is expected to bring about a revolution in Net access.
Engineers' oversight?
But according to the New Scientist magazine, engineers conducting the Manchester trial forgot to take account of the physical characteristics of streetlamps.
The chief engineer with radio systems consultancy Great Circle Design, Nick Long, told the magazine: "If you set out to design radio aerials to fit with this system, they would look like streetlamps.
"They are just the right vertical length of conductor."
Data downloaded by users of the system was broadcast by the streetlamps as radio waves with a frequency of between two and 10 megahertz.
Mr Long warned that if the technology was not modified some sections of the radio spectrum would become unusable.
In theory, the activities of people on the Internet could also be tracked by anyone monitoring the transmissions.
British users of the affected frequencies include the BBC, Civil Aviation Authority and GCHQ.
A GCHQ spokeswoman told New Scientist: "We are trying to gauge the level of risk."
Meetings planned
The Department of Trade and Industry's Radiocommunications Agency is said to be holding meetings with Norweb in the hope of finding a solution.
John Seddon, operations director for the company, was confident that the problem would not be a major hurdle.
"The technology that will be deployed in volume will be at low power levels in comparison to the general radio noise that's already out there," he said.
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US has companies that will do PL comm also
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by N4TSV on April 10, 2001
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try web sites of intellon corp and home plug and play alliance for what the USA has planned for comms over the powerline at a 10MB-15MB data rates. Then imagine what it will be like in a million homes. These are responsible companies that are doing there home work and some even have hams (engineers) on the payroll. But remember they are also share holders...I'm sure these systems will pass the FCC limits. But are the FCC limits adequate?
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PLC in North America
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by DJ7MGQ on April 12, 2001
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Taken from:
http://www.eetimes.com/printableArticle?doc_id=OEG20010406S0058
> Norman said he thinks the Intellon offering will
> struggle to compete globally because it will
> not meet the stricter CISPR-22 electromagnetic-
> compatibility regulations adhered to outside
> the United States and Canada. "The FCC emission
> regulations are 100 times less rigorous than
> CISPR-22," he said. "And we are demonstrating
> systems now."
vy 73 de toby
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