Could Broadband Over Power Lines be Dangerous?

falconfighter writes " Broadband over Powerlines, once touted as the solution to many internet problems (developing 3rd world countries, etc.) has a new hazard. The system basically involves putting high amounts of modulated RF on a power line. The Amateur Radio Relay League has the most informative page on the topic. The hazards include exceeding MPE (maximum permissable exposure), RF burns, and disrupting the HF bands of radio. This last one would also work in reverse, meaning hams, airplanes, or the military keying up their radios could take out large areas of internet service (with airplanes, potentially over several hundred miles)."

This isn't news...

[Jay Maynard]

...well, mostly. The hazards of RF exposure are controversial at best, with widely varying opinions in the medical community and no real, controlled studies. It's pretty certain, though, that at the low HF frequencies that the BPL folks are proposing, the effects of exposures to a few watts are pretty minimal.

This doesn't mean that BPL is a good idea. As the ARRL (which stands for American Radio Relay League) correctly points out - and has been covered on Slashdot before - BPL is a disaster for HF radio communications. Government agencies are weighing in strongly against it. I doubt it'll see the light of day in widespread use in the US.

Down already?

[CaptainAlbert]

Seems to be Slashdotted already, even though I'm seeing 0 comments @ -1...

Then again, I didn't think anyone really believed this, did they? I mean, any first-year EE student can tell you that mains cable is no good for signalling on, even at modest frequencies. Bah.

Re:FUD

[Zondar]

Yeah, it works. The question is, at what cost?

Do you really know what the amateur radio community does for the public, rtp?

Here in Spain

[octal666]

That is in South Europe, just in case anyone doesn't know, we have broad-band over many companies, but main power-line distributor, Iberdrola, is now starting to offer this service with lower prices than other operators. I was thinking to switch to them since they offer lower prices and better service, and they have even run a test program over a few months in the city of Zaragoza and near country area with no known problems, I'm surprised to see that news here.

Re: Lets hope someone takes a wise decision

[Zondar]

From the article, it appears the Japanese already have decided to kill this system.

http://www.jarl.or.jp/English/4_Library/A-4-1_Ne ws /jn0208.htm

Maybe our lawmakers could have their aides read up on why?

Suggested before

[PhatKat]

The idea of transferring data over power lines has been suggested before... but at least in the case reported in wired of Nov. 2001, it didn't work--despite what everone wanted to believe.

the article [wired.com].

Re:3rd world?!?

[AmigaAvenger]

That wouldn't solve the problem, HF interference doesn't exactly stop when it hits the border of a country, it is a worldwide problem.

The Instrument landing system

[AzrealAO]

would have had to be switched on by the pilots.

This story doesn't pass the smell test, or would you have us believe that planes run the risk of their instrument landing systems just "switching on" and attempting to land the plane automatically every time they pass an airport with ILS aids?

Re:Ham radio FUD

[falconfighter]

The reason is that we take care of the community in case of emergencies. In most cases, if something happens, hams are on the scene within 5 mins. We can relay messages in virtually no time (provided there's no other way to communicate) and basically are just there in emergencies.

Re:3rd world?!?

[TruelyGeeked]

This is exactly why the dangers of this potential connectivity option are much less hazardous than some would lead you to believe. They aren't talking about running data over every power-line in every building in Atlanta. The main areas I see this being used consist of rural areas and developing countries (when running power lines, why not run inet lines too?). These areas aren't going to have much stuff that causes/recieves interference.

FAQ

[Goody]

There's isn't a biological threat from BPL, but the interference issues are very real.

Here's a BPL and Amateur Radio FAQ [qrpis.org].

RF Hazard?

[fatboy]

The hazards include exceeding MPE (maximum permissable exposure), RF burns, and disrupting the HF bands of radio.

Um, you just made that up didn't you? I have never seen anyone, including W1RFI (Ed Hare), state that there was any type of RF hazard from BPL. It does pose a serious interference problem for anyone using HF, but not a health risk.

Power company has a network here in NY

[IGnatius T Foobar]

Here in the New York area, the power company (Con Edison) has a broadband network. You know how they did it?

They used the fact that they already own the poles, to string up their own fiber optic cable.

This, to me, is the primary indication that broadband over power lines just isn't going to happen. When even the power company doesn't believe in it, you know it's a dud.

Re:Aircraft ILS and power-line transmissions

[vlm]

Frequencies are wrong for ILS which runs adjacent to the VHF comm band, more or less.

Far more likely, was an IFR NDB approach where they were trying to use the NDB to avoid the mountain, unfortunately they managed to avoid the interfering power lines instead, thus hitting the mountain..

NBD freqs are in the 200 to 500 khz range which is adjacent to some of the signalling done in the sub 200 Khz range.

Are there 2 types of broadband-over-powerline?

[carndearg]

As I understood it from the last time this was mooted here in the UK we were going to see this as a last mile solution from your local distribution transformer to your home. The substation would get its internet connection via fibre and redistribute it in much the same way as low power mains intercom and network products work, with very low range. In the UK context this would be at the 11kv-to-240v transformer which usually serves a street of houses.

Am I right in gathering that the systems described here use high power HF on powerlines to distribute over much longer distances than this?

Power grid already has fiber...

[Goose Bump]

Here in the mid-atlantic region, AEP has most of their power grid strung with fiber alongside the power lines. I have a friend who works in a local office and he used to amaze me with the bandwith of their network. AEP uses the fiber for their company data and voice networks as well as leasing the lines out.

Re:Neighborhood popularity of amateur radio

[PatMouser]

Take a look at the Force-12 Sigma-5 for a nice vertical for limited space. I've got it, 145' of wire running to an AH-4, and a 3 element 6m beam (what, you mean it isn't a TV antenna?) up with no neighbor complaints.

K0OOK

Gimme a break

[siskbc]

What about those spider-web of antennae known as house wiring?

You do anything to your home grid serious enough to pose an RF risk to humans, and you'll blow the hell out of your breaker box.

Come on. Next cell phones really do cause cancer, I bet.

Re:LANs

[Anonymous Coward]

Same basic ideas, spread spectrum RF modulation being stuck onto the power lines. The outlet methods you mention use much lower power than would be required here. They also are limited by comparison in bandwidth they could offer.

Re:Here in Spain

[zoney_ie]

They may not be using power lines, it might just be extra fiber-optics alongside the power lines...

Certainly that's the case here in Ireland - ESB (Electricity Supply Board) hope to offer broadband soon by piggy-backing fiber on the transmission network.

The ESB has also done small-scale tests of broadband over the powerlines themselves. The radio amateurs were up in arms. I think I heard that the ESB may have been committing an illegal act in causing interference.

I don't know what the results of the tests were or how much radio interference was observed. Perhaps someone else knows.

Re:Yes, BPL is harmful

[Zondar]

Loved this section from the FEMA document...

"As pointed out in numerous stories and reports from countries where BPL implementations have been tested, the unavoidable radiation from power lines and associated modems raises noise floor limits to an unacceptable level. This interference will severely impair FEMA's mission-essential HF radio operations in areas serviced by BPL technology. Tests have shown that in order for licensed transmitters to compensate
for this noise level, there would have to be an increase in the signal level on the order of
+30dB

6. FNARS utilizes transmitters that range from 1 kW to 10 kW in output power. An
increase in power of +30 dB to offset the increased noise floor would require a 10 kW
station to increase power output to 1 MW."

And the 30db figure came from tests in Finland, where they also shot down BPL.

FEMA's quotes: See Gerhard Latzin, "PLC for the present rejected by Finnish Telecommunication Minister", 25 May
2001, published on the Internet at http://www.darc.de/referate/emv/plc/plc-oh.pdf; Ministry of Public
Management, Home Affairs, Posts and Telecommunications, Japan, "Announcement of report by Power
Line Communication Study Group" 9 August 2002, published on the Internet at
http://www.soumu.go.jp/joho_tsusin/eng/Release s/Te lecommunications/news020809_3.html; Koos
Fockens, "PLC Measurements", 7 May 2002, published on the Internet at
http://www.darc.de/referate/emv/plc/VERON_PLC_ Repo rt.pdf; Mel Maundrell, "Concerns for the continued Military Use of HF over the Potential Increases to the Background Noise Level", 11 January 2002, published on the Internet at http://www.radio.gov.uk/topics/interference/docume nts/dera.pdf

And one other gem section:

"Currently, there is no alternative to HF radio
communications in terms of meeting national security and emergency preparedness
requirements at the national, state and local levels.
10. FNARS HF radio stations are normally located in residential areas that would be
serviced by Power Line Communication (PLC) systems. FEMA also utilizes HF radio
stations from other Government programs, including the Military Affiliate Radio System
(MARS), the US Air Force Auxiliary - Civil Air Patrol (CAP), and the Radio Amateur
Civil Emergency Service (RACES), which are similarly situated. The interference from
PLC would render these essential communications services useless.
2002, published on the Internet at http://www.radio.gov.uk/topics/interference/docume nts/dera.pdf

Once upon a time...

[Maresi]

there was an emergency training in Linz/Austria.
The training was designed to simulate an major accident (if I remember it correct, it was an explosion of a chemical plant) and to practice the coordination of firefighters, the Red Cross, the police and several other organisations.
Linz, wich has some 18,000 households, is "Austrias powerline city", wich means, it has about 900 working powerline installations.
But these 900 installed plc units were enough to completly suppress the radio units used by some of the participants (e.g. the Red Cross).
These teams had to abandon the training, since communication was near impossible!
Imagine an real accident: No Red Cross or other ambulance teams! (In Austria, the Red Cross still has the major peace of the ambulance-business-pie).

Id rather get hurt on the countryside!

Re: NGO's

[bobv-pillars-net]

NGO's are INCREDIBLY annoying...

NGO = Non-Governmental Organization. [reference.com]

The logical conclusion from your post is that all Organizations should be Governmental.

My church is a Non-Governmental Organization.

So is the company who happens to pay my bills.

Obviously, you must live in a country where private ownership of property has been abolished, and you like it there.

Re:3rd world?!?

[DukeyToo]

Actually, copper cable theft is a huge problem in some developing countries (South Africa for instance). It is stolen and melted down again for resale. The 2nd-hand market for mass quantities of fiber is not quite as simple.

BPLis not an RF-safety proble,

[w1rfi]

The FCC has limits to human exposure to RF energy, but broadband over power line that operates at the FCC limits of 30 uV/m at 30 meters distance cannot, under any circumstances, exceed those RF safety standards. On 30-300 MHz, the part of the spectrum with the most stringent exposure limits, the exposure level is at about 27.5 volts/meter -- a level about 120 dB higher than the levels permitted by Part 15 to unlicensed emitters such as BPL. Expressed in power, the BPL systems are permitted to operate at a level that is 1/1,000,000,000,000 of the FCC's exposure standards. The risk to broadband over power lines is that the levels are strong enough to cause harmful interfernce. As a secondary issue, at least one system has been demonstrated to be susceptible to interference from amateur radio and presumably other HF operation. The RF levels of BPL systems are, however, nowhere near the levels that could exceed the RF-exposure limits. Ed Hare, [e-mail]

Re:Are there 2 types of broadband-over-powerline?

[bonnyman]

There are three powerline communications applications in use:

1. Broadband over power line systems described here are all last-mile access systems for use on medium voltage (approx 1 kV to 35 kV) and low voltage (under 1 kV). These are for linking internet users to an ISP (either the power utility or someone partnering with the utility). These are broadband speed systems.

2. In home power line broadband for linking computers and other devices within the home over short distance. These are all low voltage, broadband speed systems. The HomePlug [homeplug.org] specification was developed by manufacturers in cooperation with the ARRL and other HF spectrum users.

3. Traditional narrowband power line communications systems used for power systems for several decades for remote meter reading and relaying. These operate on many different voltages but at low speeds. (You can read 1000s of meters per hour using 4800 baud speeds.) These systems are not at issue.

Re: Lets hope someone takes a wise decision

[ZPO]

Its also the key backup comms network medium in the US for a little tiny organization known as FEMA (Federal Emergency Management Agency) - yes I'm being facetious about the "little tiny" part.

FEMA submitted comments to the FCC Notice of Inquiry that pretty much say "if you do this you will disrupt official government communications affecting the health and safety of US citizens". The NTIA didn't like it much either.

I'd say there will be some trials conducted with FEMA and NTIA watching very closely. The first time it increases the noise floor in their receivers 1-2dB BPL will be a dead issue in the US.

Trouble in Spain

[wsanders]

No matter where in the world you go, BPL/PLC is trouble: The URE (Spain's ARRL equivalent) has documented interferece in Zaragoza - they have a rather pathectic web site with no functional content - one can find it by googling - but I quote the PDF document at http://www.darc.de/referate/ausland/iaru/eurocom/e uronews1103.pdf,

"About PLC, a strong movement against it has been started in Spain, led by the Union de
Radioaficionados de Espana (URE).
Accurate measurements done in Zaragoza have demonstrated the high level of interference
(around -61 dBm), masking practically most ham signals in the 30, 20 and 15 meter bands.
Consequently, the URE delegate in Zaragoza has prepared a complaint, accompanied by a
detailed technical report showing the interference levels measured at several places in the
city.

"This complaint -the first one in Spain- will be submitted tomorrow [ 29.10.2003 - wsanders ] to the Inspeccion de Telecomunicaciones of Zaragoza."

I'm a Ham for whom even non-PLC interference from arcing power lines is a continuing problem. I don't think the power companies, at least in my area, are sufficiently staffed to roll this out - or do you want your average-Joe cable installer messing with 19 kV transmission lines? Fortunately the technology seems to have a short lifetime; it will soon be surpassed by effective fixed wireless services; the final nail in PLC's coffin may be recent objections from the Department of Homeland Security.

Re:First, and...

[Woody77]

spread-specturm over power lines has been proven to be a bad idea.

It works, IFF the impedance across the frequency range that you're using stays the same, or you have the ability to react to the real-time changes in impedance at different frequencies due to motor start-ups, shut-downs, and who's got what on.

The cable wiring is terminated, and is a bus that's designed to carry data. It's the obivous choice.

Broadband over powerlines is only usefull for getting lots of attention from investors (who just seem to love it), but they have no clue just how hard it is to get any kind of reliable throughput through it.

I've personally seen amazing stuff in labs, and watched it work great in a friend's brand-new apartment, but as soon as it hit the the 30 year-old wiring in my apartment, it wasn't so happy. Add in ONE bad light fixture (halogen that was arching lightly between the bulb and the contact), and no communication at all. The RF noise from the arching killed it.

Then you have another problem with power-line distribution. And that's transformers. RF doesn't like going through transformers designed to step 60/50Hz AC power up/down from the high voltages.

Re:The Instrument landing system

[henryhbk]

Unfortunately the smell test you speak of would pass the test. The ILS doesn't "Land" the plane, anymore than GPS would, it is simply a navigational aid which tells a pilot under instrument conditions (i.e. can't see well) where the runway is. If you remember this occurs in the Bruce Willis movie "Die Hard 2: Die Harder" where the terrorist reset the "ground level" on the ILS, and the pilots who were landing in the fog/snow and couldn't see the ground, fly the plane into the ground (manually but they "see" the ground being lower than it really is). For a description click here (http://www.allstar.fiu.edu/aero/ILS.htm)

This could certainly happen, although whether it could be interfered with by this BPL system is unknown.

Re:Just raining money over there...

[Anonymous Coward]

It's not that easy. Special equipment has to be added to route the BPL signals past distribution transformers, phase compensating capacitors, etc. that must exist for the power system to do its job. There's also the matter of the many branches off each power line (signal reflections) and the need for bidirectional repeater amplifiers along each line (generally at least one per mile). Then you must protect all this sensitive gear from lightning strikes, meaning direct strikes to the system (much of the third world population is in tropical areas with frequent and very powerful electrical storms). Add this to a low population density with a low income, and the number of subscribers per mile will not be enough to turn a profit. They have enough trouble just trying to keep the power on. Unlike what we're used to in North America and Europe, they often have power for only a few hours each day (it's too expensive to run the generators 24/7). The thought of broadband in these places is a joke--they're still waiting for reliable power, a phone line, and clean water. Clear your brain of Western notions, and consider what's really important to a poor country.