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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)."
...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.
Disinfect the GNU General Public Virus!
Yeah, it works. The question is, at what cost?
Do you really know what the amateur radio community does for the public, rtp?
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.
DON'T PANIC
From the article, it appears the Japanese already have decided to kill this system.
e ws /jn0208.htm
http://www.jarl.or.jp/English/4_Library/A-4-1_N
Maybe our lawmakers could have their aides read up on why?
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.
"Give a man a fire, he's warm for a day, set a man on fire, he's warm for life."
There's isn't a biological threat from BPL, but the interference issues are very real.
Here's a BPL and Amateur Radio FAQ.
Tired of being "punished" by the Slashdot $rtbl since 2002. I'm now over at http://soylentnews.org/ .
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.
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Loved this section from the FEMA document...
e s/Te lecommunications/news020809_3.html; Koos_ 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
e nts/dera.pdf
"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/Releas
Fockens, "PLC Measurements", 7 May 2002, published on the Internet at
http://www.darc.de/referate/emv/plc/VERON_PLC
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/docum
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, W1RFI@arrl.org