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Hams Complain about Powerline Broadband
dwm writes "Think
broadband over power lines (BPL) would be wonderful? There might be some collateral damage. The American Radio Relay League (your friendly neighborhood ham radio operators) have documented dramatic HF radio interference in areas where BPL is being tested (Check out the video of actual interference)."
That is one of the best ways to slashdot a site!! haha Very good technique grasshopper, but you are no match for my slashdot skill!!!
Slashdot.. Land of nerds, trolls, and FlameBait..
How many people still rely on ham radio? Why havent they moved over to something a little more modern? Does ham radio have any advantages over current technology?
I'm sure the hams wouldn't mind so much if they realized how much free porn they could get with powerline broadband.
Do you even lift?
These aren't the 'roids you're looking for.
...Something tells me this site is gunna go down, so here's the text of the article:
NEWINGTON, CT, Aug 6, 2003--ARRL President Jim Haynie, W5JBP, says Broadband over Power Line (BPL)--if widely deployed--would represent "spectrum pollution" on a level that is "difficult to imagine." Haynie reacted after seeing videotape and early data from recent ARRL field studies in four states where BPL is undergoing testing.
"BPL is the most crucial issue facing Amateur Radio and the one that has the most devastating potential," Haynie said. In terms of interference potential on HF and low-VHF frequencies, "nothing is on the same scale as BPL."
A form of power line carrier (PLC) technology, BPL would use existing low and medium-voltage power lines to deliver broadband services to homes and businesses. Because it uses frequencies between 2 and 80 MHz, BPL could affect HF and low-VHF amateur allocations wherever it's deployed. BPL proponents--primarily electric power utilities--already are testing BPL systems in several markets, and one reportedly is already offering the service. FCC rules already allow BPL, although industry proponents want the FCC to relax radiation limits. It's feared such a change could exacerbate BPL's interference potential.
At the West Gulf Division Convention (Austin Summerfest 2003) August 1-2 in Austin, Texas, Haynie previewed a short video (see below) that covers highlights of a recent field tour by ARRL Lab Manager Ed Hare, W1RFI. The video, which will complement technical data ARRL is gathering and compiling, turned out to be a real eye-opener for many in the audience.
Walt Dubose, K5YFW--assistant chairman of the ARRL High Speed Multimedia (HSMM) Working Group--said it was about what he'd expected. "But for most attending--maybe 60 percent--it was much worse than they had imagined, and for some it was a real shocker," he reported. Dubose said a few of those viewing the video simply couldn't believe that BPL actually was causing the high noise level.
In late July, Hare traveled some 1350 miles to visit BPL trial communities in Maryland, Virginia, Pennsylvania and New York to take measurements over significant parts of the HF spectrum. He also took initial readings at low-VHF frequencies. Driving a specially equipped vehicle loaded with radio gear and measurement devices, Hare said he didn't need to look long or track down "a few hot spots" to find BPL interference. "The signals were all over," he said.
"The interference found ranged from moderate to extremely strong," Hare said. The video shows the S meter of an HF transceiver holding steady in excess of S9 as the speaker emits a crackling din, which one observer described as sounding like a Geiger counter. Only the very strongest amateur signals broke through on 20 and 15 meters. Hare noted that the field strengths of the various systems all were within FCC Part 15 limits for power line carrier (PLC) devices.
At a couple of points, the video shows noise continuing nearly unabated on 15 and 20 meters as the car moves down long streets lined with overhead wiring. Hare said the signal propagated for at least a couple of miles down one road.
"Signals would have been much stronger using a gain antenna," he observed. Hare's vehicle carried a roof-mounted, horizontally polarized Buddi-Pole antenna--a loaded dipole.
Each BPL system exhibited a unique sound depending upon the modulation scheme it used, and Hare said he was able to distinguish three types during his recent tour. While in most cases, the signal sounded like static or pulse noise, in one city, it resembled sort of interference a computer monitor or similar device might generate, with warbling "birdies" blanketing the bands at closely spaced intervals. "Naturally, overhead wiring was the worst," Hare said. BPL signals continued to be audible in neighborhoods with underground electrical utility wiring, although it was somewhat attenuated.
The ARRL already has filed a 120-page package of text and technical exhibits
I can see that video getting hammered.
I'm grabbing a copy here
Get your own free personal location tracker
I'm a HAM radio oprator. It bothers me that some pople don't see anyting wrong with creating interference on already allocated radio waves. What if the same companies started to interfere with WiFi bands ? How would you react ?
I punched a baby once.
The movie site is pretty slow, so I mirrored it: BPL_Trial-small.mpg
by the amateur radio community is that this internet signal is transmitted through the electrical lines at frequencies from 2Mhz to 80Mhz - 80 through 6 meters. Studies have shown that, at the power levels suggested by the power companies along with the transmission lines acting like very large antennas, the typical amateur operator with have an estimated 33.7db to 65.4db of additional ambient noise to contend with, and would obviously ruin ham radio.
Would it be a huge problem for Slashdot to download the video first and then put up a bittorrent link for the file? Really -- any video link posted in a story immediately goes down due to mega-traffic.
Thoughts?
Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
They're not "hooked up" [think terminated], so there's lots of spare wire serving as an antenna and corrosion serving as a discriminator -- no wonder you're getting "interference" -- you have a simple radio reciever. Put a small cap across the speaker terminals and your problem goes bye-bye.
"You might as well get your son a ticket to hell as give him a five string banjo." -unknown minister
Well yes. If this BPL stuff is causing harmful interference, I will not 100% be for the use of it - Partly because I am a ham op myself.
That said, BPL does seem like a promising technology. This way, the electrical utlity can also sell internet, allowing the consumer to benefit from market competition.
For me, I see HAM radio's biggest benefit to society being when disasters strike and nothing works (phone, cell phone, etc) HAM ops are able to get communication going and assist emergency response efforts.
Now, if this BPL is causing HF interference, thats OK! after all, in the event of an emergency and the power is out, NO HF noise caused by BPL!
-Grump.
Is it true that more people vote for the winner of American Idol, than vote for the president? -Ali G.
Troll!!!
I'm sure I'm not the only one that finds bouncing radio waves off the atmosphere a ton more interesting and impressive than sending some packets over the internet.
I'm only into shortwave, I'm not a ham, but I can pick them up.
Picking up someone in Ecuador for example is a LOT cooler than getting an email from someone in Ecuador.
The RFID tags are being increased in power as well, which will interfere with amateur radio too possibly. Not sure on the techie details as I'm relatively new to this.
I don't recall seeing this in any DARPA specifications. It was designed to provide network communications over unreliable links. And before people go off bashing ham radio, consider that Karn's Algorithm, a critical component of TCP/IP without which the Internet would have died long before the present number of hosts, was developed by Phil Karn, KA9Q (a ham radio operator) to solve problems with TCP over AX.25, the ham packet radio protocol.
"The Internet" would not survive a nuclear strike. Hell, as we have seen great swaths of it can be taken out by a clumsy backhoe operator. Ham radio definitely has uses. In fact, ham radio could quickly be brought to bear to provide TCP/IP links to replace damaged infrastructure.
Ham radio is often used to provide communications following disasters like hurricanes.
No doubt the Internet is more important, and more capable than ham radio in general, but with my ham gear and a 12v battery I can provide significant communications for a lot of people. How much of the internet functions when a whole city's power grid is out?
Oh goodie, they're going to splatter all over the low TV channels and the first harmonics will trash the VHF band as well, not to mention low-band VHF used by many police/fire departments in rural/hilly areas.
"You might as well get your son a ticket to hell as give him a five string banjo." -unknown minister
Of course, it is largely isolated from the main Internet, since there are a lot of restrictions as to what can be done with Amateur Radio (no commercial use, no swearing, etc.) as opposed to the Internet at large.
I'm a ham, and I don't think this is a troll. It brings up a very valid point about the relative merits of two different communications paradigms.
HF ("short wave") communications certainly lacks the strategic and commercial importance it once had. It's always been a relatively-noisy, unreliable, and bandwidth-constrained way to communicate, and nowadays, HF is used primarily as a backup for satellite and long-haul microwave circuits. We could live without if we had to.
If, by sacrificing the entire HF radio spectrum, we could actually wire every home in the USA for economical broadband Internet access, I honestly wouldn't oppose it. Amateur Radio operators and commercial/military/governmental HF operators alike should realize the truth: we can't shy away from the technological, economic, and social potential of universal broadband Internet connectivity because of the lamentations of a few modern-day buggy-whip manufacturers.
Now, as a disclaimer, I will say that I don't believe that power-line distribution makes sense for broadband Internet. The power companies have spent the last hundred years optimizing their network to ship 60-Hz sine waves around, and trying to shovel data through a network like that is bound to be more trouble than, say, running fiber to every curb in America.
Dahlmann tightly grips the knife, which he may have no idea how to use, and steps out into the plain.
Yes, broadband over powerlines has proven to be a technological dead end. It's been tested over here for several years, and it's just not worth it compared to already installed adsl or cable.
The power companies is doing one thing right though, with every new long span high voltage line they're laying, they're twirling fiber with the lines. That's the future. A fiber channel into each and every home.
How small a thought it takes to fill a whole life
I'm N7ZTT. I can never get my extra class license now that they lowered the morse code test to 5wpm - the advanced class (which no longer exists) is my only proof that I can transmit data by hand at ~10 baud (yes, faster than some early modems! 13wpm = ~10 baud)
:-)
If you follow that link, you'll see I earned my advanced class in 1993; I received my first license in ~1991. But I'm not an old fark, I was homeschooled & did this for part of my curriculum. I'm only 23
I'll make another post in a few minutes that won't be a brag thread. It's actually sorta sad to see Ham radio fading out. You can do everything and more on the internet than you can on amateur radio. Of course, if we had wide-scale power outages & the sun was spewing crud at our atmosphere, morse code could potentially be the only way to quickly send information to other countries. Due to the nature of morse code, it can be deciphered even with a very low S/N ratio.
Anyway, I'll make a more intelligent post soon:
The same place they found them after 9/11 where ham radio was the only reliable mode of comms around ground zero for a couple of days. You know who told the disaster workers WHO to contact to start getting phones setup? The Hams on site, who had contacts with the right folks
You live in, let's sa the LA area (you mention earthquakes). No a search on LA and CERT. The hams TRAIN to work with the police and fire departments in case of disaster
Look up ARES - The Amateur Radio Emergency Service
Look up the fact that ARES works closely with the Red Cross, the Dept of Homeland Security, FEMA, LOTS of fire departments, wilderness rescue teams and the like
Look up RACES - Look up what happens if the Government declares a Radio Communications Emergency (and think about what happens to your 802.11 links - say "Bye-bye")
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
Have the proponents of BPL considered that it may be a violation of international treaties governing the use and allocation of the RF spectrum? If I want to put an HF transmitter on the air, I must obtain a license from my country's radio administration, who in turn is required to follow international treaties that say what frequencies and emission types are available for specific classes of users. There are bands reserved for broadcasting, ships, aircraft, amateur radio, etc.
Mea navis aericumbens anguillis abundat
Packet radio is extremely routable. TCP/IP is one way we do it, but actually is not the most common method.
As another poster pointed out, amateur radio operators mainly use AX.25. Both TCP/IP and AX.25 are X.25 derivatines. AX.25 identifiers are Amateur Radio callsigns with numeric suffixes (such as "N0CALL-10"). AX.25 routing is done by broadcasting while gradually incrementing your TTL until someone hears them for you (if they aren't your immediate neighbor), or manually entered information (either as a route table or "Connect to SOME1 via SOME2, SOME3, SOME4").
There are also a few other ways (such as NETROM and ROSE) amateur radio operators can route information digitally. While it would be a stretch, NETROM could be considered our equivalent of BGP router advertising and periodic route annoucements. ROSE is a polled system similar to Token Ring.
We also have our share of propritary speedup techniques (such as KA-NODE from Kantronics) and experiemental protocols as well.
If all the technology used to drive the internet is down, so would be I imagine the powerlines; so in these destroyed or desolate areas with no cell towers or working cabling, the ham radios would work well enough, no?
I feel the need to point out to you that many people benefit from Ham radio. I'll probably get modded down for this, but I may as well burn some karma.
Many people appreciate the services provided by the National Weather Service. How many lives are saved by issuing severe thunderstorm and tornado warnings? While I don't know the answer, I'd be willing to bet it's a somewhat large number.
Do you know that the National Weather Service relies on storm spotters to provide them with information about severe weather? That's right, there's some things doppler radar just can't tell you. And do you know how much of that information gets from spotters to the NWS? That's right, it gets there by Ham radio.
And also, consider that many places just don't have internet connectivity. You don't think about it because you live in a wealthy country and you live a good life. But what about South America? What about Africa? What about Asia? It's much less expensive to build a Ham radio than it is to buy the parts for a computer.
Some radio signals reach to every corner of the planet, something the internet and broadband just won't do. It's not the most modern method of communication, but it's still one of the most useful and important.
And I won't even mention that Ham radio is often the first communication link to an area that's been hit by a disaster. Hams often help provide communications in the case of an emergency.
Hopefully you don't still think that only an elite few need or benefit from Ham radio. That's simply not true. In fact, complaining that it's so unfair that you won't have broadband over your powerlines because of Ham radio is far more elitist than any of the pro-Ham comments I've read so far.
The bottom line is that BPL's harmful effects ARE NOT limited to ham frequencies. There's a bunch of other services, both commercial and government, using HF from 2-30MHz.
Just as a few examples: Aeronautical HF, NOAA RadioFAX over HF, NOAA storm warnings broadcast by SITOR over HF, Federal and Marine HF frequencies... The list goes on forever.
So, it really isn't just hams that are going to be suffering. It's EVERYONE that uses the HF spectrum, including the U.S. Government!
How long do you think said government is going to let BPL exist in its current form once critical military or Justice Department installations start noticing the very same interference that'll be driving us hams nuts?
Bruce Lane, KC7GR,
Blue Feather Technologies
Passing data over power lines is irresponsible from an engineering perspective. Power lines were designed to carry very very low frequencies, 60 hertz to be exact. BPL is wideband noise from 1 to 80 megahertz.
:-)
Anyone with the slightest electical engineering knowledge knows that a signal of such high frequencies will be radiated and antenuated nearly immediately. The power lines are just awful transmission media for these frequencies. What is needed for the power cables is shielding -- that's what's known as coaxial cable. ( Why don't they pass data on cable ?
This is analogous to the water company trying to deliver water with perforated pipes. The water just spills out everywhere and every couple hundred feet they would have to pump in more water so that you had sufficient water pressure at your house.
BPL was rejected in Japan and Europe, becuase it polluted the spectrum so bad it was pathetic.
For those dumping on ham radio as being obsolete or feel broadband is more important, consider that this will interfere with many other services including international ship distress frequencies, government (including military) allocations, shortwave broadcasts, and most likely aviation and public safety frequencies. Is your ability to get high speed pr0n more important than all this ?
Why is everyone else (like the FCC and utility companies) saying this is great ? The FCC is pro-big business and pro-utility. Equipment vendors are retreading the same technology that was rejected overseas and not informing their clients, the power companies, of the true interference potential. The power companies are dying to get into the broadband race as the telcos have their heads up their butts with DSL.
We need broadband, but this is not the solution. We need to remove the barriers for DSL and cable. Power companies could leapfrog the telcos and cable companies with fiber into the home or unlicensed wireless from their poles.
Quite simply, BPL is DOA.
Tired of being "punished" by the Slashdot $rtbl since 2002. I'm now over at http://soylentnews.org/ .
Broadband over power lines is running a high frequency signal over unshielded, untwisted wire, for miles. Hmm, who would have thought that could cause radio interference? Maybe the power companies (and the equipment manufacturers) should have thought about this for a bit longer.
It's one thing to run fiber to the curb, and use a low-power signal to the home - that might be workable. It's basically what the hybrid fiber coax cable systems do, but their wire is shielded too.
If the equipment is generating this much RF interference, I don't see how the equipment could be certified for deployment. If it is certified, I'd be interested to know what agency put their mark on it.
Can You Say Linux? I Knew That You Could.
Sample size: 1
I have been reading /. for years and this is the most disappointing reaction to a story posting that I have seen to date.
/.ers are attacking amateur radio rather than seeking more information about the service. "Hams" are not just ten old guys sitting around using "CBs" to talk in some antiquated manner or a bunch of old guys hunched over a telegraph key slowly tapping out morse code. Amateur radio is also not just an "emergency" service -- although some amateur radio operators do participate in emergency communications. You would be amazed at what amateur radio has to offer -- GPS location services, radio/Internet interconnects, satellite communications, digital communications, microwave projects, rural Internet, and other bleeding edge projects. Many of these projects will become standard /.er fair in five or ten years.
First, BPL is proven to cause interference to more than just amateur radio. Amateur radio operators are one of the few groups that has the skills and capabilities to prove the problem exists before a major mistake is made in deploying BPL.
Second, I have seen a number of anecdotes indicating that "ham" radio operators are jerks and, therefore, apparently should not have any rights. Obviously, in any group, a small minority of the members may be jerks. However, "hams" are by far one of the kindest, most intelligent, and thoughtful groups that I know. It is not fair for me to minimize the "jerk" problem, but I cannot see a link between being a jerk and having rights taken away. Get to know some real amateur radio operators and you will see a dedicated, service-oriented, and technologically cutting edge group.
Third, amateur radio operators are licensed by the FCC. The licensing requires extensive testing and is conducted very professionally (locate a local VEC session and you will see what I mean about professionalism). The tests are rigorous, especially for the higher classes, and require the applicant to be seriously interested in radio and technical communications.
Amateur radio operators are not a bunch of people with "CBs" sitting around making life difficult for others.
Forth, amateur radio operators are largely responsible for many of the "Internet crowd" technologies. Wireless Internet (I was doing that in 1990), satellite tv, "cell" phones, etc. were all largely based on amateur radio technologies. Amateur radio is really a cutting edge scientific and technical discipline.
Fifth, and probably most important, BPL may sound like an excellent idea; but the telecom industry promised broadband access via standard telephone and digital line technologies to most people in the US by 2006 as part of the mega merger process in the 1980s and 1990s. In exchange for creating mega-monopolies, the telcos promised to provide broadband services. The telcos, however, have heavily lobbied Congress and state governments to conveniently "forget" this little deal because it is now "too expensive." If the telcos would be held to their agreements, poor technologies like BPL would not be needed. Think about it: do you really want your Internet connections from a high voltage/amperage power line? Contact your Congressperson and state representatives and ask why the telcos have not lived up to the commitments.
I guess I am just disappointed that a number of
Sorry to get on my soap box.
Check this out..
There's a link there for the PDF of the spectrum allocation. Pretty much "DC to Daylight". The piece that BPL is going to destroy covers a lot of Ham allocations. But it also covers things like:
Maritime Mobile
Aeronautical Mobile
Space Research
Standard Time Signals
Shortwave Broadcast
Radio Astronomy
Land Mobile
Fixed-station
The amateur service is a very small part of the spectrum below 30 Mhz. A lot of it is used for things like trans-oceanic flights, military and civilian mobile services, and the like.
I'm of two minds whether this will pass or not. Michael Powell, the FCC chair, hasn't made a good decision since he got into office, so I'm thinking this will go through because he's got the power companies all giving him blow jobs under the table. On the other hand, the FAA, NTIA, the military, and the shortwave broadcasters may get through to the FCC that they can't allow this, and maybe somebody will get that lamebrain Powell to do something right.
I don't want to sound troll. But this thing (ethernet over power lines) has been freaking out ham radio operators all over the world for quite some time. Look for example here [eham.net]. And based on the law "if the shit can happen it certainly will" this will bring EMI problems to all equipment that is connected to or in the vicinty of the jack in the wall. Your TVs your stereos your computers etc.
Besides have anybody of had to deal with power companies? Do you really want THEM to provide your internet connection? Or even being involved in providing one.
Time and time again it returns (and will keep returning) to the simple truth. You need an adequate infrastructure to provide high speed Internet.
In the beginning of DSL I kept hearing a lot of strange things going against physics. Such as UTP (unshielded twisted pair) is better than coaxial cable etc. Well guess what, being entirely untrue this is not the end of the story. The pair that runs the phone line in your home/appartment is not even twisted, its flat (and it's CAT 3 most of the time to the central office).
It took huge amount of money to put power lines, phone lines and CATV into every home. And the companies that were doing that were cutting costs like crazy. Which means that nobody ever thought that someday it will be used for something else besides its initial purpose. And again based on the law I mentioned in the beginning it will be probably the worst case scenario for anytiing else. In case of DSLs that certainly is crosstalk and EMI and also distance. For example in my case no DSL provider does even want to install it for me citing that I am too far from central office.
Personally I think the interrim winners of all this will be the cable companies. Just because the people who decided to get broadband internet access usually go all the way once they've set to have it. Most people I know who started with DSL eventually just switch to cable modems. But eventually every body will lose because again CATV was not intended for anything else. (Just an example untill recently CATV equipment manufacturers were refusing to use multilayered PCBs because it was "too expensive"). So this is it. People just keep their heads in the body cavities of their choice and keep selling each other a snake oil.
On the other hand. It would be actually nice (especially with current situation in tech sector of economy) if we'd start laying fiber to the home and/or build sane infrastructure for wireless access.
Just my $0.02
- Back off man. I am a scientist
There is a lot more in the affected bandwidth than ham radio. The hams are just the most vocal group to oppose BPL.
There is worldwide shortwave broadcast, citizen's band, government and land-mobile radio, too, including police and fire dispatch (although a lot of that has moved up to VHF higher, there is still a lot on "low band"), cordless telephones and baby monitors, television channels 2-6, etc.
So it's not just hams that will lose out if this technology is deployed. Shortwave listeners, public safety communications, other land mobile (there are a lot of utilities using these frequencies) and pepole receiving television off antennas will all find their communcations disrupted.
Not to mention the technical problems of distributing RF over a very-low-frequency network.
This is a bad idea, poorly implemented. Like a nuclear powered airplane with an air-shielded reactor. An idea who's time will never come.
there are 3 kinds of people:
* those who can count
* those who can't
please think.
Sure, the disaster area has no power, but what about the people you need to recieve you?
What benefits? no AM? no emergency services?(other emergency services as well as ham), Noise on non properly shield equipment(like most home electronic equipment)?
Now, what benefits of broadband are there? you can get email with dial-up, you can get IM with dial-up. clearly broadband is not a criticle need.
Don't confuse numbers of users with usefullness. Perhaps we should get rid of the firestaions, since they only help a small handfull of people?
The Kruger Dunning explains most post on
I have a license, KC5LHH. And while hams aren't at the forefront, neither is the emergency broadcast service. Hams train themselves to provide a worldwide communications network under the *worst* possible conditions. And while BPL would do much to harm broadcasts, I do think that proper power supply filtering and construction can greatly reduce/eliminate the problem. Just don't count em out. In the event of a disaster as trivial as a hurricane/earthquake, they are quite useful. And one day when some conventional/nuclear war takes place or aliens invade, you might owe them your life.
Why can't all fpga/microcontroller manufacturers just release free optimizing compilers???
After making wait him while I unpacked everything I needed to make my radios work we conducted some test and he was finally convinced I was not the cause of the interference. Even telling him that the radio gear was not even capable of being used at the time was not enough for him to think that someone/something else was to blame.
People resent being blamed for something that was not their fault even when the blame continues after his has been shown there is no way it could have been them.
That's great that if the power is out, the interference would be gone, but why would the HAM operators all over the country still be operating, if 99.999% of the time, they were drowned out by interference, they'd all be gone.
I'll call you on that :) FCC abolished the sending test how long ago? Pre-1993, at any rate...as that's when my Advanced license dates from. You can still receive at 13WPM though (and the test was kinda weak in my opinion...the examiners were amazed at five minutes of solid copy. A one-minute requirement strikes me as barely workable).
Get your extra. And hang onto your CSCE. I still have all of mine around here somewhere.
As far as all these chumps complaining about hams and their "private playground"--yeesh. The REASON for the amateur service is that it's proven, in technological and social resources, to greatly enhance the commons. Same basic reason we have copyright protection--investing or limiting the public domain in the short term to enrich it in the long term. If you want to eliminate all ham bands, fine. Never use your cell phone again. Or TCP/IP (look up Phil Karn...some of us know him as KA9Q). Heck, wireless networking owes a lot to TAPR and other amateur experimenters. Avoid anything using the microwaves--hams developed the technology to make them accessible.
Oh, you mean you want unlicensed usage? Fine. Plenty of bands for that. The ELF area, for example. Or 49MHz. You know why 49MHz, 900MHz, all those other unlicensed bands are shitholes? Because they're unlicensed. There's no responsibility for maintaining equipment or proper operating procedure. Nothing keeping the corporations off there.
The airwaves are a public resource. Ham bands are a publicly-available way to use them. Just like accessing other public resources may require licensing (such as operating a motor vehicle on the public roads), ham bands require licenses. That doesn't make them some sort of "exclusive club."
- If it interferes with Ham Radio, it also (potentially) interferes with radios used by people you may thank one day, such as firefighters, abulance drivers, police, etc...
Most emergency services are moving to the UHF frequencies AFAIK. In fact, most if not all in the NYC area are already, and I'm sure most other large urban areas have already switched. They're also using FM, which eliminates most interference.
Will the FCC care? Probably not. As long as everyone can get EyeWitless News and Clearchannel they're not concerned. Sure, it interferes with shortwave, but since VOA stopped broadcasting to North America, there's nothing on SW for Americans to listen to anyway (the FCC's hypothetical opinion, not mine).
BPL should never be approved for three, sinple reasons; 1. Injecting high frequency RF onto the power lines at levels higher than the limits specified in 1989 WILL cause interference across the entire HF bands (actualy lower levels will do that). This is illegal according to FCC Part 15. Any device doing this can and will be shut down. 2. An entirely legal amateur transmitter, say a beacon transmitting 100 watts at 28.2MHz, in a common suburban backyard will render the local BPL system useless; and according to Part 15 the BPL system MUST accept this situation. 3. It is entirely unnecessary for the utilities to use the 2 to 80 MHz band for this purpose. The FCC has set aside 435MHz at 5GHZ for the Unlicensed National Information Infrastructure. This is more than 5 TIMES the bandwidth BPL could ever hope to use in HF. Systems using U-NII can be deployed TODAY (google Motorola Canopy); are already being used for broadband internet access in several communities and require no further action from the FCC. All the utilities have to do is hang U-NII nodes on the power poles at 2 to 10 mile intervals, depending on local geography. All that remains is to convince the powers that be of the obvious.
Then there is possible international issues as the ionosphere doesn't obey any kinds of national borders when propagating signals. What if a US BPL installation interferes with radio communication in an emergency in China?
Now on to your question. All kinds of overhead transmission wires can and will act as long-wire antennas and will spread these signals around. Underground cables could be less radiating, depending on what configuration they are. Thus, I would expect a 3-core cable which is three conductors twisted like a rope to contain the signals better than three individual one-core cables laid side by side. However, once these cables emerge and connect to the wiring in your house, all bets are off. I would expect the house wiring to be the biggest radiator in suburban areas where the grid is underground.
Note that "long" in this context means longer than the wavelength of the signals. For a wideband signal like BPL, the shortest wavelengths are on the order of 2 meters, (7 ft)so any piece of wire longer than about 1/4 of this can radiate some of this signal. The longer the wire, the better the radiator and the more signal is emitted and interferes. The low frequency end of the BPL spectrum has wavelengths on the order of 300 meters or 1000 feet, so even a little neighborhood-sized power spur line could radiate a lot.
Considering that the power distribution network is designed for 50 Hz or 60 Hz and most components were either designed to block high frequencies or never had any specs for these high frequencies, there could be a lot of rework needed.
Just look at a commonly seen energy meter for example; an electromechanical meter of the kind counting your consumed kilowatt-hours. This is basically a big series inductor, which does a good job of blocking these high frequency signals. So every house may need some kind of RF meter bypass or at least the old electromechanical meters may need to be replaced. Everywhere.
Stringing fibers along the power-line rights of way would be a much better way of distributing these data signals. It might even be less expensive than trying to pass high frequency signals through devices handling high voltages. Some kind of bridge for the "last mile" appears to be necessary anyways.
SIGBUS @ NO-07.308
Broadband PowerLine (BPL) is an access technology. It is somewhat experimental and is being used to connect a service provider, like a Telco CO that is several miles from your home or business, to your home to provide broadband access. This technology needs a good deal of power to send signals over the Medium Voltage (~16 kV - think "finger of God") lines over great distances. This is the technology that the HAMers are upset about. This is also the technology that the FCC is looking at.
HomePlug Powerline technology is a home networking technology used to distribute the signal from your home gateway or music server to other devices or PC's in your home. HomePlug uses OFDM, a technology that puts a comb of carriers across the spectrum. With a comb we can then turn off and notch out the HAM frequencies. HomePlug goes from 4-21 MHz and has deep notches to prevent interference with the HAM bands in that space. A large number of FCC and CE approved HomePlug devices are available in the market (look for the NETGEAR Wall Bridges at Circuit City or the Devolo devices in Europe).
Just wanted to speak up because there's been a lot of confusion here. Intellon or HomePlug can put a whitepaper on this on their to-do list.
thanks,
James Mentz
Senior Applications Engineer, Intellon Corporation