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Utility Cuts Short BPL Trial
fatboy writes "The ARRL is reporting that Alliant Energy has called an early end to its broadband over power line (BPL) pilot project in Cedar Rapids, Iowa. The "evaluation system" went live March 30, and plans were for it to remain active until August or September. Alliant shut it down June 25. Ongoing, unresolved HF interference from the system to retired engineer Jim Spencer, W0SR, and other amateurs prompted the ARRL to file a complaint to the FCC on Spencer's behalf demanding it be shut down."
"unresolved HF interference from the system to retired engineer Jim Spencer"
It must be bad if poor old Jim was interfered with.
cLive ;-)
-- Trinity in high heels carrying a whip: The donimatrix - there is no spoonerism
I happen to live in the Cedar Rapids/Marion area and I didn't even know this was there. Why doesn't anyone tell us anything?! It would be an alternative to Mediacom and Qwest.
I'm incredibly glad to hear this. BPL has the potential to kill ham radio (and actually lot's of other HF radio services) as it uses HT powerlines that were not intended to carry HF signals and act as really excellent antenna (in fact the US Navy uses them to transmit extremly low frequency/long wavelength signlas to its submerged subs! So we know they work as antenna!)
I'm also glad the FCC isn't actually as big a patsy of the BPL industry as it first appeared. Cheers to the FCC and let's hope this is the first nail in the coffin of a truly bad idea.
As an aside: I hope this discourages the power industry muppets in the UK from trying the same thing.
Bad analogies are like waxing a monkey with a rainbow.
- Put up power lines - = huge aerial system
- Inject wideband RF into huge aerial system
- Interference!
In fact the whole idea of RF over power lines, though attractive at first sight, is a triumph of will over physics. A system designed to take kilovolts at around 50-60Hz, with mechanical switches all over the network and a mixture of capacitors and inductors to adjust power factor, is not a benign environment for RF. But people keep trying to do it. There have been attempts at LANs over household wiring - but wireless networking has just about killed that with a combination of speed, convenience and safety.You can adapt a car to travel on water, but the result is expensive and technically poor. In the same way, I feel broadband over AC power is a cross-model step too far.
Panurge has posted for the last time. Thanks for the positive moderations.
This is exactly the same reason that a Broadband over power lines experiment was given up by one of the UKs power providers (The predecessor to Scottish power I think).
I wonder why someone thaught it would be different in the US, even with its more stringent laws about RF interference.
Do these people not do basic searches on prior work?
You got all of that from Art Bell you big faker! ;-)
It goes from God, to Jerry, to me.
The last paragraph is quite telling actually:
That BPL means 'Broadband over Power Line', by the way.
I have to stop wasting so much time reading Slashdot. It's interfering with my crystal meth addiction.
Nice. I'm sure comms companies all over the US will jump at the chance to get the ARRL's contribution and involvement in future.
Either way, it's great to see that the FCC is standing firm to protect sad lonely guys holed up in their bunkers listening to strangers over the airwaves from the interference of sad young(er) lonely guys holed up in their bunkers looking at strangers over the ether.
Somehow the defeat is poetic justice.
Seastead this.
I live in Cedar Rapids and participated in the program. I didn't RTFA so I'm not sure what it says about this, but the mailer I got a couple days ago didn't say anything about a complaint, it just basically said Alliant had met its goals for the program ahead of schedule, and after working out a few issues there is a possibility the system may be implemented on a larger scale.
On the 0th day, God created C
I've never understood why they were so gung-ho about this stupid idea in the first place when most power grids already have multi-core fiber optic cable hidden inside the neutral wire. (they use it to communicate between substations and most of the capacity is dark - I put hundreds of miles of this stuff in the air back in the mid-nineties so I know from whence I speak) The power company already has the most valuable easements. Couple that with their existing fiber grid and they could have fiber to the curb in every major market for a lot less than the phone or cable companies who very often have to mount on existing power poles and pay $1 or more per pole for easement rights.
That's how SPRINT became a major Playa in the long distance and later, the backbone market - they used their existing easements. (for those who live in a cave, SPRINT stands for Southern Pacific Railway INTernational - your phone call 'rides the rails'...or more precisely, runs over fiber optic plowed into the roadbed of their gigantic network of railroad tracks)
If BPL was possible, it'd be in SimCity.
Nope, it doesn't appear to have been fully rejected. Scottish Hydro Electric appear to offer the service. Website with details here:
Cheers,Scottish Hydro
Mike
If you are truely a licensed Amateur AND a slashdot reader, then you have no excuse whatsoever to actually go and RTFA.
If you had done even a modicum of research into this, you would know that what the ARRL and others are complaining about is BPL or PLC in europe that uses the HF spectrum for transmission. Over long unshielded agind powerlines, this == big fscking antenna. Hence the bleed, and RF issues ensue.
They have also stated (the ARRL and others) repeatedly that they have no problem with BPL itself. They have problems with the power companies that are trying to roll this out to make an extra buck or two. I mean, lets face it, many power companies have problems just keeping the power going, let alone BPL... and to have to handle interference complaints as well?
But in any case, the people who are against BPL, as I said, are against the version that uses the HF spectrum. Not just parts of the HF spectrum, but the ENTIRE HF spectrum from around 3 to 30+MHz. They support other means readily, such as the BPL system that was being developed in the desert that used gigahertz transmission frequencies instead of HF freqs... or the aforementioned fiber wound around the power lines, and some companies ALREADY have cable wound around the powerlines that they use themselves.
"Our funds have never taken part in toxic or death spiral convertible financings of any sort" -BayStar's managing partne
Part of the reason for the protest has been that the power utilities have been very poor in the manner they respond to RFI complaints caused by their equipment . With that being a fact, why should hams trust that the utilities will do any better with BPL.
BPL can work, however, as it is being proposed, it is not setup to properly protect the liscensed users of the bandwidth that these systems will be radiating in. The power companies are lobbying to put in the system that requires them to do the least amount of work. Not a single one has proposed a system that would mitigate their response.
The United Power Line Council recently showed it had no real arguments against the hams cases when it responded to FCC comments by saying they were the true experts and "not a misinformed set of armchair amateurs that still use vacuum tube transmitters." Wow, name calling in a document submitted to the FCC. The simple fact is that they have not been able to refute the technical arguments. They are now trying to buy influence and namecall in order to get their way.
See Alan Crosswell's site for more information on BPL interference in his area.
All it takes is one location to roll out BPL, and the HF band is affected world-wide.
I predict the following:
Before anyone says how heartless I am to those poor ham radio operators: I am one. I'm just a realist.
In any situation like this, someone invariably gets picked as a 'test case.' Jim just happened to be the one.
What he experienced in terms of RF 'noise pollution' would become all too common if BPL were to be widely deployed. The NTIA report and the ARRL's own technical committee have demonstrated this in gruesome detail.
Want some more real-life examples of the kind of crap BPL is capable of spreading? Go here.
There are plenty of existing ways to deliver broadband to homes without polluting the HF spectrum. BPL exists only to serve the pocketbooks of its equipment manufacturers, and the shareholders of power companies, at the expense of EVERYONE (not just amateur radio ops) who uses the HF spectrum. If it becomes widespread, commercial aviation, military, and the federal government's HF users will ALL be affected in short order, and it will probably get shut down anyway as a result.
Why waste any more time on it at all?
Bruce Lane, KC7GR,
Blue Feather Technologies
In theory, you can use almost any pair of wires to carry a broadband signal. That's because in theory, any pair of wires are perfectly conductive. Also, as soon as an extra electron tries to enter one end, another one drops out the other end, instantaneously, and if you try to pull an electron out of one end, another will be sucked in at the other end, equally instantaneously.
..... well, they don't have a word for it, they call an engineer to fix it. But what you need to remember is that the potential difference (voltage) across a capacitor can only change gradually, never suddenly; and the current through an inductor also can only change gradually, never suddenly.
It ain't like that in practice.
Imagine a drainpipe stuffed with tennis balls. When you try to push in an extra tennis ball, what happens is that all the other tennis balls give a little, and for one fleeting instant there really is an extra ball in the pipe. Then the balls expand back to normal size and one is shoved out the far end.
Now, any pair of wires will have a capacitance (since they are conductors separated by an insulator), an inductance (since they are wires; at low frequencies you need a full-on coil to get any effect, but at high frequencies any slight bend will do the job) and a resistance (since they aren't perfect conductors). It's what electrical engineers call a composite impedance, and what everybody else calls
For any given transmission line, if you stick a battery across the terminals at one end and a resistor across the terminals at the other end, look at each end with an oscilloscope and have some magical way of lining up the time axes, you won't see just a simple step change of voltage. When you apply the battery to the T.L., it looks like some composite impedance (which it is) and likely draws more current than the resistive load at the far end wants, since it's charging up the capacitance of the line -- or less than that, since it's charging through an inductance. One or the other phenomenon will win out every time.
Once the capacitance of the line has charged -- via the inductance and resistance of the line -- it then begins discharging into the resistor on the far end. Actually, it doesn't wait at all, but starts discharging as soon as it has begun charging. And what you may even see, is a pulse of current reflected back towards the battery, if too much current went in at first compared to what the resistor was expecting. You can even get multiple reflections if the first one isn't exactly right. What you essentially see on the scope traces is a damped sine wave at the frequency at which the resistance and capacitance of the line resonate -- and a delay between applying power from the source and seeing it at the load.
That's what you get with DC. With AC, the capacitance and inductance tend to distort the shape of the waveform, but not change the frequency -- though it's very likely that other frequencies will be added in. Also, anything under a few hundred kHz behaves mostly like DC -- albeit more-or-less-slowly-changing DC -- but broadband networks need carrier frequencies measured in MHz, and by the timed you get to that sort of frequency, the AC phenomena are well established.
Now if all you are concerned about is getting the maximum energy throughput, as are the electricity board for example, then you want to minimise resistance (which turns energy into heat -- capacitance and inductance just store it in electric and magnetic fields, respectively, then give it up again) even if that makes the line highly capacitive or inductive. All that will happen is that you'll get a huge reflection the first time you connect up, then a series of ever-decreasing ones, but most of the power from your source ends up in the load even if it takes awhile to make it down the line, and even if the shape of the waveform is significantly altered.
If you want a transmission line that does not
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