well first off i'm a sparky for a major utility in the UK and routinely project manage the installation of overheads and cables etc.. so I'm fairly up to date with the latest & greatest
The first thing to point out is that you only get interference issues from overhead lines. Buried power cables are all screend, and laid in a special formation called trefoil, which virtually eliminates any associated EM field.
From a commercial point, by combining utilites i.e. power/Broadband your cutting down on running costs as everything is easier to maintain. Transmission/distributions systems are also a lot more secure (in terms of not going off) than telephone circuits.
For the overhead issues, firstly it all depends on which country you live in, the US/Canada has different votlages and frequency to everywhere else and is also much bigger with a lot more overhead. Therefore the practicalities are different; the phase spacing between the wires are much wider and creates a a larger interference area. In Europe the interference created is less of an impact.
Basically, BPL will be commercially very attractive in city centres where there either isn't a lot of fibre optics installed and/or the majority of the power network is fed from underground cables. As underground cables won't cause any interference and the bulk of the infrastructure is allready installed.
There is also an interesting variation on offer in the UK, called blink broadband. This takes the main ADSL connection from you telephone wires and then plug into your domestic power and use your own home main ring - you then plug your laptop computer into any power socket in the house and don't need to worry about having a phone point nearby. Not actually sure if its any use, as my guess is broadband will go wireless over then next decade.
http://www.blinkbroadband.co.uk/
Re:OT: Question for Slashdotters
on
Lego Logic Gates
·
· Score: 1
The programm i have been using for a p/t distance learning course is called OrCAD and happily runs all the basic logic gates, along with some of the more common IC's available. The demonstration version is free but only lets you have up to 60 componenets, but that should be more than adequate for most mini projects. The program (like any) takes a little while to get used to though.
Just an idle thought, but does anyone (physicist type's) know what would happen if you can get a farday cage to start superconducting. My theory is a little rusty here, but as a supercondutor expels its internal magnetic field wouldn't you effectively get a box that no EM wave could penetrate (including light)?
i did a few articles about power engineering topics, such as Real, apparent and reactive power.
Its easy and suprisingly satisfying.
similar scenario in Antarctica
on
Lawyers In Space...
·
· Score: 4, Interesting
There is a slightly similar situation in Antarctica, where a treaty exists in which no claims of ownership are recognised. I think its quite a common belief in some military circles that it could well be a serious point of conflict if any quantity of natural resources are found there. Its probably a very good model of how things might work for ownership of the moon and mars.
From an antarctic website:
In 1961, the Antarctic Treaty took effect with signatures from the twelve countries who participated in the IGY. The treaty is a surprisingly short and simple document, but it is one of the most successful international agreements ever made. It deals with issues regarding the future of Antarctica and recognizes that:
The Antarctic Treaty guarantees four things:
"Antarctica will remain open for scientific research to nations who agree to the treaty.
No military bases can be built on the continent.
There will be no testing of nuclear weapons or dumping of nuclear waste in Antarctica.
No claims of ownership are recognized or denied, and no new claims of ownership can be made.
Since the treaty took effect several additional countries have signed on and members have added laws to protect Antarctic plants and animals. In 1991, the treaty was further strengthened by the Protocol on Environmental Protection which defines Antarctica as a "natural reserve devoted to peace and science." Today, scientists maintain year-round research stations throughout Antarctica but it remains an untamed wilderness.
I thought the bet was with Kip thorne, if Hawking was correct Kip Thorne had to buy him a years subscription to penthouse and if he was wrong had to give him a magazine subscription for Kip Thorne (it could have been encycolpedias), i've a suspicion there was someone else involved as well
but isn't the equation a bit spurious? the whole equation 'assumes' there are planets/civilizations emitting EM.
From my limited knowledge of this, its a complete impossibility to predict how many civilizations can exist becuase we don't know the probability of life occuring.
What i mean is, there is only our planet that has life so we could be a 1 in 1000, 1 in 10000 1 in 10^100 etc.. becuase we dont have this starting number we can't do any effecitve calcs.
Saying that i bet there's loads of the buggers out there
Actually all (metal) cars will act as a cage to that kind of electric discharge. (unless the tyres catch fire, melt and you're sitting on the wheel hubs). The other option is to use some sort of grounding tails on the car.
I'm not too sure exactly how taser's work in detail (i'm guessing its DC - like a megger tester) but, if you wore thick/heavy non conductive clothing you should be safe.
It looks suspiciously like the 'XADS' has a pre-drilled bit of a transformer bushing(the ceramic/conductor you connect a cable to) sticking out to act as the 'nozzle'.
They have also been fairly widely adopted by several car hire companies that specialise in 'city nipper' cars.
I think that the cars are also exempt from road tax as well.
Yes you are nearly correct, but it only really matters if you suddenly kill power on a wound coil (like a transformer, choke or motor) as these type od devices basically store energy and discharge it quickly, in the opposite direction when the power is removed.
Car ignition works by collaping a voltage through a special ignition coil, which produces the big voltage spike.
Normally on a power system the voltage is killed whenever it's convientient. With some a.c. systems you do try and kill it as the voltage cycles back through its minimum point, but its not usual.
With process plants if we got any level of escaped gas etc.. you initate a level 1 shutdown which kills power to everything.
Even the UPS sytem that fed an automated tranmitter, the idea being that the transmitted radio waves could induce current and possibly lead to a spark in any nearby metal.
Petrol isn't quite as flammable, but the same principle applies. If you had you phone near a suitable surface an incoming call may well have the same effect.
Personally i'm more concerned about the mobile phone masts they have installed in petrol station signs.
For my 2 cents, i always regard maths as a tool and while i almost never actually do any calculus, vector calcs or matrix manipulation etc..
It's very reassuring to be able to look at some one elses calcs and think 'that looks about right'. I occasionally prod and poke at someone elses work but rarely have the time or inclanation to duplicate it. But i *could* if necessary.
Admiteddly i'm an elec engineer but i'd guess it must be a similar situation for most CS day to day jobs.
When they install power lines the sometimes include an optical fibre cable inside the cores sheathing, so your have say 3 huge copper conducting cores and a skinny little optical cable as well, all wrapped up by a protective PVC sheath etc.. It doesn't cost a lot extra as its installed and manufactured at the same time as the power cable. Its this otical ring theyre tapping into with their wireless network.
One of the high street stores in the UK (Marks & Spencer) has just completed a pilot test at one of its stores. Worryingly the Department for Trade and Industry actually subsidised the scheme, even more worrying was of the 50 people who were intereview about RFID no one seemed to care or be aware of the technologies issues.
The scheme used intelligent tags that "hold just the number unique to each garment. When scanned against an M&S database, the tag would only give information related to the product's size, style or colour."
Check out the full story at
http://www.silicon.com/software/security/0,3902465 5,39118147,00.htm
Just off the top of my head Its probably quite difficult. All the RFID chip is doing is responding to an outside pulse and using the pulses energy to respond back. You would need a fairly, powerful EM (electromagentic) source to fry the thing which aren't too easy to get access to. It probably wouldn't be too clever if you wearing it as well. (unless of course you believe that mobiles phone transmitters aren't bad for you either)
Interestingly though i doubt many RFID tags would stand up to a hot wash, plenty of water with detergent and a big motor as an EM source nearby driving it might well fry it... Dunno the thought just occured to me - anyone got any ideas how physically tough the chips are?
The best way would probably be to have a big magnet at home or maybe move to a house under a supergrid power line:-)
I see it as a question of the ease of tracking, I think it is basically a necessity of civilized society that if a criminal agency needs to track you it should be able to. At the moment its a non-trivial task to go about tracing someone who doesn't want to be found, so it only gets done in serious instances.
With the advent of all these new tracking systems, centralised global databases it data gathering becomes much easier, faster and more accessible. Its *this* that makes poorly thought out systems so dangerous as it vastly improves the potential its got to be abused.
What worries me the most is the fact that when government agencies go out to to contract usually the cheapest or their best buddy; and have a laughable record at dealing with sensitive information that isn't about them.
Have you been watching swordfish??
Actually you are pretty much on the right track, i used to work for a major oil contractor and whenever negotiations got a little *tough* i.e. the locals wouldn't do what was wanted. All the negotiators used to call it a day go back to the hotel for a few days and hey presto new locals to negotiate with...
'Where Vultures feast' is a very accurate book
-its easy to be calm when your sitting on top of a mountain and having nothing better to do
I think they mean the pre-cursor to International Friend or Foe (IFF) technology used by planes in WWII. If i remember right, they started off with the same idea of using a passive inductive loop that would respond to a transmitter in the fighter.
This might just be word play, but i read it that the kid thought he was selling the whole buisness for $10k. Wouldn't that get him out of the fire to an extent?
Slashdot Mirror
well first off i'm a sparky for a major utility in the UK and routinely project manage the installation of overheads and cables etc.. so I'm fairly up to date with the latest & greatest
The first thing to point out is that you only get interference issues from overhead lines. Buried power cables are all screend, and laid in a special formation called trefoil, which virtually eliminates any associated EM field.
From a commercial point, by combining utilites i.e. power/Broadband your cutting down on running costs as everything is easier to maintain. Transmission/distributions systems are also a lot more secure (in terms of not going off) than telephone circuits.
For the overhead issues, firstly it all depends on which country you live in, the US/Canada has different votlages and frequency to everywhere else and is also much bigger with a lot more overhead. Therefore the practicalities are different; the phase spacing between the wires are much wider and creates a a larger interference area. In Europe the interference created is less of an impact.
Basically, BPL will be commercially very attractive in city centres where there either isn't a lot of fibre optics installed and/or the majority of the power network is fed from underground cables. As underground cables won't cause any interference and the bulk of the infrastructure is allready installed.
There is also an interesting variation on offer in the UK, called blink broadband. This takes the main ADSL connection from you telephone wires and then plug into your domestic power and use your own home main ring - you then plug your laptop computer into any power socket in the house and don't need to worry about having a phone point nearby. Not actually sure if its any use, as my guess is broadband will go wireless over then next decade. http://www.blinkbroadband.co.uk/
The programm i have been using for a p/t distance learning course is called OrCAD and happily runs all the basic logic gates, along with some of the more common IC's available. The demonstration version is free but only lets you have up to 60 componenets, but that should be more than adequate for most mini projects. The program (like any) takes a little while to get used to though.
cheers
steve
Just an idle thought, but does anyone (physicist type's) know what would happen if you can get a farday cage to start superconducting. My theory is a little rusty here, but as a supercondutor expels its internal magnetic field wouldn't you effectively get a box that no EM wave could penetrate (including light)?
You forgot the most important one - it should meet the orginal user specification!
i did a few articles about power engineering topics, such as Real, apparent and reactive power. Its easy and suprisingly satisfying.
There is a slightly similar situation in Antarctica, where a treaty exists in which no claims of ownership are recognised. I think its quite a common belief in some military circles that it could well be a serious point of conflict if any quantity of natural resources are found there. Its probably a very good model of how things might work for ownership of the moon and mars.
From an antarctic website:
In 1961, the Antarctic Treaty took effect with signatures from the twelve countries who participated in the IGY. The treaty is a surprisingly short and simple document, but it is one of the most successful international agreements ever made. It deals with issues regarding the future of Antarctica and recognizes that:
The Antarctic Treaty guarantees four things: "Antarctica will remain open for scientific research to nations who agree to the treaty. No military bases can be built on the continent. There will be no testing of nuclear weapons or dumping of nuclear waste in Antarctica. No claims of ownership are recognized or denied, and no new claims of ownership can be made. Since the treaty took effect several additional countries have signed on and members have added laws to protect Antarctic plants and animals. In 1991, the treaty was further strengthened by the Protocol on Environmental Protection which defines Antarctica as a "natural reserve devoted to peace and science." Today, scientists maintain year-round research stations throughout Antarctica but it remains an untamed wilderness.
I thought the bet was with Kip thorne, if Hawking was correct Kip Thorne had to buy him a years subscription to penthouse and if he was wrong had to give him a magazine subscription for Kip Thorne (it could have been encycolpedias), i've a suspicion there was someone else involved as well
but isn't the equation a bit spurious? the whole equation 'assumes' there are planets/civilizations emitting EM.
From my limited knowledge of this, its a complete impossibility to predict how many civilizations can exist becuase we don't know the probability of life occuring.
What i mean is, there is only our planet that has life so we could be a 1 in 1000, 1 in 10000 1 in 10^100 etc.. becuase we dont have this starting number we can't do any effecitve calcs.
Saying that i bet there's loads of the buggers out there
Actually all (metal) cars will act as a cage to that kind of electric discharge. (unless the tyres catch fire, melt and you're sitting on the wheel hubs). The other option is to use some sort of grounding tails on the car.
I'm not too sure exactly how taser's work in detail (i'm guessing its DC - like a megger tester) but, if you wore thick/heavy non conductive clothing you should be safe.
It looks suspiciously like the 'XADS' has a pre-drilled bit of a transformer bushing(the ceramic/conductor you connect a cable to) sticking out to act as the 'nozzle'.
They have also been fairly widely adopted by several car hire companies that specialise in 'city nipper' cars.
I think that the cars are also exempt from road tax as well.
Yes you are nearly correct, but it only really matters if you suddenly kill power on a wound coil (like a transformer, choke or motor) as these type od devices basically store energy and discharge it quickly, in the opposite direction when the power is removed.
Car ignition works by collaping a voltage through a special ignition coil, which produces the big voltage spike.
Normally on a power system the voltage is killed whenever it's convientient. With some a.c. systems you do try and kill it as the voltage cycles back through its minimum point, but its not usual.
With process plants if we got any level of escaped gas etc.. you initate a level 1 shutdown which kills power to everything.
Even the UPS sytem that fed an automated tranmitter, the idea being that the transmitted radio waves could induce current and possibly lead to a spark in any nearby metal.
Petrol isn't quite as flammable, but the same principle applies. If you had you phone near a suitable surface an incoming call may well have the same effect.
Personally i'm more concerned about the mobile phone masts they have installed in petrol station signs.
For my 2 cents, i always regard maths as a tool and while i almost never actually do any calculus, vector calcs or matrix manipulation etc..
It's very reassuring to be able to look at some one elses calcs and think 'that looks about right'. I occasionally prod and poke at someone elses work but rarely have the time or inclanation to duplicate it. But i *could* if necessary.
Admiteddly i'm an elec engineer but i'd guess it must be a similar situation for most CS day to day jobs.
When they install power lines the sometimes include an optical fibre cable inside the cores sheathing, so your have say 3 huge copper conducting cores and a skinny little optical cable as well, all wrapped up by a protective PVC sheath etc.. It doesn't cost a lot extra as its installed and manufactured at the same time as the power cable. Its this otical ring theyre tapping into with their wireless network.
One of the high street stores in the UK (Marks & Spencer) has just completed a pilot test at one of its stores. Worryingly the Department for Trade and Industry actually subsidised the scheme, even more worrying was of the 50 people who were intereview about RFID no one seemed to care or be aware of the technologies issues.5 5,39118147,00.htm
The scheme used intelligent tags that "hold just the number unique to each garment. When scanned against an M&S database, the tag would only give information related to the product's size, style or colour." Check out the full story at http://www.silicon.com/software/security/0,390246
Just off the top of my head Its probably quite difficult. All the RFID chip is doing is responding to an outside pulse and using the pulses energy to respond back. You would need a fairly, powerful EM (electromagentic) source to fry the thing which aren't too easy to get access to. It probably wouldn't be too clever if you wearing it as well. (unless of course you believe that mobiles phone transmitters aren't bad for you either)
:-)
Interestingly though i doubt many RFID tags would stand up to a hot wash, plenty of water with detergent and a big motor as an EM source nearby driving it might well fry it... Dunno the thought just occured to me - anyone got any ideas how physically tough the chips are?
The best way would probably be to have a big magnet at home or maybe move to a house under a supergrid power line
I see it as a question of the ease of tracking, I think it is basically a necessity of civilized society that if a criminal agency needs to track you it should be able to. At the moment its a non-trivial task to go about tracing someone who doesn't want to be found, so it only gets done in serious instances.
With the advent of all these new tracking systems, centralised global databases it data gathering becomes much easier, faster and more accessible. Its *this* that makes poorly thought out systems so dangerous as it vastly improves the potential its got to be abused.
What worries me the most is the fact that when government agencies go out to to contract usually the cheapest or their best buddy; and have a laughable record at dealing with sensitive information that isn't about them.
Have you been watching swordfish?? Actually you are pretty much on the right track, i used to work for a major oil contractor and whenever negotiations got a little *tough* i.e. the locals wouldn't do what was wanted. All the negotiators used to call it a day go back to the hotel for a few days and hey presto new locals to negotiate with... 'Where Vultures feast' is a very accurate book -its easy to be calm when your sitting on top of a mountain and having nothing better to do
I think they mean the pre-cursor to International Friend or Foe (IFF) technology used by planes in WWII. If i remember right, they started off with the same idea of using a passive inductive loop that would respond to a transmitter in the fighter.
This might just be word play, but i read it that the kid thought he was selling the whole buisness for $10k. Wouldn't that get him out of the fire to an extent?