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Real Life EMF Experiences?
ilander asks: "I've been looking to buy my first home recently and found one that seemed perfect. The one downside is that there are power lines directly overhead (in the yard) as well as a high tension power line tower in the empty lot in back, less than 200 feet away from the house.
So does anyone have any personal experience working/living near power lines? Aside from the possible health risks, which may or not exist (depending on who you ask), will I run into any problems with my monitors and TVs? What about DSL, cable and my 802.11b network? How about digital satellite reception?
Any help is appreciated!"
You may want to ask how it might impact your health. Google it to find articles like this one in Wired.
I lived 15 years or so 200 feet from high voltage lines. And 500 from a substation. My family and my neighbors are fine. Of course I post on Slashdot so I guess that answers you question. I don't think anything happens from being near them. I didn't even care about it when I found out something might happen.
Why don't you guys have friends or journals?
Inductance. An AC (alternating current) electric line will generate a changing magnetic field (magnetic field first goes in one direction, then the other).
You have a changing magnetic field. You create a circuit (albeit one at several megaohms) when you touch the light like that. Indeed, you make a big loop.
You can find the equations for inductance in any elementary physics book. Essentially, the faster the change in magnetic field, the larger the loop the circuit forms, the larger the magnetic field change per unit time (e.g. larger oscillating magnetic field), the higher the electromotive force (voltage) induced.
Note that emv ~ dB/dt * A (B and A are vectors). That is, assuming your circuit is a 2D object (e.g. circle), then you should orient your circuit such that the magnetic field is perpendicular to it. This will give you the maximum effect.
Again, refer to college physics textbooks for more information on the subject.
Synopsis: good for scare-mongering (but remember, scare mongering's Good when you agree with the goals of the scare-mongering (e.g. nuclear power dangers) and Bad when you don't (e.g. Bush's terrorism stuff)!) but otherwise fairly pointless, unless the induced voltages and/or B/E-fields are scientifically proven to be dangerous to humans. To my knowledge, it's currently a wash. Note that statistical data for a region is questionable, since many factors enter in! (The prime exampe for correlation-does-not-prove-causation amongst my professors is the study that showed that, the more electric poles per square mile, the higher the murder rate. (Of course, the primary factor is that the denser the electric poles, the more densely populated the region)).
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Given enough personal experience, all stereotypes are shallow.
Despite all the people who want to sue to make a buck, there is *no* scientific evidence that living near power lines, using cellphones, or sending your kids to a WiFi enabled school will hurt anyone.
I live less than 200 feet from high tension power lines and have never experenced any problems with the wireless network in my house.
The only real problem I had was putting an addition on my house. In my town, it is against bylaws to put a permanent structure closer than 100 feet from power lines. When my wife and I were in the process of putting one on we had to have our yard surveyed four times, and even then we had to change our plans. The foundation of the new addition is now 100' 1" away from the lines. You may want to think about this, or check your town bylaws if you plan on adding to the house in the future.
There's also a site called Power Line Facts that may be helpful. Like they say, go buy a power meter, then do another house inspection. If the meter's reading 4mG or higher, run away. Fast.
And what's Power Line safety without a blog?
Trolls lurk everywhere. Mod them down.
As a amateur radio operator I have heard people that have found radio interference being generated from overhead power lines. Most of the interference has been in the lower frequencies, low as in AM broadcast radio, HF amateur, maybe up to TV and FM broadcast. The causes were something like failing insulators, damaged transformers, and branches falling onto the wires. In most cases a call to the power company would result in a quick fix. It is unlikely to affect higher frequency devices such as WiFi, satellite TV, and cell phones.
One current concern is the possible use of Broadband over Power Lines (BPL). A form of BPL proposed to the FCC would occupy frequecies from 2Mhz to 80Mhz being carried down the medium and low voltage power lines. Since power lines were never intended to carry such high frequencies the amount of "leakage" is likely to be quite high. The leaked RF energy would likely cause all kinds of trouble for electronics in your home. Computer monitors, TVs, radios, etc. all have internal circuits that work at these frequencies and are unlikely to have sufficient shielding since BPL would be allowed much higher levels of leaked energy than seen previous if the law changes go into affect. More info can be found on the American Radio Relay League website (www.arrl.org).
If the powerlines run over that property, then most likely the power company has an easement, which roughly (I'm no lawyer) means that should something happen, they can wheel a crane into your backyard to do work, and you will have to live with it. And if they have to take the fence down, or nock out part of your house to get there, they will. (Though they will fix it later). You will really have to check this out with the local government, and it may not be that simple.
Another thing is that power lines make noise. It may not seem like much during the day, but it may drive you nuts at night.
I'd stay away from it for just those two reasons.
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