low frequency EM pulse

capybara · August 15th, 2002, 11:25 PM

what could case a low-frequency EM pulse that
1. was not audible like an explosion would be
2. caused a two-block power outage
3. stopped some cars dead in the street, but mainly older cars
(speculation: the newer cars have better shielded spark plug wires)
any guessses, links, or XPeriences as to what causes this?

(fwiw, this occurred last weekend in carlsbad, california
and our local power co., sdg+e, said it was a low-frequency
EM pulse)

nunyadam · August 16th, 2002, 12:32 AM

here's one site a quick search turned up.

http://www.iec.ch/zone/emc/emc_entry.htm

basicaly if it's electric it give off em radiation.

or if you go by what this guy says you could blame the russians.

http://www.elfis.net/elfol8/e8elfeeg1.htm

surreal · August 16th, 2002, 12:46 AM

Sounds like the movie.. The day the Earth Stood Still..
(OK I spent too much time in front of the tube as a kid

)

**Whir** · August 16th, 2002, 09:31 AM

I'm suprised it stopped more old cars than new. From what I gather (and it could be myth) newer cars are far more vulnerable to an EM pulse, as they are controlled by an ECM. Older cars (like my poor Monte Carlo) haven't got a computer to get killed. An EM pulse may disrupt the ignition system, but it wouldn't kill it like it would an ECM, since it's just a coil, a distributer, and some wires. There's nothing to kill. Your radio'd be gone though. That would suck.

It could be that the newer cars are shielded from things like EM interference (a violation of FCC laws?) and the ignition systems are indeed vulnerable in older, mechanically controlled cars.

There was a guy floating around that was a buddy of a buddy that was trying to develope a HERF (High Energy Radio Frequency) gun. Basically the same principle, but in a focused beam, rather than an explosive pulse. Point being, you point it at something, it stops working (great for police chases he figured - kinda shadey). I think they got a small version to work through walls on computers. I need one of these for work... MUAHAHA!!

-Whir

Edit: I think I decided to unlearn how to spell, but I'm too lazy to fix anything...

surreal · August 16th, 2002, 11:15 AM

Hmmm reading Whir's comments on the EM Pulse is trying to pull something from my memory..
Oh nevermind I found it.. It was an Xfiles episode.. can't remember what the issue was with it tho.. can anyone?

Wombat · August 16th, 2002, 12:50 PM

Wasn't that episode to do with the millitary testing sonar or something?

Paul

**Whir** · August 16th, 2002, 12:59 PM

James Bond: Goldeneye.

-Whir

DangerSeeker · August 16th, 2002, 02:04 PM

Sorry, that was my fault. My pulsewave ignition went out in my craft. I had to reboot the main fuel system before the ignition would reactivate, which causes a bit of an EMP ray from the exhaust...and I just happened to be overhead.

If I could find a PSWIG driver for Linux, I could get rid of this buggy Windows, and I wouldn't have that problem anymore.

shabeepk · April 4th, 2004, 09:14 PM

well i liked the way u ppl talk ...
n i just wanted to ask does anyone tell me how does EM pulse radioation stop things from working ?
or if anyone knows where, i can find such an info thats would be great ...
fanx

originel · April 4th, 2004, 11:00 PM

Quote:

(a violation of FCC laws?)

nah that's not against regs. actually if things weren't shielded a lot of electronics wouldn't work. The clause that states "this device must accept any incoming e/m" (paraphrased) basically means that it must be able to deal with any e/m in the air because all e/m in the air is (theoretically) regulated by the FCC and that they can't go complaining to the FCC about it.

basically the way E/M interference (it's not radiation fyi) works is through the relationship between eletric and magnetic waves. whenever you send current through a straight wire it will create an e/m field that runs in a circle around it like insulation on a cable. btw, this is how electric magnets work...they coil a piece of wire which focuses the e/m into a straight line. Well all of the e/m in the air adds up and the way e/m fields are created from current also works the other way around. so when these e/m fields hit wires in electronics they will induce a current in the wire. This can have many different effects, from overloading a line and causing the circuit to fry (only in extreme cases) or it can do other things like change the potential which can, for example, change a digital 1 to a 0 or vice versa and scramble the data. a lot of other things can happen depending on the device.