On Wed, 12 Jul 1995, Doug Hughes wrote:
Go see Winn Schwartau talk about HERF guns sometime. He passed around a picture of a device for < US$500 that could crash any computer within 50 yards.. Then again, it isn't too good for the person firing the gun either.. (mega EM emissions).
That all depends on the power level, and the emission pattern of the device, and the frequency. I've been working within 10 feet of a dipole being fed by a 1kW amplifier before, and it didn't make me sterile (but it might've loosened a filling or two <grin>).
Agree!
The parts are available if you know what to get. a VERY enlightening and frightening presentation. I don't think he personally has built one. His presentation contained a presentation on TEMPEST emissions, and low level EM field effects on sensitive equipment problems too (a PBS documentary - a VERY compelling presentation of why you should never use walkman/CD players/radios/electronics equipment on airplanes if they say not to, and you value your life)
This sounds like absolute propoganda. If you do the calculations, you'll see that a 1 watt transmitter sitting 100 feet away from your target will generate an EMF less than that 1000kW ERP TV transmitter array you just flew over. If aircraft avionics were *that* sensitive, we'd have planes falling out of the sky, and we don't. Add to that the HF and VHF transmitting equipment in the cockpit, plus the microwave ovens in the fore and aft, PLUS the phones they have on the plane, and it adds up to a sizeable amount of RF bouncing around the cabin without you and your 2m talkie with it's 6 dB loss rubber duckie.
Now, if every passenger fired up their 2m talkies, that might pose a problem, but then again every passenger wouldn't be using one, would they?
Again, sounds like "we want to totally control your environment for your safety (actually, to minimize our liability)" crap.
If you saw that PBS documentary (they want $20,000 for rebroadcast by the way). It was an 87 or 88 or something like that. It would make you a believer. There was a lady in a van that whenever she used her cellular phone, her sun's breathing apparatus (lung impaired) went into alarm. There was another case at a hospital pre-natal care word near the main entrance to the hospital. Several occasions when a local bus loop went by, and the guy happened to be talking on the intercom of the bus, several of the units in the ward went into alarm and failed (they had a tough time tracking that one down by the way). Wheel chairs for handicapped people were sensitive. They held a cellular phone about a foot from a wheel chair control and it started spinning around and generally going out of control. (The guy's wheel chair had gone out of control and run him off a heavy slope once and he almost died. it was unproven whether it was electromagnetic or just a defect). This just goes to show that we live in a world of electromagnetic soup. We really don't know how it effects the body long term, or whether, having more mission or life critical electronics could be interacting with over devices. This was the theme of the program. Another example was on an airplane (several of them.. older ones mostly I believe) pilots would occassionally lose instruments (VLS, etc) when passengers would activate portable transistor radios and such. Particularly radios.. But there was another case involving a portable computer.. These cases have been documented. It's a good thing the plain wasn't on a landing approach during a storm, or things could've gone very bad very quickly. I heard about the portable computer via a different source. The guy kept turning his computer on. The instruments would do a little dance. The captain would tell the stewardess, she would tell the passenger, he would turn it off for a while. Then, he would turn it on and repeat.. Until finally he refused to turn it off, so they confiscated it and returned it at the end of the trip. Urban Legend? maybe.. Believe what you want, but investigate the reports before dissmissing it out of hand as propaganda. I'd rather stay alive than rely on "theoretically it shouldn't matter." :) Keep in mind that newer planes (767, 757) let you do anything you want while the plane is in flight (but now while landing or takeoff), so they probably build better instrumentation and cabin shielding into the planes these days. If they say keep it off, chances are they have a good reason.. If you find categorical evidence to the contrary, I'm sure I would be very relieved to see it posted here. (rather than wondering if somebody in one of the 30 rows ahead of me might decide he knows better) Disclaimer: I have absolutely no idea what kind of shielding goes into an airplane nor any knowledge of building practices in the airline industry, but that should be obvious. ;) Well, I've posted enough on this, and I don't have any evidence besides what I've seen and what I've heard from others. For all I know the entire documentary was botched (it was shown on an evening newsmagazine in the late 80's hosted by Connie Chung - British documentary). Now back to your regularly scheduled mailing list already in progress. -- ____________________________________________________________________________ Doug Hughes Engineering Network Services System/Net Admin Auburn University doug@eng.auburn.edu "Real programmers use cat > file.as"