Forwarded from: Steven Hess <s_hessat_private> [This is the last posting on the E-Bomb thread. - WK] -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The technology looks like the same as for lightning protection. I think the protection would be similar. Lightning does damage not only by striking the component electrical path, but by generating the same kind of high strength EMP - the bolt is comprised of several strokes, and each one generates EMF lines of force. When these moving fields cut through a conductor, a (lower voltage) is generated in the conductor, perhaps spikes of several hundred volts or so. The current state of lighting protection is to : 1. shunt spikes to ground on conductors with MOSFET or similar variable semiconductors. (you see a cheap version in a surge supressed power strip) 2. ground chassis and cases to isolate from EMP and arcs. 3. Signal isolation via fiber optic. 4. Star Grounding system to prevent conductance between different ground systems. (Racks should be grounded on a separate system from AC electrical grounds, and should be bonded only at the Ground/Neutral connection point). The "faraday cage" mentioned is the same as placing equipment in a grounded case, with the exception that the cage has "holes" in it that depending on frequency, offer a path for the cage to leak RF in. The cage should work, though better than a grounded case if the following is true - If the EMP pulse is very low frequency, and the Faraday cage is made up of higher current carrying capability. We use different kinds of grounding depending on what is to be shunted, four ought cable for low frequency, copper flashing for high frequency. My experience is with Television Broadcast towers and transmitters, and the associated broadcast equipment, which get hit with lightning a lot. Most of the damaged systems are not struck directly, but surged on their power, data, video, audio, or phone connections. A UPS can help, if it incorporates surge supression, and it isolates the power from the line. Phone line supressors work to a certain extent, but nothing I have found keeps everything working all the time - even the fiber optic units can sacrifice themselves on the "outside" connection. Steven Hess Assistant Chief Engineer WTTA TV Tampa (lightning capital of the world - no kidding) > -----Original Message----- > From: owner-isnat_private [mailto:owner-isnat_private]On > Behalf Of InfoSec News > Sent: Sunday, September 30, 2001 6:12 AM > To: isnat_private > Subject: Re: [ISN] E-BOMB > > > Forwarded from: Darren Reed <darrenrat_private> > > In some email I received from InfoSec News, sie wrote: > > Forwarded from: Russell Coker <russellat_private> > > > > On Fri, 21 Sep 2001 09:39, you wrote: > > > http://popularmechanics.com/science/military/2001/9/e-bomb/print > > > .phtml > > > > > > BY JIM WILSON > > > September 2001 > > > > > > In the blink of an eye, electromagnetic bombs could throw > > > civilization back 200 years. And terrorists can build them for > > > $400. > > > > This is a very interesting article, but it fails to mention one > > crucial point. What is the effect of an EMP weapon on magnetic > > storage? > > Somewhere in that article, it mentions "magnetic field", if I > recall correctly. I don't remember enough physics to recall the > interfaction between faraday cages and magnetic fields (of what > strength even?). > > Elsewhere on this topic mention of faraday cages has been made. > > On that topic someone said that isn't enough. The most important > point is you _cannot_ have _any_ wires going in or out of that > faraday cage - it needs to be completely eletrically isolated. No > data leads, no power leads going in or out of it that contain a > conductor. For data, this is an easy problem: fibre. 100BaseFX, > ATM, GigE, FDDI come to mind. But how do you fix the problem of > power? Does anyone know of any mechanical (or other) means of > getting power into/out of a > faraday cage without there being any conductive path through ? > Where do you go to buy such equipment (assuming it is unclassified) > ? Can you buy, for example, laser based power couplers ? (power > in one > side, laser beam over 6 inces, power out the other side). > > I'm almost 100% sure a UPS is not going to save you. Their > reaction times are too slow for the rise generated by an E-Bomb and > even then some of them will switch out to save themselves and your > equipment goes "boom". > > Darren > > > > - > ISN is currently hosted by Attrition.org > > To unsubscribe email majordomoat_private with 'unsubscribe > isn' in the BODY > of the mail. -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQA/AwUBO7dTViIuNDPeTcEfEQJXbgCdHav6maZ7lyYqE/+Ty09jVY4Wr10AoJY6 SvWOv48hwwUG+/06XsFssLi/ =lDAm -----END PGP SIGNATURE----- - ISN is currently hosted by Attrition.org To unsubscribe email majordomoat_private with 'unsubscribe isn' in the BODY of the mail.
This archive was generated by hypermail 2b30 : Mon Oct 01 2001 - 13:46:25 PDT