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#70810 - 10/13/06 08:27 PM Tempest/faraday info  
JCooper  Offline
Member
Joined: Dec 2002
Posts: 228
Kendall Park, NJ USA
I can't I can justify the cost for this but I was trying to figure out just how I can turn my entire house into a faraday cage. I can line the walls with copper mesh, drive a whole bunch of ground rods, convert cable & telco over to fiber outside the house, but there is one piece I can't figure out, power.

My question is this, can you isloate utility power from an EMP?

I thought about a natural gas genset, fed with plastic pipe of course, inside the 'cage'. Would a simple isloation transformer provide true isolation?


Work Gear for Electricians and the Trades

#70811 - 10/13/06 08:29 PM Re: Tempest/faraday info  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
I just use tin foil bed sheets.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#70812 - 10/13/06 08:59 PM Re: Tempest/faraday info  
NJwirenut  Offline
Member
Joined: Sep 2001
Posts: 806
Bergen County, NJ
First of all, TEMPEST shielding and EMP suppression are not exactly the same thing.

TEMPEST has to do with reducing radiation FROM equipment which could be intercepted by someone on the outside. Involves a lot of heavy shielding, broadband filtering/bypassing, etc.

EMP suppression is for the protection of your equipment. It can be achieved by LC filtering and fast-acting impulse suppressors like these:
http://www.polyphaser.com/kommerce_productdata.aspx?search_val=NEMP&x=0&y=0

Yes, utility power can be bypassed and filtered where it enters a faraday cage. It is done all the time in screen rooms used for RF equipment testing.


#70813 - 10/13/06 11:37 PM Re: Tempest/faraday info  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
In response to a similar query.. "how can I protect my electronics from EMP?", I recall the following expert advice being given:

"Place them inside a steel ammo box. Ste this box on a block of wood, inside a larger ammo box. If the EMP still damages your electronics, you are way too close to ground zero."


#70814 - 10/14/06 02:51 PM Re: Tempest/faraday info  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
What are you trying to protect against. That will make the difference in what you need


Greg Fretwell

#70815 - 10/16/06 08:44 AM Re: Tempest/faraday info  
SteveFehr  Offline
Member
Joined: Mar 2005
Posts: 1,198
Chesapeake, VA
There's an unclassified army manual for EMP-proof facilities design, EP 1110-3-2. All your answers are in there [Linked Image] The amplitudes are completely different between EMP and TEMPEST and frequencies vary a little, but the level of attentuation and design for protection for both is practically identical.

To get 90dB attentuation, you can't just use tin foil, you have to use a significant thickness of steel or copper or another conductor, otherwise a significant portion of the EMP burst will transmit straighit through it and still come out the backside at reduced but dangerous levels. The thickness depends on the frequencies and desired level of protection, and of course the material being used- welded 1/4" carbon steel will provide this protection.

You can buy filters for power and communication lines that provide > 90dB protection.


#70816 - 10/16/06 11:29 AM Re: Tempest/faraday info  
Almost Fried  Offline
Member
Joined: Sep 2006
Posts: 98
Madison County, Ark. USA
There is a cave in Newton County, Arkansas for sale for about 1.5 Million that should suit your requirements. You can't hide from all of it, forever, and then there are telemarketers...


#70817 - 10/16/06 11:34 AM Re: Tempest/faraday info  
earlydean  Offline
Member
Joined: Dec 2003
Posts: 751
Griswold, CT, USA
Build your own with 4 foot thick reinforced concrete walls and ceiling, bonded to about 2 dozen ground rods. Power would be supplied by an on site generator, or a nearby set of batteries with inverter, which could be kept charged by the utility power.


Earl

#70818 - 10/16/06 10:36 PM Re: Tempest/faraday info  
RobbieD  Offline
Member
Joined: Feb 2003
Posts: 231
Canada



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