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How to Test the Effectiveness of Different Homemade Faraday Cages


EMP Protection with Homemade Faraday Cages
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I feel we covered the theory of EMP in the last article, so now I want to link to some videos of the Homemade Faraday Cages experiments I have done trying to find the best system for protection of my personal equipment.

Like I said in the previous article, you hear a lot of internet commando ideas on Faraday cages, but you rarely see anyone actually test the cages they talk about. I did not build a EMP generator for obvious reasons, so I had to find a reasonable alternative.

For the tests I used a cell phone and a FMRS/GMRS handle talkie. Cellphones operate in the 850/900/1800/1900 MHz ranges at about .75 to 1 watt, a FRS/GMRS is around the 463 Mhz range at about 5 watts.

Neither of these are within the test ranges of the 1962 HEMP tests of 1 KHz to 100 MHz but they are within the range of later tests that show EMP ranges from 200 MHz – 5GHz and may be as high as 30-billion watts (depending on type, and distance from source).

I am not trying to protect my cellphone.  In a post EMP area, a cell phone would be useless (unless you have steel wool). If my cage cannot shield against cell phone transmission, then it is worthless against the much higher EMP.

I am NOT trying to protect the phone.  I am seeing if the cage can block the signal TO the phone

Please view the videos below to see some of the cage designs I tested. Personally I don’t rely on any of them, and just keep a few redundant items in them to make life easier.

I feel that in the event of a man made EMP attack, the few things I can store won’t balance with use verses cost, so I spend my resources on items to work around electrical dependence.

Besides the FEMA guidance I mentioned in the earlier article, you may want to visit this document:

Aluminum Foil

Mylar Bag

Popcorn Tin

Published inGeneral Building


  1. Don’t know much about EMPs, maybe you can enlighten me. What protections do the phone, internet service providers, cable, etc.. take to safeguard themselves from an EMP?

    • Not enough, its too expensive, and the infrastructure just isn’t there to keep enough backup parts. Pretty much they have some inline surge protectors, but that really doesn’t do anything for E1 type pulses.

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