Tests are conducted to measure how effective metal garbage cans are at blocking high-frequency energy, such as that released by an high-altitude nuclear electromagnetic pulse (EMP). Tips are provided on how to greatly improve the shielding effectiveness.
Disaster Preparedness for EMP Attacks and Solar Storms– (book mentioned in the video).
Another EMP video by disasterprepper- EMP Introduction to EMP and Faraday Cages
Thank you, Whiskey-34 for sending this video over!
Well, it’s not TRESTLE or Dahlgren, but it’s effective and gets the message across. You have to love basic workbench scientific method. Tesla would be proud.
We have talked about EMP and trash can cages on TAPRN several times. this is the only video I have seen with data to support the idea. And as we see by the data, the can may not be as good as first believed. But with a little improvement can be effective. I ordered the book from Amazon and look forward to seeing the rest of his measurments.
Thank you polly-01 for posting it.
73 de whiskey-34
Cool vid. A good alternative to tape is to install a number of sheetmetal screws to connect the lid to the body. I’d like to see that tested. The most important aspect is to have a tight fitting lid to begin with.
No need to insulate items from the walls of the can nor to ground the can. Metal popcorn tins also work as long at the bottom and side seams are soldered. Again a tight fitting lid with bare metal to bare metal contact, plus screws or metal tape are the last step.
I ordered his book last year and it is good. He explains the calculation and theory behind it. I used to do a lot of shielding work a long time ago, but forgot most of it.
The most important thing is to minimize gaps as already said by Bradley and Hotel-04. I had to go look it back up again, and the source I found recommended keeping the aperture (gap or hole) no larger than 1/20 of the shortest wavelength (1/50 in the microwave region).
I just checked Bradley’s book and he says for the frequency range of 100 kHz to 1GHz (EMP frequency content), there should be no holes greater than 1/10 inch (2.5mm), which is more on the order of 1/100 wavelength if I ran the numbers right. He says that this is justified by understanding the frequency content of an EMP and the characteristics of a slot antenna.
And as Hotel-04 stated, contrary to what most of what is seen on the internet, a ground is not needed. It doesn’t hurt or help, except maybe to bleed off charge from the cage.
The faraday cage works because the garbage can’s electrons move and re-align themselves with the external electrical field (component of EMP), and create an opposite, neutralizing field inside the can. So, net E-field is zero inside the can.
Here are Bradley’s rules from the book:
– All seams and gaps must be conductively sealed
– No hole or gap should exist that is greater than 1/10 of an inch (2.5mm) (for EMP frequency content)
– Nothing conductive, such as a wire or antenna, should penetrate the enclosure
– Line the box with cardboard so that electronics do not come in contact with any foil on the inside
I used a 31 Gal can, spray foamed the inside, then put a 20 Gal can inside that. Once you tape the lids shut, good luck get a signal inside.
it makes me proud to read all the info you all are sharing ,,So many do not believe this is going to happen..But it’s better to be safe then sorry..
Is it a good idea to make a trashcan faraday cage and then take electronics and put them in a box and wrap that and seal it with tinfoil and then put that in an ammo can that is made to be a faraday cage and then finally all of that into the trashcan for the most shielding possible?
If done correctly that is three levels of shielding correct?
THE DIEHOLD PROJECT. I suggest everybody watch this guys videos on YouTube.
I tested my cans with and without faraday cloth, with every seam and the handle holes taped with the aluminum tape, with a heavy seam of aluminum around the top of the can which was fully Lined with cardboard. INSIDE 4-6 layers of faraday cloth or bag, a Midway walkie-talkie signal set to channel 1 at 3 feet did not penetrate for an audible response. All other layers of cloth failed the test. Another website indicated that would be a successful test if at 30 feet. Distance for the radio transmission did matter, (I could go further with fewer layers) so which is more realistic for a HEMP generated frequency? This cloth is extremely expensive.