Building Your Own EMP Faraday Cage

[tinker]

Really great and extensive thoughts and ideas in reference to this subject.
ttabs: Excellent photos of the bonding to ground using clamps and ground rods - - I personally would have an extra heavy copper run to a plumbing clamp on the pipes too.
gil: Batteries are considered to be immune by all the test data that has been released to the public. I personally have high voltage caps in parallel with all my DC battery feeds so that any transcients are ensured to be absorbed in a momentary field surge. I figure, why take a chance, we only get one shot at protection.
cheers,
73 de Ian

[White Tiger]

Just found something from APN (American Preppers Network) regarding this topic:
From the link:

http://www.americanpreppersnetworkradionet.com/2013/02/a-primer-on-faraday-cages.html?utm_source=APN+Newsletter+for+week+of+Feb+24%2C+2013&utm_campaign=Constant+Contact+11-3-2012&utm_medium=email

"Can a Faraday cage have holes?
Yes, as long as the holes are small with respect to the wavelength of the incident electromagnetic wave. For example, a one GHz wave has a wavelength of 0.3 meters in free space. As long as the holes are significantly smaller than that dimension (i.e., a few millimeters), they won?t let in much of the incident wave. This is why fine conductive mesh can also be used for making a Faraday cage. In practice, the lid or door usually causes the most leakage. Taping the seam with conductive tape greatly reduces this leakage...."

[Geek]

APN is an out of control forum.  I wouldn't trust it.

[White Tiger]

APN is an out of control forum.  I wouldn't trust it.

I did not mean to sell the website - especially to anyone here. I refer to the science behind the article (as far as I understand it), which seems sound. I'll let the experts pass judgement though.

[Geek]

APN is an out of control forum.  I wouldn't trust it.

I did not mean to sell the website - especially to anyone here. I refer to the science behind the article (as far as I understand it), which seems sound. I'll let the experts pass judgement though.

I didn't take it that you were promoting the site, but my experience is that it is a place for the "moderators" to pontificate, but they don't always know what they are talking about and don't appreciate someone else providing useful information.  When they are wrong they are adamantly wrong.

[White Tiger]

Then I resubmit my post #45 ;-)

[Ken]

The phenomenon is actually sometimes referred to as the Carrington Effect after Richard Carrington who recorded the effects of the 1859 Coronal Mass Ejection.  Our engineering Faraday cages (actually rooms) were built of screen wire panels.  As has been pointed out, the door is the weak point.  The effectiveness of the cage depends upon the skin effect - high frequency (rapidly rising) electromagnetic energy actually travels only on the surface of a conductor.  So as long as your cage is properly constructed as a continuous conductor no energy will travel below the surface.  The need to insulate the contents and ground the cage are over-stated (good ideas, but probably not necessary - I'll let you know after the CME). I use military boxes of various types.  On all I have replaced the rubber seal with the tinned-copper braid commonly used for ground straps.  As has been pointed out, do not forget to remove the paint from both surfaces! EMP/CME knowledge consists of a lot of theory and less practical experience. Jerry Emanuelson seems to have the most up-to-date information on his web site already referenced here (http://www.futurescience.com/emp.html). The limited history does prove that the risk is REAL and that prudent individuals will prepare!

[s2man]

Thanks for the link, Ken.  That's a good article.  I pulled up my bookmarks and checked my favorite article on EMP protection.  Guess what? It from the same site, linked in your article.  http://www.futurescience.com/emp/emp-protection.html

Note to self: Still need to get ferrite beads to help protect the fridge and freezer from power surges...

[White Tiger]

I drilled a 1/2' hole in the concrete floor of my basement here and - using a fence post pounding device - drove in an 8' grounding rod.  Then it was just a simple matter of hooking it to the cabinet. 




Now that it's grounded - I then used some military foam sleeping pads cut to length as an insulator on the shelves .....

OK, ttabs (and anyone else using grounding straps on their Faraday Cage), I just read something on the link provided by Ken - and linked to by s2Man - that seemingly discounts the need for grounding to insulate your gear due to a solar storm or EMP:

http://www.futurescience.com/emp/emp-protection.html

"...Large professionally-built faraday cages need to be well-grounded, but for smaller faraday cages, such as you would use to shield a radio or a laptop computer, any wire running to a ground is likely to just function as an antenna, and possibly as a very efficient antenna for gathering EMP...

...For shielding small items like radios and other electronics equipment, use the nested faraday cage system of alternating foil (or screen) and plastic, and don't bother with the ground connection (unless you plan to physically bury your equipment).  EMP grounding gets very tricky, and the ordinary rules for grounding do not apply.  (Most high-power transmitter antennas are actually at a DC ground.)

Now, please keep in mind that I am still the least technical guy any of you will ever know...so help me understand if I've got this wrong...otherwise, Im not grounding a metal cabinet or a metal trash can, to protect items I plan to store inside...

[ttabs]

Sorry for the late reply - I'm not getting notifications via email from this website anymore to stay on top of my threads.   

I mentioned (and linked) to an article on page 1 that is a good read on EMP.  I went so far as to contact the author to discuss my Faraday set-up.  I too thought I'd get dinged on the grounding rod but he stated in my case, it was a plus.  Grounding is not necessary and in many ways can act as an antenna bringing in more energy onto the cage.  So his recommendation is to not use a grounding rod.   Also he mentioned that all painted surfaces need to be grounded for positive connection and that using doors presents a significant problem.  I have purchased some braided copper to line my doors so they make a positive connection.  To date, I have not done it yet. It's one of those 'rainy day' projects that's been put on the back burner.   

To date, the best, quickest, and easiest faraday cage I've seen is to buy a metal garbage can and line it with a thin foam sleeping pad.  I've done this also.  It's sloppy and awkward just dumping all your stuff in there but it will work well. 

Here's a link again to that article ....

http://www.futurescience.com/emp/emp-protection.html

[Geek]

Since you have used the garbage cans, what did you use to seal the lids?

[ttabs]

The lids are metal and make contact with the can.  It's sealed for purposes of a Faraday Cage. 

[Jim_Duncan]

Is it necessary to ground the garbage can in any way?

[RichardSinFWTX]

If it's sitting directly on something the concrete garage floor I wouldn't think so; but a little extra protection can't hurt.

[Bigguy49]

Been reading this post and had a thought on using the ammo cans , and that is what about using aluminum foil to cover the opening of the can then closing the can lid on top, if the paint was removed from the can body and the foil makes full contact with the can edge I think it just might do the job of shielding the contents