Wow first person I have seen that had real test equipment instrumentation data experience and knowledge ,,,,all of which seem to be in very short supply these days, Thanks so much for taking the time to do this for the rest of us,
I know this is an older video but I am revisiting it. TY for making these videos. This may sound trivial but people must check the handles on these garbage cans. The newer ones are not welded on. There are now 2 slits that the handle slips into which leave an opening. Might want to cover the inside of the top near the handle with alum tape as well.
Great help! At last scientific analysis of EMP protection for the layman. I'm moving my prepardness onto EMP's and knowing that the Dri-Shield 3400 works very well finally gets me going in the right direction. I'll probably get some type of properly sealed metal container to put the sealed up bag into for added protection. Really appreciated this! Superb.
not quite reliable test tho. testing in 499-500mhz range with nowhere near the power levels of a nuke EMP blast which would effectively be in the 15-250mhz range.
@@vaughanmontgomery3434 per a PDF I saw online (will try and link if find again) from California Institute of Tech. Prof., N-EMP would be around max. 100mhz...
I didn't think the chance of an EMP is very high, but since I had to store my electronic preparedness gear anyway, I figured why not organize it together and use a makeshift cage. Your vid really helped me see some additional steps I need to take with the tape and the right bags. Thanks for the hard work and for sharing.
i had near miss of lightning strike and even a computer laptop that had no connections to power or internet cable got taken out as did many things in house including the new refrigerators thermostat board
Chinese balloons being shot down all over the country, with strange devices attached to them. Yup, time to go see the EMP DOCTOR !!! A great video, and SO relevant all these years later. Thanks Doc !
Great video! I've heard there is another potential point of leakage with a galvanized trash can - the side seams are usually only spot welded in a few places which could allow energy thru the gaps. Have you ever done tests with the side seam taped?
No, I haven't taped the side seams. I think the steel is folded over running along the vertical seam, but let me double check. Obviously a long intermittently welded seam would be a good source of leakage. Will check and reply back.
It's important for people to think about electricity and fuel needs, home generators, battery backups and any fuel alternatives in case of any emergencies like electricity could go out for weeks or months at a time.
During an EMP will anything metal heat up, like those induction stoves? If so, would it be a good idea to line the can with heat resistant material i.e. use kiln insulation?
Really appreciate the professional evaluation of this technique. I have a question about grounding. Would it be prudent to ground the can? Would that help? One other thing would it help to wrap your products in bubble wrap to help insulate them from the can?
Everything I’ve come across says yes to both questions. -Ground gives a place for that energy to go. -Every layer helps. You can inexpensively do it with cardboard boxes wrapped in 3mil foil tape. Like Russian Faraday Nesting Dolls inside the sealed metal container…that is grounded.
Can I assume that using a bag and trash can together would offer best protection? Also, what recommendation for solar panels for recharging solar generators?
I dont know if anyone mentioned this, But I noticed on a garbage can we use to hold our chicken feed, it has a loose fitting handle you can probably see daylight where the handle is inserted to the lid and the tab is bent to kkep it in place. Perhaps some tape can help there as well.
Question, if you put a trashcan inside another trashcan, use Faraday tape to seal all the seams on both, do you think that will be much better than just a single can? Will that introduce any other issues?
Great job sir, in my own research I have concluded that if I test a VHF handheld two-way radio capable of opening the squelch at -120 dbm then wrapped in aluminum foil that it will NOT open up when a like kind transmitter putting out around +36 dbm is used near the UUT, like your example it is important to seal the edges very well.
Considering people having anything from hurricane kits to prepper closets, why hasn't there been anything on using canning pots (food preservation like boiling mason jars) and camping cast iron and all metal stove top cooking pots/lids... or aluminum serving containers be used in this matter? Some may seal better than others, but we may already have items in our homes that could be storing items in them instead of sitting empty on a shelf.
Can you use a copper braid like the kind you’d find in automotive applications as a gasket? Maybe even solder it to the ammo/trash can? How important is the foam? I’m trying to make my own gaskets and struggling
Please compare your top-notch Rohde & Schwarz spectrum analyzer against an Aaronia model. Both are far out of my price range, but I would love to know how well Aaronia competes.
I have an old vintage galvanized steel trash can I lined with aluminum foil on the inside walls and lid. I guess all I gotta do is set some tape in there to prep for the worst case scenario. I wonder how much more shielding the foil adds...:
LED flashlights are generally susceptible because they use solid-state electronics. I recommend storing them in a Faraday cage (or EMP bag) for that reason.
Good Video. I have a galvinized can on my back deck for trash bags. It always gets wet inside after rain as the top and side handles leak. May want to tape the can inside or solder the handle holes.
The cans aren't water tight, but surprisingly, the small holes don't affect the shielding much at all. I do a fun experiment sometimes when I teach class where we drill holes in a metal can and watch the shielding degrade. It take a lot of holes to compromise the shielding. But if you cut a long narrow slot in the can, the shielding is lost very quickly. It's the longest dimension of the hole that matters.
disasterprepper Thanks for the reply and the info. FYI I have it triple taped with aluminum sticky tape. Now if I could just find a way to disrupt the flight path of those pesky drones flying above my house. :)
Insulating the interior is fine to do. It's usually not necessary because most electronics already are in plastic enclosures, but it doesn't hurt anything.
Not sure if you can respond to my questions, but I really enjoyed this video I just first time watched, thankyou for the info Ok, I have an entirely aluminum metal rv horse trailer with living quarters(a Lakota colt). I was thinking of sealing all windows with aluminum and all joint areas with aluminum tape to create it into a faraday cage. I think it will work. Question is, do I need to put in a grounding rod? And when I finish and aluminum tape the main door on the outside will the tape stay on with rain falling on it or do I then need to put plastic over to protect the tape?
If you want to double bag do you need to have the first bag covered with something like a paper bag to insulate it from the second or just double bag one inside the other ? Thank you so much for your videos , that are very helpful to understand shielding.
Quick question.. does the gauge of steel effect this much. I'm going to use this steel drum that is much heavier than the trash can. If sealed properly..will the heavier steel help?
I understand the concern for grid damage from a CME. However, an EMP from a Neutron bomb would be the precursor to a far worse problem than a burned out generator. Personally I would want to be at ground zero.
I have access to metal grease drums. Much thicker than a trash can. I would think they would be very good as a cage against an emp. Of course sealed with tape.
Thank you for making this video. My question is how much shielding is necessary to protect the electronics that I would put in a container? 50 db? 75 db? 100? or more? your creating a electronic signal an blocking it but your signal isnt really comparable to say a small to medium size emp, or is it? thank you.
Hi Patrick, if you run the numbers, most folks conclude that 50 dB is adequate to protect from an EMP. That reduces the field by 99.7%. Some would point out that if you look at MIL-STD-188-125, you'll find an 80 dB requirement (99.99% reduction). Folks can make their own decision, but in my assessment nearly anything would survive with 50 dB of shielding. As for my testing, I'm not determining survivability to an EMP, but rather shielding effectiveness. I sweep through the frequency spectrum of an EMP to determine the shielding effectiveness, which is standard practice. If a configuration can give 50+ dB across all frequencies, it will give 50+ dB reduction of an EMP. The difference in maximum field levels of a small, medium, or "super" EMP is only a handful of dB, so it doesn't really change the shielding requirements.
It always stays a chance game depending on how close the EMP impact will be. Even a lousy shielding may protect your data e.g. at 70km distance of a nuke that else would erase them in 100km distance.
I am wondering if you suggest putting the equipment into the emp bag and then into the sealed garbage can, or if the bag alone is sufficient protection. I purchased several bags from your site today and would like to know if I should put them in garbage cans, too. Thank you so much for your invaluable information.
Hi Monica, first thanks for your purchase. As far as the bags, they provide about 99.7% reduction in electric field, which is enough to protect nearly any electronics. Some people either double bag or use a Faraday cage (trash can) for a second layer of protection, but it's really not necessary.
My cans are lined with wood and the lids are screwed and duct taped on. The cans are grounded and items in the cab are shielded by Dri Shield bags. Things like SW receivers and charge controllers. A full gamut of auto fuses and circuit breakers. Of course extra Walkie talkies
Dr., if I sent you some material, could you test it? Smallest workable dimensions for a box to be tested would be best as I don't have a ton of it. Also can you tell me what material(s) will block 5 G?
When I do the testing, the container has to be large enough to hold my spectrum analyzer. See my video of the large ammo can, which is about the size I would need to test something. I don't normally test other people's materials because, as you can imagine, it would be an endless job. I have a few times as special consulting activities, but I charge for my time. As for what would block 5 GHz, any conductor would as long as it doesn't have any seams or holes that approach a half of a mm in size.
When properly sealed, the trash cans provide excellent shielding. You can either tape around the lid with conductive tape (cheap but a bit of a hassle to get in/out) or use a conductive gasket around the sidewall of the lid (more expensive but convenient).
I am mostly concerned about family data..docs..pictures, videos, stored in few teradisk which are constantly running.. i guess if i were to sealed them in a dri-shield bag they would overheat as the bags are small. Could i get enough protection from a cage made with copper mash which then i could cover with the material of the dri-shield bags properly sealed of course..
A CME would affect satellites, radio communications, and the power grid (as well as things attached to it), but it wouldn't damage small free-standing electronics.
Do you have any test data for using a Dri Shield 3400 bag inside of a sealed aluminum trash can? I purchased your book but it does not address the layered effect. Should someone line the can with non conductive layer cardboard, carpet padding etc?
I have tested the two combined, but it is greater than my test equipment can measure. Typically, you can assume the protections roughly add (i.e., 50 dB + 40 dB = 90 dB).
I would to know how much emf can pass through a seam between a painted steel surface and aluminum foil taped to the surface with a few bits of gaffers or regular duct tape. I have my guns in a Fort Know safe made of 10 gauge steel. I then cover the EMP resistant Sargent & Greenleaf digital electronic lock with a stainless steel bowl, which I then cover over with aluminum foil. The aluminum foil extends about 3-4 inches beyond the border of the lock and is taped down using regular duct or gaffers tape. This arrangement makes it relatively easy to gain access and should offer some level of additional protection to the lock so that in case of an EMP I won't be locked out of my safe. Judging from this video it appears the trash can allows considerable EMF to pass through the small gap around the lid. This would be valuable to know for the many gun owners that worry about this issue.
Can you get these testing items at the Dollar store? LOL, just a tad expensive and technical for the average Joe... is this a home-made anechoic chamber your in?
Yes, it's possible by lining the walls, floor, door, and ceiling with aluminum foil. It takes some work though, and you have to pay special attention around the door. I have a photo of a room I created this way in my EMP preparedness book.
I lined my garbage can with some carpet padding. Is there any problem with this or should I have just used cardboard? I realize there is no emp benefit but I wanted a nice lining to keep stuff secure.
No. It's asked quite often, but grounding a Faraday cage doesn't help the shielding effectiveness. Grounding becomes important for shielding in other applications but not with Faraday cages.
I haven't seen all your video's yet but does perforated metal work better then aluminum screen? The holes in the perforated metal are 3/32 of an inch which is smaller then the holes in a microwave. Also in making a faraday cage, if you use both materials can you just sandwich them together are do they have to be separated with separate earth grounds?
I haven't tested perforated metal or aluminum screen, so I can't comment on which would be better. The hole size (longest diagonal distance) has a strong effect on the shielding effectiveness, but so does how well the weave of metal interconnects. If you make a multi-layer Faraday cage, you'd want an insulating layer (air is fine) in between them. In general, Faraday cages do not need to be grounded, although it likely wouldn't hurt the shielding either.
If you were to use the EMP bags on your website and put them inside of the trash can sealed with tape would the effect be even better shielding or is it ineffective?
Yes, layering like this is even more effective. It almost adds... so if the bags provide 50 dB of protection, and the can provides 40 dB, you might get close to 90 dB when using both.
Thank you for clarifying. I will be buying the bags on your site on my next payday. I kind of thought it would be more protection but I'm really happy to see that it almost doubles. Thank you for your time and videos.
@disasterprepper I have a question. Could you try to protect a SSD in such a metal container, put some Data on it, making sha256 checksums of the data and then try to destroy the SSD with an EMP? I would be interested to see, if a such protected SSD might survive that.
Creating an actual EMP is very difficult. It requires a full EMP simulator, which I don't have. I test at lower levels and measure the effective shielding.
There's no need to use a Faraday cage for solar events, only for EMPs. Solar events have much lower frequency content that doesn't couple well into small-scale electronics. The big concern for solar events is damage to things connected to long conductors (such as the electrical grid). But yes, for an EMP, putting items in these EMP bags does a good job of protecting them. You can double up by then putting those bags into a metal trash can if you like. It will provide additional shielding. My assessment, however, is that good quality bags would almost certainly be enough by themselves.
You can line the can with an insulative material. It can make it easier to store items inside, although it may not be required (depending on what you store). The insulating material won't affect shielding, but it can keep anything metal on the electronic items from touching the inside of the can.
Hi Doc... very much enjoyed the video, really informative and comprehensive, nice work. Here's a question for you, or anyone else out there who might know. I have a 40' shipping container which I use as a garage for my 4x4. Would the container behave as a Faraday cage in the event of an emp and, as it is resting directly on 8 concrete plinths, would it be sensible to earth it with copper pipe, or earthing cable ? Would be great to have a heads-up on it. Best regards.
It's on my to do list to test a shipping container. My guess is that it would do a decent job of shielding items, perhaps 20-30 dB of protection. The obvious leakage points would be around the doors and along any unsealed seams. Once I test a container, I'll be sure to post my findings.
Hi again, Doc... that's great, thanks for the swift reply. Problems with leakage around the door seals makes sense. As for a future video, if you do run a test on containers it'd be superb. As you know, there are so many folks now using them for storage that it would be really reassuring to have some form of definitive evidence of just how safe they'd be in the event of a pulse. Also, if you do have any thoughts on how to remedy the door-seal problem, that would be 100% good news. Anyway, thanks again for the reply. Stay safe, and best wishes to you. Regards, cuhurun.
Dr. Bradley, It's a very informative video and well done experiment! It's great to have this resource as there is quite a bit of speculation online about EMP shielding. I very much appreciate that you have actual lab equipment and follow rigorous methods to give us this high quality information. A question I have is regarding the use of metal trashcans (or any metal container) with some kind of gasket to avoid having to un-tape and re-tape when opening/closing the can/container. You allude to the use of gaskets in the video. What materials can be used for that? One thing I don't understand completely, which might help in being creative with a solution, is the physics of the trashcan rim "leak". Do you cover this in any of your source materials? Do you hypothesize that if the can lid were forced shut tighter causing more metal to touch, for example with some kind of lever or screw type clamping mechanism, this would improve the shielding characteristics? Thanks!
Hi Ken, all good questions. The thin seam (even partial seam) around the lid can leak significant energy. That's why we tape it with conductive tape. You could use a metal gasketing material (search EMI gasket). You could even make your own out of something conductive. Some folks use EMP bags (see disasterpreparer.com/emp-bags) inside the can, and leave the can untaped.
It's a standard shield room by ETS Lindgren. They put them up for RF test companies. You can also buy more ad hoc structures, such as RF tents, that work well.
Thanks for this great video! I have a question, what if you put your gear inside a 3400 bag, and then inside a non conductive box and then put that box inside an other 3400 bag? Would that not be better since the to shields don't touch or conduct each others EMP?
Okay great, thanks! Would it give a significant better protection to have two 3400 bags stacked? Am looking for 100-120 dB protection for some ESD and RF sensitive gear.
How well does the trash can work if electronic items are placed inside sealed EMP bags then placed inside a grounded metal trash can sealed with foil? Thanks
Hi Doc can you show what the best way to build a Faraday cage for a bed? Also could one hook up a grounding sheet while being in a Faraday Cage sleeping?
If you're looking for a way to block high-frequency RF energy, you could hang a canopy over the bed using sheer conductive cloth. It sort of looks like mosquito netting. Likewise, if you're worried about energy coming up from underneath you, you could put a layer of conductive cloth under the mattress. I know one lady who did this and said that it helped her quite a bit.
Sleeping always in a zero field of a faraday cage is unhealthy because the body needs the natural DC electric field. I have only the side to the neighbouring wall next to the bed shielded (overleaping aluminium strips) and have a metallized roller blind against the mobile radio mast.
What about the thickness of the shielding material? I've read up about the Skin effect, could a higher powered pulse like an EMP instead of your test rig be able to bleed through the conductor due to skin effect? (Atleast for the lower frequencies like
Skin effect is the term used to describe the tendency for high frequency signals to "crowd" to the surface of conductors. And yes, at very low frequencies, the formulas yield large skin depth values. That said, it's really not relevant for low frequency radiated wave energy (i.e., 100 kHz) because the wavelength of such signals is so long that the energy won't couple well into the conductive surfaces of a small object (like a trash can or EMP bag). Consider that the wavelength of a 100 kHz signal is roughly 3,000 meters. That means that it would need a conductor perhaps 300 meters long to couple into without significant loss.
Another question not related to faraday cages if you don't mind. I've heard so many conflicting opinions about standard solar panels and whether they are vulnerable to emp damage or not. Could you share you opinion on this?
No one knows for certain, but the best analysis seems to suggest that the panels themselves would likely survive, but the controllers and diodes would be prone to damage.
No, we tested many times, and ground the cans made no difference in shielding. The reason is that we're not in the near field of the source (that's technical jargon for grounding doesn't really matter in this case).
Here's my name on this comment. I like and appreciate you and your work. You're my Go-too EMP person. I ordered one of you EMP sensors a few weeks ago. HOW ARE THEY COMING AS FAR AS BEING READY TO SHIP?
Hi there, you mention the 3400 line of dri shield bags, I noticed there is a 3700 line as well. Would I be able to rightfully assume the 3700 is 1 step above the 3400? Any answer would be greatly appreciated!
No, not necessarily. The bags vary in material, durability, translucentness, etc. Of the ones I tried (about a dozen types), I like the Dri-Shield 3400 the best. All of the Dri-shield bags did well except for the 2700, which is very slippery and hard to seal well.
I would think that the smart meter is in the near field of the offending signal, and would therefore, normally be grounded. When in the near field, grounding helps to provide a conductive surface on which to terminate the electric field lines.
Something I've wondered for a while - would a heavy gauge steel "job tool box" provide any shielding if *not* taped? (assuming it was grounded and the electronic devices inside are isolated via non-conductive containers...) It is not practical for me to store most of my electronics in a sealed (tapped) trashcan as most of them I would desire to store for an emergency I also regularly use and cannot afford spares for to set aside. I'm hoping find something that could provide some degree of protection, possibly enhanced by being tucked away in the back corner of my underground basement, and might also provide some protection and also some degree of accessibility. Thank you for any thoughts on this.
Hi Calvin, lots of people have converted tool boxes and truck boxes to Faraday cages. But they usually install gaskets around the inside lid to make a tight RF seal. You have to pay attention to any seam to get good shielding.
My galvanized can has two vertical seams opposite one another on the body of the can. Should they be taped over, and if so, does it matter if they are taped on the inside or the outside. There are also perforations where the handles are fastened and where the lid handle is fastened. Are these small perforations of consequence. Thanks in advance for any info.
The seams on mine are folded metal, so there was no appreciable leakage. If you're worried about yours, you could certainly run a wide strip of conductive tape. It doesn't matter if on the inside or out. As for the small holes around the handle, they won't leak enough RF energy to bother with.
Instead of a spectrum analyzer could you use two way radios, or even 5GHz or 2.4GHz Wi-Fi networks, and see if a connection can still be established?. Of course the Wi-Fi router would have its own power source.
Hi Tim, if I get a chance, I will show how grounding affects the overall shielding. It won't actually make any measurable difference for a Faraday cage. It would, of course, be critically important if we were trying to shunt away energy, such as with a lightning strike.
Wow first person I have seen that had real test equipment instrumentation data experience and knowledge ,,,,all of which seem to be in very short supply these days, Thanks so much for taking the time to do this for the rest of us,
Thanks Mark. I appreciate the kind words.
WOW I wouldn't have thought the tape would've made that much difference. AMAZING
I know this is an older video but I am revisiting it. TY for making these videos. This may sound trivial but people must check the handles on these garbage cans. The newer ones are not welded on. There are now 2 slits that the handle slips into which leave an opening. Might want to cover the inside of the top near the handle with alum tape as well.
Essentially, the non welded handles are an antenna into the cage. :\
done!
How much good would wrapping the device with alum foil do?
Great help! At last scientific analysis of EMP protection for the layman.
I'm moving my prepardness onto EMP's and knowing that the Dri-Shield 3400 works very well finally gets me going in the right direction. I'll probably get some type of properly sealed metal container to put the sealed up bag into for added protection.
Really appreciated this! Superb.
not quite reliable test tho. testing in 499-500mhz range with nowhere near the power levels of a nuke EMP blast which would effectively be in the 15-250mhz range.
@@vaughanmontgomery3434 per a PDF I saw online (will try and link if find again) from California Institute of Tech. Prof., N-EMP would be around max. 100mhz...
It's currently March 6, 2022 and I'm watching all of these videos!!
I didn't think the chance of an EMP is very high, but since I had to store my electronic preparedness gear anyway, I figured why not organize it together and use a makeshift cage. Your vid really helped me see some additional steps I need to take with the tape and the right bags. Thanks for the hard work and for sharing.
Sure thing. I'm glad that they're helpful.
i had near miss of lightning strike and even a computer laptop that had no connections to power or internet cable
got taken out as did many things in house including the new refrigerators thermostat board
Chinese balloons being shot down all over the country, with strange devices attached to them. Yup, time to go see the EMP DOCTOR !!! A great video, and SO relevant all these years later. Thanks Doc !
Tremendous information and nicely produced. Thank you!
Thank you.
Very interesting, informative and worthwhile video.
Thank you Dr. Bradley for explaining how a faraday cage works and how to make one.
You're most welcome.
It would have been interesting to combine the bag with the garbage can to see the combined effectiveness. Good video.
was thinking the same
excellent video explaining what does and does not work well. Thank you for taking the time to share your knowledge with us lay persons.
Thanks. Glad it was helpful.
Just found your channel through this video and im glad to see you're still uploading. Very helpful
Thank you for sharing your knowledge and expertise.
I fucking love you. I'm not too much of a prepper, but I love how you took the effort to test this.
Great video! I've heard there is another potential point of leakage with a galvanized trash can - the side seams are usually only spot welded in a few places which could allow energy thru the gaps. Have you ever done tests with the side seam taped?
No, I haven't taped the side seams. I think the steel is folded over running along the vertical seam, but let me double check. Obviously a long intermittently welded seam would be a good source of leakage. Will check and reply back.
Any update on this question?
@@disasterprepper I also read the holes where the handles are attached are leak sources, as well.
Great Production Level & Information.
Thanks Bruce.
It's important for people to think about electricity and fuel needs, home generators, battery backups and any fuel alternatives in case of any emergencies like electricity could go out for weeks or months at a time.
During an EMP will anything metal heat up, like those induction stoves? If so, would it be a good idea to line the can with heat resistant material i.e. use kiln insulation?
Really appreciate the professional evaluation of this technique. I have a question about grounding. Would it be prudent to ground the can? Would that help? One other thing would it help to wrap your products in bubble wrap to help insulate them from the can?
Everything I’ve come across says yes to both questions.
-Ground gives a place for that energy to go.
-Every layer helps. You can inexpensively do it with cardboard boxes wrapped in 3mil foil tape.
Like Russian Faraday Nesting Dolls inside the sealed metal container…that is grounded.
No, It is a Faraday cage. You don't ground them. If anything, grounding them will reduce the effectiveness.
Can I assume that using a bag and trash can together would offer best protection? Also, what recommendation for solar panels for recharging solar generators?
I dont know if anyone mentioned this, But I noticed on a garbage can we use to hold our chicken feed, it has a loose fitting handle you can probably see daylight where the handle is inserted to the lid and the tab is bent to kkep it in place. Perhaps some tape can help there as well.
Question, if you put a trashcan inside another trashcan, use Faraday tape to seal all the seams on both, do you think that will be much better than just a single can? Will that introduce any other issues?
great video man! i think it's great to see you do experiments i'd like to do, keep up the good work brother!
Great job sir, in my own research I have concluded that if I test a VHF handheld two-way radio capable of opening the squelch at -120 dbm then wrapped in aluminum foil that it will NOT open up when a like kind transmitter putting out around +36 dbm is used near the UUT, like your example it is important to seal the edges very well.
thank you for sharing your knowledge much appreciated
i wonder if the mylar bags used for 3dprinter filament spools would work well
So does the galvanized trash can work if sealed against EMP? Didn't really hear you say if it was effective or not.
Considering people having anything from hurricane kits to prepper closets, why hasn't there been anything on using canning pots (food preservation like boiling mason jars) and camping cast iron and all metal stove top cooking pots/lids... or aluminum serving containers be used in this matter? Some may seal better than others, but we may already have items in our homes that could be storing items in them instead of sitting empty on a shelf.
Well done Doc!
is there a difference in emp shielding between galvanized and non-galvanized steel ?
Can you use a copper braid like the kind you’d find in automotive applications as a gasket? Maybe even solder it to the ammo/trash can? How important is the foam? I’m trying to make my own gaskets and struggling
Please compare your top-notch Rohde & Schwarz spectrum analyzer against an Aaronia model. Both are far out of my price range, but I would love to know how well Aaronia competes.
I have an old vintage galvanized steel trash can I lined with aluminum foil on the inside walls and lid. I guess all I gotta do is set some tape in there to prep for the worst case scenario. I wonder how much more shielding the foil adds...:
Wow, good to know particularly about the trash can. Have you ever tested mylar food storage bags or mylar emergency blankets? Thanks.
Thank You empdoctor!
You're most welcome.
How about putting your item inside the antistatic bag and then putting that inside the sealed garbage can?
Layering like that is done quite often. It greatly improves the shielding. You can easily get 80-90 dB if you do it carefully.
@@disasterprepper Thanks, Doc.
I hope you are still looking and answering questions. Will LED flashlights survive an EMP event?
LED flashlights are generally susceptible because they use solid-state electronics. I recommend storing them in a Faraday cage (or EMP bag) for that reason.
Some people use cardboard inside their can so will heavy duty construction trash bags work also?
Good Video. I have a galvinized can on my back deck for trash bags. It always gets wet inside after rain as the top and side handles leak. May want to tape the can inside or solder the handle holes.
The cans aren't water tight, but surprisingly, the small holes don't affect the shielding much at all. I do a fun experiment sometimes when I teach class where we drill holes in a metal can and watch the shielding degrade. It take a lot of holes to compromise the shielding. But if you cut a long narrow slot in the can, the shielding is lost very quickly. It's the longest dimension of the hole that matters.
Great vid. TY. I taped my can like you did. Will that be good enough for my emergency radio to survive an EMP?
Yes, it should be. If you're really concerned about it, you can put it into an EMP bag and then store that in the trash can.
disasterprepper
Thanks for the reply and the info. FYI I have it triple taped with aluminum sticky tape. Now if I could just find a way to disrupt the flight path of those pesky drones flying above my house. :)
is there something special about galvanized steel, or can i use a steel 55 gallon coated drum with a locking ring to hold top on?
Would insulating the inside of the can and providing a ground path from the can help?
Insulating the interior is fine to do. It's usually not necessary because most electronics already are in plastic enclosures, but it doesn't hurt anything.
Not sure if you can respond to my questions, but I really enjoyed this video I just first time watched, thankyou for the info
Ok, I have an entirely aluminum metal rv horse trailer with living quarters(a Lakota colt). I was thinking of sealing all windows with aluminum and all joint areas with aluminum tape to create it into a faraday cage. I think it will work. Question is, do I need to put in a grounding rod? And when I finish and aluminum tape the main door on the outside will the tape stay on with rain falling on it or do I then need to put plastic over to protect the tape?
Does double bagging help? Can I travel with a faraday bag inside a faraday box or does it affect something?
On the garbage can test, if you also put the foil tape on the inside of the handle area, there are probably holes in the can for rivets or something.
If you want to double bag do you need to have the first bag covered with something like a paper bag to insulate it from the second or just double bag one inside the other ? Thank you so much for your videos , that are very helpful to understand shielding.
Hi Larry, these bags are actually already insulated on their outer layer. The metal is sputtered in between the plastic layers.
Thank you for your quick answer. You have helped so many understand what to do to protect their electronics. Please keep it up. @@disasterprepper
Quick question.. does the gauge of steel effect this much. I'm going to use this steel drum that is much heavier than the trash can. If sealed properly..will the heavier steel help?
I understand the concern for grid damage from a CME. However, an EMP from a Neutron bomb would be the precursor to a far worse problem than a burned out generator. Personally I would want to be at ground zero.
You see in the movies they use a chip bag to block signals. Can you do a test with a chip bag...the foil type bag?
The cage covered by dri-shield bag material...to give more room to breath to the tera disk and have time to cool off a bit..
I have access to metal grease drums.
Much thicker than a trash can. I would think they would be very good as a cage against an emp. Of course sealed with tape.
Why is the garbage can on a chair? Does it need to be insulated from the concrete floor?
Thank you for making this video. My question is how much shielding is necessary to protect the electronics that I would put in a container? 50 db? 75 db? 100? or more? your creating a electronic signal an blocking it but your signal isnt really comparable to say a small to medium size emp, or is it? thank you.
Hi Patrick, if you run the numbers, most folks conclude that 50 dB is adequate to protect from an EMP. That reduces the field by 99.7%. Some would point out that if you look at MIL-STD-188-125, you'll find an 80 dB requirement (99.99% reduction). Folks can make their own decision, but in my assessment nearly anything would survive with 50 dB of shielding. As for my testing, I'm not determining survivability to an EMP, but rather shielding effectiveness. I sweep through the frequency spectrum of an EMP to determine the shielding effectiveness, which is standard practice. If a configuration can give 50+ dB across all frequencies, it will give 50+ dB reduction of an EMP. The difference in maximum field levels of a small, medium, or "super" EMP is only a handful of dB, so it doesn't really change the shielding requirements.
@@disasterprepper Thank you for the reply an the info I asked. I'll be doing some shopping at your web store.
It always stays a chance game depending on how close the EMP impact will be. Even a lousy shielding may protect your data e.g. at 70km distance of a nuke that else would erase them in 100km distance.
I am wondering if you suggest putting the equipment into the emp bag and then into the sealed garbage can, or if the bag alone is sufficient protection. I purchased several bags from your site today and would like to know if I should put them in garbage cans, too. Thank you so much for your invaluable information.
Hi Monica, first thanks for your purchase. As far as the bags, they provide about 99.7% reduction in electric field, which is enough to protect nearly any electronics. Some people either double bag or use a Faraday cage (trash can) for a second layer of protection, but it's really not necessary.
My cans are lined with wood and the lids are screwed and duct taped on. The cans are grounded and items in the cab are shielded by Dri Shield bags. Things like SW receivers and charge controllers. A full gamut of auto fuses and circuit breakers. Of course extra Walkie talkies
Dr., if I sent you some material, could you test it? Smallest workable dimensions for a box to be tested would be best as I don't have a ton of it. Also can you tell me what material(s) will block 5 G?
When I do the testing, the container has to be large enough to hold my spectrum analyzer. See my video of the large ammo can, which is about the size I would need to test something. I don't normally test other people's materials because, as you can imagine, it would be an endless job. I have a few times as special consulting activities, but I charge for my time. As for what would block 5 GHz, any conductor would as long as it doesn't have any seams or holes that approach a half of a mm in size.
Would it help to put an earth ground on the trash can?
Working on the trash can idea for my spare cb radio equipment. Hope it's enough to seal the can and then hide it in basement.
When properly sealed, the trash cans provide excellent shielding. You can either tape around the lid with conductive tape (cheap but a bit of a hassle to get in/out) or use a conductive gasket around the sidewall of the lid (more expensive but convenient).
I am mostly concerned about family data..docs..pictures, videos, stored in few teradisk which are constantly running.. i guess if i were to sealed them in a dri-shield bag they would overheat as the bags are small. Could i get enough protection from a cage made with copper mash which then i could cover with the material of the dri-shield bags properly sealed of course..
Would this help with a CME? Furthermore, after such an event, I'd want to open my can and use a radio etc. How would I know when it safe to do so?
A CME would affect satellites, radio communications, and the power grid (as well as things attached to it), but it wouldn't damage small free-standing electronics.
Would grounding of the can (or even the bags) make a difference of improving the shielding?
No. It's a misunderstanding that grounding would improve the RF shielding effectiveness of the Faraday cage.
Do you have any test data for using a Dri Shield 3400 bag inside of a sealed aluminum trash can? I purchased your book but it does not address the layered effect. Should someone line the can with non conductive layer cardboard, carpet padding etc?
I have tested the two combined, but it is greater than my test equipment can measure. Typically, you can assume the protections roughly add (i.e., 50 dB + 40 dB = 90 dB).
Would it help to ground the trash can?
So how about putting the items in an EMP bag and then seal them in the can?
Never mind, I saw the reply to an earlier question. Good stuff.
I would to know how much emf can pass through a seam between a painted steel surface and aluminum foil taped to the surface with a few bits of gaffers or regular duct tape. I have my guns in a Fort Know safe made of 10 gauge steel. I then cover the EMP resistant Sargent & Greenleaf digital electronic lock with a stainless steel bowl, which I then cover over with aluminum foil. The aluminum foil extends about 3-4 inches beyond the border of the lock and is taped down using regular duct or gaffers tape. This arrangement makes it relatively easy to gain access and should offer some level of additional protection to the lock so that in case of an EMP I won't be locked out of my safe. Judging from this video it appears the trash can allows considerable EMF to pass through the small gap around the lid. This would be valuable to know for the many gun owners that worry about this issue.
Awesome, thank you!
Love this stuff
Can you get these testing items at the Dollar store? LOL, just a tad expensive and technical for the average Joe... is this a home-made anechoic chamber your in?
I agree, the equipment is expensive. The chamber is a Lindgren shield room, not quite an anechoic chamber, but quite good at shielding RF.
Do u think it possible to make faraday cage out of your room with a door?
Yes, it's possible by lining the walls, floor, door, and ceiling with aluminum foil. It takes some work though, and you have to pay special attention around the door. I have a photo of a room I created this way in my EMP preparedness book.
I lined my garbage can with some carpet padding. Is there any problem with this or should I have just used cardboard? I realize there is no emp benefit but I wanted a nice lining to keep stuff secure.
That should be fine.
Would grounding the can help? Is that required for EMP Protection?
No. It's asked quite often, but grounding a Faraday cage doesn't help the shielding effectiveness. Grounding becomes important for shielding in other applications but not with Faraday cages.
I haven't seen all your video's yet but does perforated metal work better then aluminum screen? The holes in the perforated metal are 3/32 of an inch which is smaller then the holes in a microwave. Also in making a faraday cage, if you use both materials can you just sandwich them together are do they have to be separated with separate earth grounds?
I haven't tested perforated metal or aluminum screen, so I can't comment on which would be better. The hole size (longest diagonal distance) has a strong effect on the shielding effectiveness, but so does how well the weave of metal interconnects. If you make a multi-layer Faraday cage, you'd want an insulating layer (air is fine) in between them. In general, Faraday cages do not need to be grounded, although it likely wouldn't hurt the shielding either.
ohhhhhh that sucks....puting a layer between them makes the build a lot harder, especially the door, lol. Thanks for the advice.
If you were to use the EMP bags on your website and put them inside of the trash can sealed with tape would the effect be even better shielding or is it ineffective?
Yes, layering like this is even more effective. It almost adds... so if the bags provide 50 dB of protection, and the can provides 40 dB, you might get close to 90 dB when using both.
Thank you for clarifying. I will be buying the bags on your site on my next payday. I kind of thought it would be more protection but I'm really happy to see that it almost doubles. Thank you for your time and videos.
@disasterprepper
I have a question.
Could you try to protect a SSD in such a metal container, put some Data on it, making sha256 checksums of the data and then try to destroy the SSD with an EMP?
I would be interested to see, if a such protected SSD might survive that.
Creating an actual EMP is very difficult. It requires a full EMP simulator, which I don't have. I test at lower levels and measure the effective shielding.
disasterprepper
I understand. Thank you for your answer.
Dr. Would using those bags and putting them inside a sealed garbage can be the best way to protect electronics from emps/solar flares ?
There's no need to use a Faraday cage for solar events, only for EMPs. Solar events have much lower frequency content that doesn't couple well into small-scale electronics. The big concern for solar events is damage to things connected to long conductors (such as the electrical grid). But yes, for an EMP, putting items in these EMP bags does a good job of protecting them. You can double up by then putting those bags into a metal trash can if you like. It will provide additional shielding. My assessment, however, is that good quality bags would almost certainly be enough by themselves.
Would lining the inside of the trashcan with silicone or putting items inside a silicone bucket inside the trashcan make any difference?
You can line the can with an insulative material. It can make it easier to store items inside, although it may not be required (depending on what you store). The insulating material won't affect shielding, but it can keep anything metal on the electronic items from touching the inside of the can.
Hi Doc... very much enjoyed the video, really informative and comprehensive, nice work.
Here's a question for you, or anyone else out there who might know.
I have a 40' shipping container which I use as a garage for my 4x4. Would the container behave as a Faraday cage in the event of an emp and, as it is resting directly on 8 concrete plinths, would it be sensible to earth it with copper pipe, or earthing cable ?
Would be great to have a heads-up on it.
Best regards.
It's on my to do list to test a shipping container. My guess is that it would do a decent job of shielding items, perhaps 20-30 dB of protection. The obvious leakage points would be around the doors and along any unsealed seams. Once I test a container, I'll be sure to post my findings.
Hi again, Doc... that's great, thanks for the swift reply. Problems with leakage around the door seals makes sense. As for a future video, if you do run a test on containers it'd be superb. As you know, there are so many folks now using them for storage that it would be really reassuring to have some form of definitive evidence of just how safe they'd be in the event of a pulse. Also, if you do have any thoughts on how to remedy the door-seal problem, that would be 100% good news. Anyway, thanks again for the reply. Stay safe, and best wishes to you. Regards, cuhurun.
Yes, when I look at the container's effectiveness, I'll try out a few things to see how it can be improved by better sealing the container.
Excellent news, Doc. I look forward to eventually catching up with your findings. Cheers !
Dr. Bradley,
It's a very informative video and well done experiment! It's great to have this resource as there is quite a bit of speculation online about EMP shielding. I very much appreciate that you have actual lab equipment and follow rigorous methods to give us this high quality information.
A question I have is regarding the use of metal trashcans (or any metal container) with some kind of gasket to avoid having to un-tape and re-tape when opening/closing the can/container. You allude to the use of gaskets in the video. What materials can be used for that?
One thing I don't understand completely, which might help in being creative with a solution, is the physics of the trashcan rim "leak". Do you cover this in any of your source materials?
Do you hypothesize that if the can lid were forced shut tighter causing more metal to touch, for example with some kind of lever or screw type clamping mechanism, this would improve the shielding characteristics?
Thanks!
Hi Ken, all good questions. The thin seam (even partial seam) around the lid can leak significant energy. That's why we tape it with conductive tape. You could use a metal gasketing material (search EMI gasket). You could even make your own out of something conductive. Some folks use EMP bags (see disasterpreparer.com/emp-bags) inside the can, and leave the can untaped.
Is that room EMP proof? That's one heck of a door lock.
The shield room has 110 dB of shielding, so yes, I'd say definitely EMP proof.
Do you have a video explain the room build?
It's a standard shield room by ETS Lindgren. They put them up for RF test companies. You can also buy more ad hoc structures, such as RF tents, that work well.
4:20 Copper tape is for contact. If contact isn't needed, aluminum tape is sufficient.
Thanks for this great video!
I have a question, what if you put your gear inside a 3400 bag, and then inside a non conductive box and then put that box inside an other 3400 bag?
Would that not be better since the to shields don't touch or conduct each others EMP?
The bags are insulative on the surface, so they do fine stacked directly.
Okay great, thanks!
Would it give a significant better protection to have two 3400 bags stacked? Am looking for 100-120 dB protection for some ESD and RF sensitive gear.
Thank you!
How much db reduction is sufficient?
How well does the trash can work if electronic items are placed inside sealed EMP bags then placed inside a grounded metal trash can sealed with foil? Thanks
Layering like this can easily provide 80-90 dB of protection. It's the preferred method of getting very high shielding levels.
Hi Doc can you show what the best way to build a Faraday cage for a bed? Also could one hook up a grounding sheet while being in a Faraday Cage sleeping?
If you're looking for a way to block high-frequency RF energy, you could hang a canopy over the bed using sheer conductive cloth. It sort of looks like mosquito netting. Likewise, if you're worried about energy coming up from underneath you, you could put a layer of conductive cloth under the mattress. I know one lady who did this and said that it helped her quite a bit.
10-4 and thank you for the information
Sleeping always in a zero field of a faraday cage is unhealthy because the body needs the natural DC electric field.
I have only the side to the neighbouring wall next to the bed shielded (overleaping aluminium strips) and have a metallized roller blind against the mobile radio mast.
What about the thickness of the shielding material? I've read up about the Skin effect, could a higher powered pulse like an EMP instead of your test rig be able to bleed through the conductor due to skin effect? (Atleast for the lower frequencies like
Skin effect is the term used to describe the tendency for high frequency signals to "crowd" to the surface of conductors. And yes, at very low frequencies, the formulas yield large skin depth values. That said, it's really not relevant for low frequency radiated wave energy (i.e., 100 kHz) because the wavelength of such signals is so long that the energy won't couple well into the conductive surfaces of a small object (like a trash can or EMP bag). Consider that the wavelength of a 100 kHz signal is roughly 3,000 meters. That means that it would need a conductor perhaps 300 meters long to couple into without significant loss.
Another question not related to faraday cages if you don't mind. I've heard so many conflicting opinions about standard solar panels and whether they are vulnerable to emp damage or not. Could you share you opinion on this?
No one knows for certain, but the best analysis seems to suggest that the panels themselves would likely survive, but the controllers and diodes would be prone to damage.
FYI: I'VE WRAPPED UP "SMART METERS" WITH THAT HEAVY GUAGE, "ALUMINUM DUCT TAPE", AND I THINK IT "DUMBED THEM DOWN" A TAD!... LOL!!!
With the can, would it make a difference if it were grounded - a line direct to a ground rod?
No, we tested many times, and ground the cans made no difference in shielding. The reason is that we're not in the near field of the source (that's technical jargon for grounding doesn't really matter in this case).
Here's my name on this comment. I like and appreciate you and your work. You're my Go-too EMP person.
I ordered one of you EMP sensors a few weeks ago.
HOW ARE THEY COMING AS FAR AS BEING READY TO SHIP?
Hi Ken, we are still on track for getting these in the month of May.
Hi there, you mention the 3400 line of dri shield bags, I noticed there is a 3700 line as well.
Would I be able to rightfully assume the 3700 is 1 step above the 3400? Any answer would be greatly appreciated!
No, not necessarily. The bags vary in material, durability, translucentness, etc. Of the ones I tried (about a dozen types), I like the Dri-Shield 3400 the best. All of the Dri-shield bags did well except for the 2700, which is very slippery and hard to seal well.
Right on, appreciate the reply!
What is your assessment of smartmeters? Should a smartmeter protection cage be grounded or not?
I would think that the smart meter is in the near field of the offending signal, and would therefore, normally be grounded. When in the near field, grounding helps to provide a conductive surface on which to terminate the electric field lines.
Thanks
Something I've wondered for a while - would a heavy gauge steel "job tool box" provide any shielding if *not* taped? (assuming it was grounded and the electronic devices inside are isolated via non-conductive containers...) It is not practical for me to store most of my electronics in a sealed (tapped) trashcan as most of them I would desire to store for an emergency I also regularly use and cannot afford spares for to set aside. I'm hoping find something that could provide some degree of protection, possibly enhanced by being tucked away in the back corner of my underground basement, and might also provide some protection and also some degree of accessibility. Thank you for any thoughts on this.
Hi Calvin, lots of people have converted tool boxes and truck boxes to Faraday cages. But they usually install gaskets around the inside lid to make a tight RF seal. You have to pay attention to any seam to get good shielding.
My galvanized can has two vertical seams opposite one another on the body of the can. Should they be taped over, and if so, does it matter if they are taped on the inside or the outside. There are also perforations where the handles are fastened and where the lid handle is fastened. Are these small perforations of consequence. Thanks in advance for any info.
The seams on mine are folded metal, so there was no appreciable leakage. If you're worried about yours, you could certainly run a wide strip of conductive tape. It doesn't matter if on the inside or out. As for the small holes around the handle, they won't leak enough RF energy to bother with.
@@disasterprepper Thank you so much for the answers.
Instead of a spectrum analyzer could you use two way radios, or even 5GHz or 2.4GHz Wi-Fi networks, and see if a connection can still be established?. Of course the Wi-Fi router would have its own power source.
You can, but you wouldn't know the exact signal level or shielding effectiveness.
Great video sir. Very informative. What about Faraday Defense bags or Blackout Faraday Shield bags?
Not sure about those products. I'm assuming they are specific brands. Some brands are very good. Others built around hype. Can't say about those.
Can you do some experiments with and without grounding, using for example an eight foot ground and an rf ground, etc. Timothy, N7HLS
Hi Tim, if I get a chance, I will show how grounding affects the overall shielding. It won't actually make any measurable difference for a Faraday cage. It would, of course, be critically important if we were trying to shunt away energy, such as with a lightning strike.
where do you get the mesh gasket?