Radiation Issues In Nuclear Blasts- Part 2, by Dr. Bones of doomandbloom.net

World War III

This is the second part of this article on radiation issues in nuclear blasts. We’ve defined radiation and various types of bombs as well as radiation’s effects on living things. Today, we’ll look at what we can do to prepare for radiation exposure, treat its effects, and more.

Radiation Sickness

The medical effects of exposure are collectively known as “radiation sickness” or “Acute Radiation Syndrome”. A certain amount of radiation exposure is tolerable over time, but your goal should be to shelter your group as much as possible.

Terms For Measuring Quantities of Radiation

To accomplish this goal, we should first clarify what the different terms for measuring the quantities of radiation mean. Scientists use terms such as RADS, REMS, SIEVERTS, GRAYS, BECQUERELS, or CURIES to describe radiation amounts. Different terms are used when describing the amount of radiation being given off by a source, the … Continue reading

Radiation Issues In Nuclear Blasts- Part 1, by Dr. Bones of doomandbloom.net

World War III

Although many don’t view a nuclear event as a likely disaster scenario, it’s important to learn about all the possible issues that may impact your family in uncertain times. Given the instability in the Korean Peninsula and elsewhere, the issue of nuclear blasts and the radiation they emit is a timely subject.

Understanding the Definition of Radiation

The quick definition of radiation is energy given off by unstable matter in the form of rays or high-speed particles. The following is some basic chemistry paraphrased from the U.S. Nuclear Regulatory Commission (US NRC): All matter, including you, is composed of atoms. Atoms are made up of various parts; the central nucleus contains minute particles called protons and neutrons, and the atom’s outer shell contains other particles called electrons. The nucleus has a positive electrical charge, while the electrons have a negative electrical charge. Neutrons are, well, neutral. These entities work within … Continue reading

Letter Re: Metal Building as a Faraday Cage

Metal Building as a Faraday Cage


I will be building a small building to house electronic equipment (batteries for off-grid) and want to protect it from any EMP type of conditions. If we use metal roofing and clad the outside in corrugated metal would that be satisfactory protection? There will have to be ventilation for it too. The equipment will have to be well grounded.

HJL’s Comment:

If the panels are bonded together well (meaning more than just the 1 screw every 4 feet) and you have some form of conductive flooring also bonded to the building, then yes, it would work. Most metal building will not work well because of those two deficiencies.

Letter: EMP Foil Wrap

EMP Foil Wrap

Good morning, Hugh and James,

I’ve posed questions before RE: EMP protection, and now I have one or two more.

Survival blog had a recent series of posts about how to EMP-proof steel ammo cans; I found them enlightening. but they sparked some questions.

A Faraday Cage

The purpose of a Faraday cage is to completely enclose the item one wishes to protect with a conductive material. This will not permit passage of electromagnetic energy of certain wavelengths. The usual approach to Faraday cages is to exclude all wavelengths of electromagnetic energy. Different electronic components may also be susceptible to energy of different wavelengths. An EMP event may include myriad wavelengths of electromagnetic energy. This creates the preference for solid material, rather than mesh, EMP protection.

Protecting Electronics in Metal Military Surplus Ammunition Cans- Part 3, by J.T.

Faraday cage gasket

I am sharing a better solution for protecting sensitive electronics stored in metal military surplus ammunition cans made into a Faraday cage. In the Part 1, I talked about the ammunition cans that can be used and began the instructions for building ammunition can gaskets by listing the materials and tools required. Part 2 of this series consisted of the bulk of the instructions of how to make and assemble the RF and EMP shielding gasket, and we are continuing with these today, in Part 3. The following instructions are for a 20mm M548 ammunition can.

16. If you want to “belt-n-suspender” the conductivity between the sheet metal gasket and the lid, then remove some of the paint to reveal bare metal so that you have a good bare metal contact between the sheet metal gasket and the lid.

The sheet metal gasket with the copper mesh tape will be … Continue reading

Protecting Electronics in Metal Military Surplus Ammunition Cans- Part 2, by J.T.

Lid Gasket

I am sharing a better solution for protecting sensitive electronics stored in metal military surplus ammunition cans made into a Faraday cage. In the Part 1, I talked about the ammunition cans that can be used. We then began the instructions for building ammunition can gaskets by listing the materials and tools required. Now, let’s move on.

Making and Assembling the RF and EMP Shielding Gasket

The following instructions are for a 20mm M548 ammunition can, which is my preferred can size. If using another ammunition can, you will need to make adjustments in measurements within these directions to adjust for your ammo can’s size. I’ll give some guidance along the way for doing so.

1. Cut the sheet metal into a 7” by 16¾” rectangle, for the 20mm can.

But always start out by taking a good measurement. You know the old saying of “measure twice, cut once” still … Continue reading

Protecting Electronics in Metal Military Surplus Ammunition Cans- Part 1, by J.T.


In this multi-part article, I am sharing a better solution for protecting sensitive electronics stored in metal military surplus ammunition cans. There are many references for making a Faraday Cage on SurvivalBlog. Some references go back as far as 2005. One solution was proposed in 2006 that required the removal of the rubber gasket on ammo cans and replacing the seals with a conductive material (stainless steel or steel wool). Other articles suggested the use of a galvanized garbage can that is sealed up with conductive metallic tape, or an open head steel drum, or using an old microwave oven and a metal cabinet. I have read and researched many great comments and feedback on the effectiveness of these EMP protection measures.

Previous Proposals

All of the proposed solutions are more or less effective. … Continue reading

Letter Re: Does EMP Affect Solar Panel Systems?

EMP Solar panel

EMP Solar Panel

Good day sir. The talk of EMP has greatly increased recently for many reasons you are well aware of. What would happen to either grid tied or non grid tied solar systems in this instance? What would happen to generators as well? – R.C.

HJL’s Comment:

Two of our Writing Contest sponsors, Portable Solar LLC and Quantum Harvest, LLC, both specialize in EMP hardened systems. You should check their sites out and also the videos that they have on YouTube. We have several other advertisers that sell Solar equipment and it would be worth your time to check with them as well, though they don’t specifically advertise EMP hardened systems. Generators are more robust (except perhaps for the modern inverter units), but if they are grid tied they are … Continue reading

Letter Re: EMP Protection Measures

Steel drums

Hugh and James:

I’m missing something regarding EMP protection measures, and I could use some help.

I have researched EMP, how it’s created, and the common frequencies of EMP. I’ve looked into its relative intensity based on creation mode, altitude (in the case of nuclear devices), and the extended effects attributed to conductive networks. I understand what a Faraday cage is and how it works. And I’ve read numerous articles, lots of forum comments, endless opinions, a quantity of engineering documents, and several much learned evaluations on protecting against EMP.

The Problem

So here’s where I keep running aground: Protecting from EMP is, at its base, a simple affair. You provide a conductive shell around what one wishes to protect. Grounding that shell, or not grounding, is a subject of debate. However, my experience with electronics indicates that if the shell is doing its job, grounding it is not a … Continue reading

Letter: Faraday Cage Question

Faraday Cage

Good afternoon!

I have a question on adapting a homemade Faraday cage. I am getting a little paranoid about these two North Korean satellites in orbit over our country.

Would a metal mailbox, such as can find at the local hardware store, be acceptable protection? I am trying to put together something simple for really, really cheap! It has a larger size and is easier to obtain. It is also cheaper than some of the other options I have been reading about on constructing a Faraday cage.  T.B.

HJL’s Comment:

Most any metal container will work as a Faraday cage with a few simple preparations. The metal needs to have a good electrical connection between the various parts. If you are using painted metal, you will have to remove the paint where the electrical connection needs to exist. Galvanized metal works really well. If a metal mail box is not large enough, you can consider a 30 gal trash can with a metal lid…. Continue reading

Letter: Advice for Disabled Suburban Retiree Preppers

HJL and JWR,
I’m seeking links or tips on how a 77-year-old disabled person can defend his property in case there’s TEOTWAWKI. My wife is 72.

We live in a middle class subdivision 45 miles from Cleveland, Ohio. Because of physical disabilities (neuropathy, bad knees and legs) I am not very mobile.
I use walker/cane most of the time.

We are moderately prepared (food, guns, ammo, junk silver, etc. A retired Marine lives at the other end of the block but says he will bug out if SHTF.
Nobody else on the block seems even to be aware of the dangers of a potential disaster (natural or man-made).We are one block from main artery, one mile from an interstate.

Finally, where is the best place to shop for potassium iodide?

Thank you for what you do on the blog.  We have been … Continue reading

Letter: Using Military Ammo Cans for Faraday Shielding

Dear JWR:
The use of military surplus ammo boxes as Faraday shields was recently mentioned again in SurvivalBlog.  But readers should be reminded that these cans will not work in the configuration where they are normally purchased.  This is because the boxes have a rubber gasket to seal the lid from water and that makes the lid not in [electrical] contact with the body of the can, thereby losing the [EMP] shield effect.  Regards, – Dave X.

JWR Replies:  You are correct.  As mentioned previously in SurvivalBlog, the best approach is to remove the rubber gasket,  rough up the metal on both the top edge of the can lip and in the gasket groove (with sandpaper, a wire brush wheel, or a Dremel tool rotary stone) and replace the thickness of the gasket with stainless steel wool which is tacked in place with small globs of epoxy … Continue reading

Letter Re: EMP Telltale


Whenever the power goes out wherever I am, the first thing I do is see if my battery-operated watch is still working. I suspect one of these times, the screen will be blank or just chaos. – Sid, too near Niagara Falls

HJL Comments: As technology advances, the gate sizes grow smaller making such electronics more susceptible, but at the same time manufacturers recognize that they are more susceptible to static electricity as well. As a result, manufacturers almost always include some basic protection in the on-board circuits. Add to that the concept that the amount of energy absorbed by these electronics is directly related to the amount of “antenna” on the circuit board and you end up with practically no idea whether your watch will survive or not. The circuits are so small that the antenna lengths are negligible (unless you happen to be plugged in charging the … Continue reading

Letter Re: Using EMP-Hardened HF Ham Radio


I strongly recommend against using any Heathkit rig for an emergency radio. There was one solid state Heathkit but it was a rebadged, factory assembled Yaesu. All others were built by an individual, whose attention to detail you most likely have no idea about. They are known in the hobby as “GRIEF kits” for a GOOD reason. They fail – early, and often. They have too many disadvantages for the emergency backup purpose. Besides all the ones mentioned by the original author:

  • They have high (LETHAL) voltages inside.
  • They require 120V AC power.
  • They have no cooling fan on radio, nor power supply, and these digital modes are 100% duty cycle on transmit.
  • They have no easy way to “turn down the output power”, and hence avoid detection (OPSEC), and save precious (AC) power.
  • They are old, and WILL fail. (Did I mention that before?). Tubes are fragile, … Continue reading

Using EMP-Hardened HF Ham Radio to Send/Receive E-Mail During Nationwide Outage- Part 1, by PrepperDoc

There are multiple possible scenarios that may result in a regional an/or national combined loss of Internet connectivity and cell/telephone service, during which you would probably wish to maintain communications to loved ones and others. EMP may destroy routers, cell towers, and power sources; solar coronal mass ejection (CME) may remove power from all communications systems; cyber warfare may have similar outcomes. Travel in some of these circumstances will be difficult, or dangerous to impossible.

Ham radio VHF/UHF repeaters may go down, due to power outages or EMP. Direct, point to point simplex VHF Ham radio will still work (even after an EMP, if hand-held radios were at all hardened or protected) over modest distances. Long range HF direct Ham radio communications will work (possibly after a delay of any EMP), presuming you had protection (if EMP) and have your own power. However, they will be of less usefulness … Continue reading