"One Second After"

[3000k]

EMP's havent changed since the 50's and our electronics are much more susceptible to EMP waves because theyre built cheaper and arent encased in real metal anymore. Ive been told that an ammo can that is well grounded (Bolt a wire to the can and then ground it) and then insulated on the inside is a good faraday cage... Im actually about to make one to store a GPS and a few LED drop-ins and lights and batteries.

Would the GPS Still work? Shouldn't the satilites be affected too?

I think Ive heard on the history channel that large enough solar flares produce EMPs.

For those of you who Have EZ-Pass or something simular for the toll roads, will the metallic bag they give you to shield the transponder from the receivers also work to protect against EMPs?

 

[Alan B]

To make a quick flashlight faraday cage use copper water pipe and solder it closed on both ends. Make it longer than the contents and pack on end to keep the contents away from a marked "cut here" section.

Use a hacksaw to open it when needed.

 

[TorchBoy]

Use a hacksaw to open it when needed.

Not like in the old days when it was a simple "Break glass in case of emergency." :sigh:

 

[gsxrac]

That'll work, but don't ground it. It's got to be insulated from everything, even the ground.

You are correct! Larger faraday rooms should be grounded but smaller stuff doesn't need to.

Now, see... This is where confusion sets in for me. I've read several different thing, and they all contradict each other. Some say the faraday cage has to be grounded, others say that it has to be insulated from the ground!!!

What's correct?

I have done another hour of reading on EMP and I now understand why you dont* ground a smaller faraday cage. When an EMP hits the grounding wire is actually more likely to act as an antenna to attract the DC like waves coming from the pulse.

A Faraday cage depends on a continuous conductor completely surrounding the volume. Ground is not required.

The problem with a steel ammo can is that it is not continuous - the lid gasket insulates the lid.

The connection between the lid and the box must be conductive all-around. Examples of this are found in radio shielding compartments - fingerstock and plenty of screws.

I will actually be building an ammo can up tomorrow. The can I have has the steel flaps that overlap and go down and touch the can so I am going to sand down the inside of the steel flaps and the metal they contact with to complete the connection. Then Im going to spray rubber bed liner inside the can for an insulator. Then I am just going to repaint the outside flat black (Purely aesthetic)

Would the GPS Still work? Shouldn't the satilites be affected too?

I think Ive heard on the history channel that large enough solar flares produce EMPs.

For those of you who Have EZ-Pass or something simular for the toll roads, will the metallic bag they give you to shield the transponder from the receivers also work to protect against EMPs?

Solar flares do produce EMP's. I think I read that we haven't had a large scale one since the mid 1800's but we are due to have one any time now.

I'm really not going to rely on the GPS but it would be a very good resource after an EMP as long as it did still work since it is loaded with topo maps. Plus an EMP would likely only knock out a select few satellites and as far as I know you dont have to align with every one to get a signal but the more you have the more accurate your GPS will be. Don't quote me on that because I could be wrong.

 

[gsxrac]

Another thing that was brought up on a different forum about an EMP effect is safes with electronic locks and no mechanical backup. If an EMP hits you will likely need many of the items that you keep stored in your safe and may not be able to access (for the sake of keeping this thread alive I wont discuss large safe contents but use your imagination lol)

 

[joema]

In the book - "One Second After", the U.S. gets hit with an ElectroMagnetic Pulse (EMP) as a result of a nuclear detonation above the continental U.S. This EMP cripples almost all of the electronic circuitry in the U.S. This includes our power grid, communications equipment, GPS...What would happen to an LED torch...I'm in the early stages of planning how to survive such an event, whether man-made or solar induced.
...

There are no natural events that produce EMP of a degree which would damage an LED flashlight.

Whether an LED flashlight would be affected by a nuclear EMP strike is hard to state definitively. A high altitude nuclear detonation can impose 50,000 volts per meter to conductors on the ground.

However there are many variables: detonation altitude, yield, distance, conductor (antenna) length, degree of shielding, susceptibility of the electronics to damage, and type of EMP waveform (there are several).

Whether the LED flashlight has a plastic or metal body is probably a factor. Also whether it's a simple direct-drive flashlight, a regulated light, or a microprocessor-controlled light could make a difference.

The GPS satellite constellation is hardened against EMP -- it's a military system designed for a nuclear warfighting environment.

A nuclear EMP attack in general requires a fusion device (ie H-bomb) to obtain the correct weight-to-yield ratio for aerial delivery. Fusion bombs are much more sophisticated and beyond the ability of smaller powers.

Also no small power would waste one of their few devices on an EMP attack. The U.S. military is hardened against this. If launched by missile, the trajectory leaves a "return address" for the launch point, plus tips off the imminent attack (lose the element of surprise).

A major power would only use an EMP attack as a prelude to an immediate full-scale nuclear strike. It's unlikely missile delivery would be used, for reasons already stated. Rather they'd be concealed in orbital satellites and detonated above the target in coordination with an immediate follow-up full scale nuclear strike. Whether your flashlight works during the 20 minutes between the two events is probably not important.

 

[Jay R]

I also dont know why people are saying modern electronics would be unaffected :thinking:...

What we are saying is that a small electronic item such as an LED torch is not big enough to pick up enough charge to damage it.
Every case of EMP damage I have seen reported was on something connected to the national electricity grid or another long length of wire in some form.
Try this, imagine 5 million people scuffing their feet on a nylon carpet and then all touching a 30 mile long telegraph wire at the same time. The resultant surge may burn out components at the end of the wire. Now, scuff you feet down a nylon carpet and then touch your Fenix. Still works doesn't it.
There's a big difference between a microchip connected to a 3 inch tube and one connected to a 500 thousand mile long electricity network.
Sure, your TV will be bust, the phone won't work, you won't be able to get cash out the bank or buy food, but on the plus side, your Nintendo DS and Fenix will still work fine.

 

[Liteskr42]

Ok so what we are talking about here is nuclear war and a collapse of our massive electronic network. Whether it is a nuclear attack or an asteroid or who knows what else, the best thing is to go the KISS route. As was stated if EMP is your main worry then go incandescent for lighting,AA for the cells and stock up on them in Lithium form. If there was a complete collapse of our fragile society like that, there are so many things that will be huge obstacles for the inidividual a flashlight will only be a small part of it. Water,food and safety from others trying to survive will be the primary obstacles which will take up a majority of your time. Spend more time making sure you have a way to reliably make fire/make clean drinkable water/adequate food for minimum of 2 weeks to start/have a way to protect/provide for yourself ie. firearms,axes,knives.

I am also of the camp that an EMP disaster is moslty Sci Fi embellishment and if it did come on a national/global scale it would be from massive solar flares or something way beyond what people could muster. Also, what if there was a nuclear attack of that scale? You would have warheads going off miles above your head. The fallout of radiation would come after the EMP and you would become a human flashlight before your skin starts sloughing off to the bone . How would you find non radiated water to drink? Though the urge to be able to see in the dark and not be blind is one of mans most basic fears and needs I do believe it will be way down on your scale of importance. How will we deal with the psychological factors like not being able to locate a loved one like your son or daughter and still focusing on your survival? The details of it are mind boggling!!!

 

[Mark-60]

That was an interesting read. I just finished it about a week ago.

-Mark.

 

[Skibane]

What we are saying is that a small electronic item such as an LED torch is not big enough to pick up enough charge to damage it.

Precisely.

The EMP described in "One Second After" was produced by detonating a nuclear bomb at a very high altitude (dozens to hundreds of miles) above North America. This high-altitude EMP (or "HEMP") is the only kind of EMP that has wide-reaching effects. There are other ways of producing EMP (microwave bombs, charged capacitors, etc.), but they're all very short-range - and thus aren't of much concern to anyone who doesn't live next door to a high-value military or terrorism target where some exotic EMP bomb might be exploded. HEMP is the only kind of EMP that has a range of hundreds to thousands of miles, and thus is the only kind that is capable of directly affecting the vast majority of the American population:

EMP does its damage by inducing a very brief, high-voltage spike in electrical devices. This spike can be strong enough to burn out wiring, "punch through" the thin semiconductor layers in transistors, diodes and computer chips, or cause the software in computer-controlled devices to go haywire.

However, the strength of the electrical spike induced in any electrical device by a HEMP burst is dependent on the length and physical orientation of any conductors connected to the device. Long conductors (i.e., AC power lines, phone lines, big antennas, etc.) receive a significant amount of the EM pulse; short conductors do not. In a device which isn't connected to any long conductors, almost no electrical spike is generated due to EMP, and thus the device is unlikely to be damaged. Most small electronic devices (i.e., cell phones, portable radios, PDAs, laptop computers, digital wristwatches, flashlights, electronic combination locks on safes, red dot rifle sights, etc.) would fall into this category - The few inches (or fractions of an inch) of conductors present in these devices is simply too short to intercept any significant amount of the EM pulse, and thus no damaging voltage spike is generated within them.

Similarly, the short length of the wires present in most vehicles (automobiles, motorcycles, ATVs, etc.) also intercepts very little of the EM pulse - and thus, is unlikely to be damaged. Also, the wiring in most vehicles is partially shielded by the vehicle's metal body (thereby further reducing the strength of any voltage spike produced by the EMP), and all vehicle electrical systems are designed to deal with the high voltage spikes normally produced by the ignition system, motor brushes, relay and solenoid coils, etc. This combination of factors makes vehicles very resistant to HEMP.

Here's an excerpt from the Report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack, Chapter 6, Page 115:

The results demonstrated that even modern, computer-laden vehicles are unlikely to sustain any significant HEMP damage.

THINGS TO REMEMBER:

1. There are other types of EMP besides HEMP, but all of them are short-range. Consequently, HEMP is the only type that is a significant direct threat to most of the U.S. population - Unless you live next door to a high-value military or terrorism target, HEMP is probably the only kind of EMP that's capable of reaching you.

2. Most motor vehicles and portable electronic devices stand a good chance of being usable after a HEMP burst, even without taking any special precautions beforehand. However, electric power, telephone, cable TV and internet wiring is very vulnerable to HEMP damage (as are any appliances that happen to be connected to these wires when the pulse occurs). Consequently, there is no guarantee that you'll have utility power, telephone service, cable TV, cell phone or internet service for weeks, months (or even years) after a HEMP burst. Services that rely on these utilities (police, fire, ambulance, traffic signals, city water and sewer) may also be interrupted.

Additional Reading:
Federation of American Scientists: Nuclear Weapon EMP Effects
Glasstone's EMP Effects of Nuclear Weapons blog

 

[march.brown]

I worked for a great many years in the Electricity Supply Industry, in Substations where the Voltages were either 275,000 Volts or 400,000 Volts.

During switching operations and particularly the opening of isolators, there was a lot of energy (noise) released into the atmosphere ... It was enough to lift the "mute" on any communication radios in the area, both hand held or those mounted in vehicles.

All our sensitive communication and protection equipment was housed in securely earthed cubicles ... The radio systems were either microwave or VHF systems and if the cubicle was not securely earthed, there were problems with the VHF systems ... When the Isolators were opened on a 400kV system, a large (and noisy) arc was drawn till it was extinguished by the isolator gap being too large ... This RF noise would lift the mute on the VHF base station if the cubicle earth was defective ... If the cubicle was not earthed then the outer braiding of the aerial coax cable would be "floating" and would pick up the interference ... With the cubicle earth securely connected, there were no such problems ... Hence my reason for suggesting the earthed cabinet.

It would seem that we would also need to have a couple of ordinary Maglites just in case the "One Second After" ever does occur.
.

 

[eyeeatingfish]

Not all electrical things are garunteed to fail. On one discovery channel program they were talking about a EMP research facility and they had a machine that made EMPs. They drove a car through it activated to show it disabled the car. Funny thing was the electric windows worked just fine.
I think the explanation said that things with fine wires like computers and stuff cant withstand it, but basic systems like an on/off electric motor would still work.

 

[Hamilton Felix]

Not long ago, a co-worker drove his new VW Passant back east to visit family. Lighting struck a tree along the driveway where they were parked. The insurance company discussed it with the dealership, then they TOTALLED his new Passant. He came home in a new car. His mother's slightly older GM car had three processors replaced (engine management, transmission and climate control), but they were able to fix it.

 

[Jay R]

Yes, but the torch in the glovebox still worked right !