EMP Protection

[caneman]

Maybe one of you electrical engineers can straighten me out on this.

I read at one time that you could protect something like a C/B or AM/FM or small ham radio by sandwich style packaging.

Radio on the inside - next a box - next a total wrapping of aluminum foil - next another cardboard box.

I'm guessing you'ld have to do that with any antenna also.

Is that correct? Am I missing anything? Would this work for FRS handhelds? etc.

Some communications gear even if it's ears only would be nice to have and things like c/b and FRS are cheap to stick on a shelf with extra protected batteries.

 

[IndianasFinest]

Not sure what good it would be to even have a cb or radio if an EMP blast hits. It's gonna knock out the entire infrasructure that would be broadcasting.

 

[rambone]

What you're talking about is called a Faraday Cage.

I think you have the right idea, except instead of foil, you are supposed to use copper mesh screen. Some sources recommend that you tie this cage to ground.

The aluminum foil is for lining the inside of your hat with.

Do a search for "faraday cage" and you will find plenty of info.

 

[inxs]

Best device (use it myself) that I've found is an old .50 ammo can. Faraday cages are nice but a true cage is more or less calibrated for the event and that would be difficult. The military has done a lot of research and it was mostly inconclusive due to the number of variables. Antenna are not really subject to pulse problems of this sort. EMP is not an easy subject and will not be resolved until one happens. A lot has to do with time / rate of change and electrical length of the subject. Take four years of study and you might begin to get the idea......

 

[6birds]

here's a good read my brother sent me a few months ago.

AusSurvivalist - EMP Protection

 

[Beau]

Maybe one of you electrical engineers can straighten me out on this.

I read at one time that you could protect something like a C/B or AM/FM or small ham radio by sandwich style packaging.

Radio on the inside - next a box - next a total wrapping of aluminum foil - next another cardboard box.

I'm guessing you'ld have to do that with any antenna also.

Is that correct? Am I missing anything? Would this work for FRS handhelds? etc.

Some communications gear even if it's ears only would be nice to have and things like c/b and FRS are cheap to stick on a shelf with extra protected batteries.

From what i have read this is an example of a poor man's Faraday Cage. I found a couple sites that show you how to make them. It is important to have the box grounded.

For antennas I've read that they need to be disconnected from the radio unit and grounded.

 

[caneman]

I guess I totally misunderstood. I thought if I had a successfully shielded C/B and my daughter had one also, that they would function to talk between the two of us as soon as the blast was over (hour - day - week), and anyone within normal transmission range could be reached too. FRS would only be a mile or two but better than walking. Maybe 7-12 miles for C/B. 2 Meter I have no idea.

 

[inxs]

You should be able to. There will probably be some interesting propagation for quite a while, but short distance should be doable, more so with FRS than longer wave. EMP decreases with the square of the distance, which wasn't said here before or in the link provided- which is pretty accurate otherwise.

 

[IndianasFinest]

I guess I totally misunderstood. I thought if I had a successfully shielded C/B and my daughter had one also, that they would function to talk between the two of us as soon as the blast was over (hour - day - week), and anyone within normal transmission range could be reached too. FRS would only be a mile or two but better than walking. Maybe 7-12 miles for C/B. 2 Meter I have no idea.

That may be a possibility. I was under the assumption you were hoping to contact say police,EMS or any one else not prepared for the blast. You know what they say about assuming....lol. The thing about EMP that is so scary is we just don't have any real idea what will be effected, and what won't. I don't know if you read the current sticky on EMP, but another member asked about a faraday cage. Microwave ovens will work as a shield from EMP, and can be purchased for next to nothing at yard sales.

 

[caneman]

I'm guilty of making assumptions too. Mine is that the police either haven't had the money or motivation or knowledgeable guidance to do something like EMP prevention. I've thought communication would basicly come down to citizen to citizen.

 

[csaws]

I know someone does EMP testing so who tested and proved the microwave will work? Or is it just theory? If theory what is the theory based on?

 

[Arm America]

Theory or reality, who knows?

Let me adjust my tin hat.

According to the U.S. Government, if the Midwest is hit by one EMP device
of larger size ($400.00) the entire U.S. electrical grid could be disabled
taking years to rebuild.

This would revert most of us to living the life of 200 years ago.

Still thinking of placing a few things in the microwave, I hope its big.

Most readily available garden seeds have been genetically engineered to
only grow one season, meaning you can't replant what you harvest.

I read last week where the IN DNR claims about 13-14 days of
wildlife available to Indiana residents if SHTF scenario.

This does "not" include cows, pigs, sheep or fish.

Medical treatment.......don't count on much.

Clean water, adjusting the thermostat up a couple of degree's, all gone.

How many people have access to wood to keep warm,
how many even have a fireplace to burn it in?
Burn a fire, expect someone for dinner.

According to U.S. Government reports, Iran is our biggest threat on
the use of EMP'S with North Korea being second.

Did I mention the U.S. Missile Defense System had a 10% budget cut this Summer?

Who would have thought what seemed like yesterday, that a few terrorists,
(some with expired visas) were capable of killing and destroying
so many innocent lives.
And yet, our borders are still not secure. (What's it going to take)

An EMP going off should be something to think about and worth reading up on.
Can we prepare for it?

Well, I've always respected and admired how the Amish live.

 

[versuchstier147]

I had always thought if the device was off, it'd be fine.

 

[inxs]

Some may be, some may not. The only hope in knowing would be to know all the parameters of the blast and the exact situation and technology of the object you are planning to protect. Thin film stuff will fare the worst, most likely and vacuum tubes will fare the best- rule of thumb might be the newer the less likely to survive....

Failing that, the next would be to try to construct some attenuated infinite baffles, note the plural. Rise time can wreak havoc.

 

[rambone]

I know someone does EMP testing so who tested and proved the microwave will work? Or is it just theory? If theory what is the theory based on?

A Microwave Oven contains a Faraday Cage. Just look through the window and you will see the copper screen that lines all 6 sides of the box. Same thing that people describe how to build with a shoe box and copper mesh.

As far as testing, I don't know of any.

 

[jeremy]

I know someone does EMP testing so who tested and proved the microwave will work? Or is it just theory? If theory what is the theory based on?

Here let me go out back and bang off another nuclear event...

 

[Beau]

Here let me go out back and bang off another nuclear event...

I wonder how many lists this single post just got you put on.... They are watching.....

 

[teknickle]

A Microwave Oven contains a Faraday Cage. Just look through the window and you will see the copper screen that lines all 6 sides of the box. Same thing that people describe how to build with a shoe box and copper mesh.

As far as testing, I don't know of any.

Well, to test it....just press START on your microwave.
For the same reason no harmful amount of radiation passes out, it should keep the outside radio waves from coming in (well, at least in the 2.4GHz range--which is where microwave operates at).

A coulomb cage also prevent damage.

Military DID do extensive testing for this under the Tempest project.
(not for destruction, but for security).

For small devices, you can use one of those lead-lined airline-safe film bags.

I know it seems strange to think that even a disconnected and powered-off device can be damaged, but YES IT CAN.
The strong RF waves actually induce a current through the conductor it passes along.
That is why you want the cage grounded.
I don't know if a ferrite-choke would help with cables that must exit your cage (it depends on wave frequency and amplitude)

Concrete also is a great barrier to waves. 3ft of concrete can even stop gamma radiation. (alpha particles can be blocked by piece of paper).

 

[CarmelHP]

"The Effects of Nuclear Weapons" (1977 edition, earlier editions do not have the EMP Chapter) Chapter 11 is a good EMP primer. It notes hybrid protection devices should be tailored to the application for devices connected to EMP collectors, for example, a band-pass filter to stretch the rise time, connected to a lightning arrester in order to allow the arrester sufficient time to respond. For small electronic items, an ammo can sounds like a perfect metal cage, but avoid corners and edges. The biggest EMP collectors are RF items (like antennas) and stretches of wire (e.g., power lines) and stretches of metal (e.g., piping). There was testing using simulators going on back in the '60's and '70's, but my guess is that very little is going on now.

 

[inxs]

For small electronic items, an ammo can sounds like a perfect metal cage, but avoid corners and edges.

Should note- avoid the corners of the ammo box on the outside, not the inside. Piping will not be a major problem due to corona suppression effect.

It notes hybrid protection devices should be tailored to the application for devices connected to EMP collectors, for example, a band-pass filter to stretch the rise time, connected to a lightning arrester in order to allow the arrester sufficient time to respond.

I believe this has been proven useless as MOV's are too slow and silicon avalanche too fragile....