Re: thread "Uses of G.I. Ammo Cans"




dazed and confuzzed wrote:

> If you don't need the EMP protection, use 5 gallon buckets with
> replaceable screw down lids which are as water and airtight as ammo
> cans. (the lids can be bought at many survival oriented websites). You
> can get used buckets cheap. They are vermin resistant (nearly as good as
> the steel ammo cans) The only issue with them is that they aren't as
> space efficient as ammo cans.

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..223 cases only offer around 90dB of isolation. Not very good
attenuation
if one is expecting to cope with a NEMP.

A friend works at a compliance test facility, a big multi Faraday cage.
We
have been testing various items to see how much protection they might
offer.

A couple of layers of aluminum foil, in a antistatic bag, inside a .223
can will
give better then 130dB of isolation.

We had a nasty line of Tstomrs come through last night and got to do
some
test with natures EMP gear. Lightning. NEMP has faster rise times and
may
have much higher voltage levels. But we don;t have access to any nukes,
so we make do with the wimply stuff.

Our test used a modified FM BCBN receiver, converted from FM to AM.
Tuned
to 100MHz. Most of the refferences we have been able to locate agree
that NEMP
will peak around that frequency. Inspite of the best shielding we could
get,
good cookie tin inside the faraday cage, we could still here lightning
crashes
from nearby strikes.

How much isolation do you need to insure protection from NEMP?
That depends on teh V/mtr that the event produces. And we have data
that
lists everything from 1V/M, no problem, to several KV/M, which, if
true, would
present a significant challenge.

Terry

.