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[Ham-80211] Re: EMP

Timothy J. Salo salo at saloits.com
Tue Jul 19 22:50:23 UTC 2005

> Date: Tue, 19 Jul 2005 13:14:23 -0400
> From: "KC2MMi" 
> Subject: [Ham-80211] Re: EMP
> But if you find any hard facts on EMP, I'd be glad to hear them--in another
> more appropriate forum. They've got nothing to do with 802.11 equipment per
> se.

At the risk of confusing the issues with the facts, I composed, but never
sent, the following e-mail when this thread first started.

[And, I won't even try to have the last word by claiming that any response
is off-topic...]


> Date: Wed, 22 Jun 2005 17:41:46 -0500
> From: Chuck Mayfield 
> Subject: Re: [Ham-80211] Amateur Radio and Emergency Communications
> I have been monitoring several groups that seem to be pushing digital 
> communications via internet and radio for emergency communications.
> All discussions that I have seen neglect the possibility of electromagnetic 
> pulse (EMP) from a nuclear device...

I suppose this is something worth thinking about (outside of the normal
defense community)...

> Only ancient tube type equipment and maybe equipment 
> designed with radiation hardened semiconductor devices would survive.  A 
> majority of equipment designed / developed for DOD end-users has been 
> radiation hardened since about 1985.  Other than that, almost all 
> commercial electronics is subject to destruction by EMP.  ...

I am no expert in these matters, but I think you want to differentiate
between "protected from EMP" and "radiation hardened semiconductors".

The FAS provides a nice overview of EMP effects:


Note that the following is contained in this FAS report:

	"In principle, even a new nuclear proliferator could execute such
	a strike. In practice, however, it seems unlikely that such a state
	would use one of its scarce warheads to inflict damage which must be
	considered secondary to the primary effects of blast, shock, and
	thermal pulse. Furthermore, a HEMP attack must use a relatively large
	warhead to be effective (perhaps on the order of one mega-ton), and
	new proliferators are unlikely to be able to construct such a device,
	much less make it small enough to be lofted to high altitude by a
	ballistic missile or space launcher.  ...

The FAS was also kind enough to put a copy of " Engineering and Design -
Electromagnetic Pulse (EMP) and Tempest Protection for Facilities" online:


Googling for "EMP" and probably "TEMPEST" will return lots of interesting

If you are thinking about EMP, you probably ought to think about
high-power microwave (HPM) weapons.  I seem to recall some reports
(or, perhaps urban legends) that amateurs (presumably generic
amateurs, not amateur radio operators) had created HPM weapons that
were capable of disrupting consumer electronics (i.e., don't try
this at home, particularly if you have any near-by neighbors).
For a good time, google for "EMP Gun" and read:


On the other hand, some reports about US efforts to thwart improvised
explosive devices, IEDs or road side bombs, sound vaguely like they
might be something along the lines of HPM weapons.

I seem to recall that when I looked into this stuff a long time ago, 
that TEMPEST stuff was classified, but that people seemed to have
apparently figured most of it out anyway.  And, in the current climate
and under the current administration, I might be a bit careful about
appearing _too_ interested in this stuff, particularly depending on
your ethnic background.


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