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[Ham-80211] Amateur Radio and Emergency Communications

David Young dyoung at pobox.com
Wed Jun 22 23:12:46 UTC 2005


On Wed, Jun 22, 2005 at 05:41:46PM -0500, Chuck Mayfield wrote:
> 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 EMP  at an altitude sufficient to blanket 
> the North American continent.  After such an event, all solid state 
> electronic devices would probably be completely useless, since th EMP would 
> destroy a significant percentage of the semiconducter junctions included in 
> their design.  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.  Amateur operators 
> that plan to supply emergency communications after such an event must 
> either have stockpiled and kept operational tube type equipment and or 
> protected selected semiconductor base equipment by housing it in a Faraday 
> shield for protection against EMP.
> 
> How much of what we are discussing meets these criteria?
> 
> 
> Think about it people!  In my considered opinion, the most likely terrorist 
> threat we face that could cause such a scenario is not unlikely.  All the 
> terrorists (or any other enemy for that matter) needs is a nuclear device 
> and a launch vehicle capable of sending a device about 100 km over 
> mid-North America and detonating it.  The launch site could be anywhere 
> outside (or possibly inside) the territorial boundaries of North American 
> countries.

Chuck,

It seems unlikely that a terrorist organization could make such an
attack twice or more, since rockets and nuclear bombs are expensive.
802.11 equipment is inexpensive, and computers keep getting more and
more cheap.  Suppose radio operators make it part of their plan &
budget to store two (or more) instances of all vulnerable equipment
(in Faraday cages?) for rapid re-deployment?

Twice I have built wireless routers inside of ammo cans.  I figure these
would be Faraday cages, if it wasn't for the antenna & ethernet ports.
Do you think lightning arrestors on ethernet & antenna jacks ports be
effective against EMP?

Dave

-- 
David Young             OJC Technologies
dyoung at ojctech.com      Urbana, IL * (217) 278-3933




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