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[Ham-80211] Amateur Radio and Emergency Communications

nz8r at att.net nz8r at att.net
Wed Jun 22 23:37:59 UTC 2005


Guys,

Maybe I'm being simple minded, but I've survived direct lightning hits on one part of my tower, while not taking out other equipment, including 802.11 equipment with outside antennas.  Metal thats grounded with appropriate lightning protection won't protect us?  My surge and lightning protection came from EDCO (the guys that do data centers).  For my hardline they asked how much power I was running so that the clamping products were sized for the power levels.  Just a thought.

--
NZ8R on the air
N9477V in the air
40'23.106", 82'56.643" ICBM

			
			

 -------------- Original message ----------------------
From: Chuck Mayfield <charleslmayfield at comcast.net>
> At 06:12 PM 6/22/2005, you wrote:
> 
> >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
> 
> Hi Dave,
> A router inside a metal ammo can would be most likely protected from EMP 
> provided it was not connected to exteral systems that provided "antennae" 
> longer than about 30 inches, based on what I have read.   I suggest that 
> amateur radio operators store ALL their spare equipment in Faraday Cages 
> (look it up on the internet).  I don't expect you to have anything to hook 
> your 802 equipment to in the event of an EMP attack.   And, yes it in 
> certainly conceivable that a state sponsored terrorist organization could 
> accomplish such an attack.
> 
> Chuck,
> AA5J
> Plano, Texas
> 
> 
> 
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> 
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