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[Ham-80211] Amateur Radio and Emergency Communications

Perry - K4PWO k4pwo at comcast.net
Thu Jun 23 03:36:54 UTC 2005


You're not being simple minded... For a single device to "blanket" the 
continental US with a pulse strong enough to cause wide spread damage, it 
would need to be a very high yield device (remember field law)!  A "nuke" of 
that size would be extremely heavy requiring a heavy lift launch vehicle. 
Since it is highly unlikely that a group could construct such a weapon 
system under our noses, it would require an intercontinental ballistic 
missile to deliver it.  Overall, the likelihood of a "terrorist" group, 
state sponsored or otherwise, to have these resources is remote.

73 de Perry - K4PWO

----- Original Message ----- 
From: <nz8r at att.net>
To: "TAPR Mailing List for Ham Radio Use of 802.11" 
<ham-80211 at lists.tapr.org>; "TAPR Mailing List for Ham Radio Use of 802.11" 
<ham-80211 at lists.tapr.org>
Sent: Wednesday, June 22, 2005 6:37 PM
Subject: Re: [Ham-80211] Amateur Radio and Emergency Communications


> 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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