[Wolves] Chris : Midlands Today

[Steve Parkes]

On 14 Apr 2005, at 10:43, Kevanf1 wrote:
>>
Ah, now I understand :-)
Yes, I saw the article.  Very good too.  All
>
ahhh, now I understand, that Chris ;-)


> about the way local and national radio hams were able to communicate
> with survivors of the Boxing Day Tsunami.  They did an excellent job
> in directing the emergency services to where help was needed most.
>
> I remember reading years ago that the internet would survive a nuclear
> war.  It would act as a way of communication.

The bits that make the internet work are spread all over the place and 
it was designed to route past bits that didn't work so it would out 
survive you ;-)

> At the time I wondered
> why nobody had thought of the magnetic pulse and the devastation it
> would cause with electronics.

only within a certain range of the bombs.  One of the discussions that 
most scared the staff at the pub we used to meet at was our apotaliptic 
air burst distruption conversation ;-)  big chunks of the workings of 
the internet are deep underground and under the ocean and every packet 
is routed in a adhoc basis.  When you turn off your router the internet 
doesn't go away, it just sends packets a different way.  It's like the 
sound of one hand clapping.

> Now forgive me if I'm wrong, but
> wouldn't the same happen to ham radio?  Unless it was an old tube set?

a crystal you grow from any metalic salt and a bit of wire will pick up 
some radio frequencies ;-)

it's intergrated circuits that have problems with electro magnetic 
pulses since there are all (to differing standards) radio transmitters 
and recievers and can be burnt out by powerful radiation in frequencies 
they soak up.

Pretty much every bit of electronics has to be tested to make sure it 
isn't buggered by radio waves and doesn't emit too many radio waves to 
the extent you could probably microwave your laptop for a minute and 
then (after cooling) turn it on with minimal effect ;-)  try this with 
your own gear, not mine.  Your modern tv won't be messed up by the 
effects of a motorbike engine in the street (for some reason motorbikes 
cause shed loads of radio rf when cars don't, it could be the body of a 
car acts as a faraday cage?) but an old black and white tube set 
proabably will be effected.


In most cases electronics just go on the blink when subjected to high 
doses of radio frequency and return to normal after it's finished.


On the TV not too long back a computer (a 286 if memory serves me 
right) was subjected to masses of radio energy in a testing chamber up 
to millions of gauss (if I have my units right) while running and as it 
got to levels that would probably cause lots of sickness in people it 
turned off.  They turned down the juice and it rebooted with lost bios 
settings.  This was at energy levels that would cause small metal 
objects to leviate but the computer survived it.  I doubt it would for 
long and the hdd could have been buggered too but it just rebooted when 
they turned the juice down to a post screen indicating lost bios.  So 
electronics can take more abuse than is given credit these days.

It was a myth at if F16's where within so many miles of an airburst 
they would fall from the sky due to failiure of it's fly by wire system 
(it has no traditional control just electronic) but I doubt the US 
would have it's primary dog fighter knocked out of the sky by anything 
but a direct hit and I think the myths probably started to stop 
americans hoarding batteries in the 50's and 60's ;-)

I am sure re- and some of the more radio savvy people (pun intended) 
can help you a lot more on this but I am pretty sure the fecked up 
ionosphere and a nuke war would stop long range short wave for a while 
anyway, but given the circumstances shorter range communication would 
probably help more.

>
> -- 
> Take care.
> Kevan Farmer

sparkes