Re: Detecting IEDs...


"Randy Poe" <poespam-trap@xxxxxxxxx> wrote in message
news:1194115237.145849.268490@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Nov 2, 12:35 pm, "Tom Potter" <tdp1...@xxxxxxxxx> wrote:
"John C. Polasek" <jpola...@xxxxxxxxxx> wrote in
messagenews:jabmi3177512u36l2bg5vvdbkvct5258rv@xxxxxxxxxx

On Wed, 31 Oct 2007 22:27:39 +0800, "Tom Potter" <tdp1...@xxxxxxxxx>
wrote:

"Sam Wormley" <sworml...@xxxxxxxxx> wrote in message
news:y%SVi.162029$Xa3.144835@xxxxxxxxxxxx
Tom Potter wrote:
"Sam Wormley" <sworml...@xxxxxxxxx> wrote in message

http://www.qsl.net/n9zia/wireless/gps_jam-pics.html
o Operating Range - 150-200 km
o Output Power - 4 W

"THE GPS/GLONASS JAMMER HAS AN OUTPUT POWER OF 4 WATTS AND CAN
EFFECTIVELY DENY USE OF GPS IN AN AREA RANGING AS FAR AS 150-200
KM".

Sammy! Sammy!
Why do you get all bent out of shape

Hey Pal, I ain't bent outta shape--Furthermore, *you*, Potter,
might
do some self education *before* you spew your misunderstood
assertions.

Sammy! Sammy!
Don't get all excited, and "spew your" venom.

After thinking about it,
maybe it is good that you "spew your" venom
as that might calm you down,
and keep you from getting a stroke.

I just don't want you to
invest all the money you get from Google Ad Sense
clicks on your "edu" web page
on some Russian scam.

I bet that Russian "spoofer"
( It is NOT a "jammer". ) could
"EFFECTIVELY DENY USE OF GPS"
as far away a several light years,
if a good RADAR duct existed.

I will be looking forward to seeing my pal Sammy,
correct "spew" by rationally examining the "spew"
rather than irrationally attacking the "spewer".

Your pal,
Detecting IED's is a very serious topic and you two have polluted it
by arguing about jamming GPS systems. What do GPS systems have to do
with IED's?
We should all be straining our brains to think of a counter measure to
the IED, but nobody is going to read this overly long harangue more
than once, when they find out it's way OFF TOPIC.
How can we frustrate the IED's?
One suggestion might be for the cell tower be notified of the
explosion and quickly (using a simple cache system) store all the
current phone numbers, to provide a clue to the one sending the
message. Something, anything.

As I posted in my first post to this thread:
============================

"A system to prevent cellphone activated IEDs would need to:
1. Monitor all cell phone spectrum signals in the area.
2. Find ALL of the Barker Code headers (By cross-correlating).
3. Generate and retransmit signals on ALL of the signals
that override the data trailing the Barker Code,
so that the IED would not know that it was being sent
a signal to detonate.

And all this would have to be done fast enough
to prevent ONE detonation signal from getting through.

And you're incorrect. There are devices designed
for this purpose which do not have to go through
all this rigmarole.

Do a web search if you're curious, instead
of making stuff up. Try "IED jammer".

How soon they forget!

Randy,
as I posted on 10/25.
================

"Sammy, if I were trying to jam nearby GPS receivers,
I might use a transmitter tuned to the GPS band
to "saturate the RF sections",

and if I were trying to jam all of the GPS receivers
in a region to neutralize GPS controlled weapons,

I would use several geographically distributed
receiver/transmitters to receive and retransmit
the entire band in order to make it difficult
for any GPS receiver to get a lock on the
right signal,

if I were designing a system to set off an IED,
I would have it monitor strong approaching near field
transmission, and explode when the transmitter was near.

For example, I might set it to trigger
on the downslope of the jamming signal.
( After the jammer passed over or by the IED.)"

And as I posted on 10/28.
==================

"An ad for a commercial "jammer" is listed below.
Note that it takes 1000 Milliwatts ( One watt)
of RF power to jam receivers about 50 feet away.

And note that the power spreads out as a function of
the square of the distance, so it would take
4 watts to jam a receiver 100 feet away,
16 watts to jam a receiver 200 feet away,
64 watts to jam a receiver 400 feet away, etc.

Ad for a GPS Jammer.
==============================
Big Power GPS Jammer
Description:
Total Output Power: 1000 Milliwatts
Effective distance: 0 to 15 metres (in optimum conditions)
==================="

Randy, as digital communications is hard to "jam"
as it is designed to extract signals buried deep in the noise,
and as the strength of a signal falls off as a function of
the fourth power of the distance,

it takes a lot of power to jam digital receivers.

As I pointed out,
a "spoofer" will work over a much wider range,
as the "spoofing" signal confuses the correlators used
to identify the right signal and extract the digital data.

And note, that as I pointed out,
a "spoofer" takes time to figure out what signal
it is trying to "spoof", and the IED would
receive the triggering signal BEFORE the "spoofer"
was able to receive and retransmit the short, one time,
triggering signal.

And as I posted:

"if I were designing a system to set off an IED,
I would have it monitor strong approaching near field
transmission, and explode when the transmitter was near."

Can you imagine how much it would cost
to put "jammers" capable of "jamming"
at a useable range, in all of the Military's vehicles?

And you are assuming that the guys who design the IEDs
are ignorant, and do not know how to build devices that
operate out of the frequency band of the "jammer".

Rational, intelligent, SANE people understand
that if you send an army into a territory
and have to support over long distances,
and you piss off the folks in the occupied territory,
that they will not allow you to live off the land,
and they will pick off your personnel, one by one.

The choices are:

1. Don't do it.

2. Do like the Romans and Genghis Kahn,
swoop in, conquer, set up a government
consisting of locals, get out, and collect booty (Oil, etc.).

3. Swoop in. Kill all of the people in the area.
This works for stealing natural resources,
and using your own people and resources to do the work,
but it wouldn't work where you want to
steal the work product of the locals.

--
Tom Potter

http://home.earthlink.net/~tdp
http://notsocrazyideas.blogspot.com/



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Relevant Pages

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