Fading Signal: The Neglect of Electronic Warfare.

"Juergen Nieveler" wrote in message
. ..

BTW, do those jammers send white noise, or are they smart enough to
fake a signal? Say, I build a small detonator from RC car parts, and it
depends on the transmitter sending "left, right, left..." every 30
seconds, with a timer starting on every signal, counting down until the
opposite side timer is started.

With a white noise jammer, no signal gets through anymore, 30 seconds
later you get *bang*...

All this stuff came out at the inquest into the people shot in Gib. The
claim was made that the security forces should be able to jam the signal.

They explained in some detail why they couldn't.

It seems that the IRA people used a Trio Radio Amateur 144 MHz pocket radio
system that requires a sequence of reversals transmitted by VHF FSK to
trigger an open channel. The sequence is set by a row of five thumbwheels,
each of ten digits.

So you've got a million, minus one, possible combinations.

I leave as an exercise for the reader the calculation of the linear
recursive sequence necessary to trigger the thing prematurely...

This, of course, assumes the security forces know the radio frequency and
the FSK baud rate and frequency shift.

White noise generators don't work once the bad guys get up to 'radio
amateur' levels of knowledge of triggering technology...

--
William Black


I've seen things you people wouldn't believe.
Barbeques on fire by the chalets past the castle headland
I watched the gift shops glitter in the darkness off the Newborough gate
All these moments will be lost in time, like icecream on the beach
Time for tea.

On Apr 8, 7:41*am, "William Black"
wrote:
"Juergen Nieveler" wrote in message

. ..



BTW, do those jammers send white noise, or are they smart enough to
fake a signal? Say, I build a small detonator from RC car parts, and it
depends on the transmitter sending "left, right, left..." every 30
seconds, with a timer starting on every signal, counting down until the
opposite side timer is started.

With a white noise jammer, no signal gets through anymore, 30 seconds
later you get *bang*...

All this stuff came out at the inquest into the people shot in Gib. The
claim was made that the security forces should be able to jam the signal.

They explained in some detail why they couldn't.

It seems that the IRA people used a Trio Radio Amateur 144 MHz pocket radio
system that requires a sequence of reversals transmitted by VHF FSK to
trigger an open channel. *The sequence is set by a row of five thumbwheels,
each of ten digits.

So you've got a million, minus one, possible combinations.

I leave as an exercise for the reader the calculation of the linear
recursive sequence necessary to trigger the thing prematurely...

This, *of course, assumes the security forces know the radio frequency and
the FSK baud rate and frequency shift.

White noise generators don't work once the bad guys get up to 'radio
amateur' levels of knowledge of triggering technology...


Gibraltar was 20 years ago. They've learned a lot since then and
deaths from IED's have dropped dramatically since the USN's EW experts
have trained the soldiers to use the equipment correctly.

"They called themselves "sand sailors," and they did their job well by
reducing IED fatalities at their bases. Monthly U.S. troop deaths from
IEDs have dropped since reaching a high of 90 in May to 17 last month,
in part because of their efforts, the military said in awarding Bronze
Stars to Dye and others."

http://www.boston.com/news/nation/ar...ead_ied_fight/


BB

I guess everybody has some mountain to climb.
It's just fate whether you live in Kansas or Tibet...

"BlackBeard" wrote in message
...
On Apr 8, 7:41 am, "William Black"
wrote:
"Juergen Nieveler" wrote in message

. ..



BTW, do those jammers send white noise, or are they smart enough to
fake a signal? Say, I build a small detonator from RC car parts, and it
depends on the transmitter sending "left, right, left..." every 30
seconds, with a timer starting on every signal, counting down until the
opposite side timer is started.

With a white noise jammer, no signal gets through anymore, 30 seconds
later you get *bang*...

All this stuff came out at the inquest into the people shot in Gib. The
claim was made that the security forces should be able to jam the signal.

They explained in some detail why they couldn't.

It seems that the IRA people used a Trio Radio Amateur 144 MHz pocket
radio
system that requires a sequence of reversals transmitted by VHF FSK to
trigger an open channel. The sequence is set by a row of five thumbwheels,
each of ten digits.

So you've got a million, minus one, possible combinations.

I leave as an exercise for the reader the calculation of the linear
recursive sequence necessary to trigger the thing prematurely...

This, of course, assumes the security forces know the radio frequency and
the FSK baud rate and frequency shift.

White noise generators don't work once the bad guys get up to 'radio
amateur' levels of knowledge of triggering technology...


Gibraltar was 20 years ago. They've learned a lot since then and
deaths from IED's have dropped dramatically since the USN's EW experts
have trained the soldiers to use the equipment correctly.

"They called themselves "sand sailors," and they did their job well by
reducing IED fatalities at their bases. Monthly U.S. troop deaths from
IEDs have dropped since reaching a high of 90 in May to 17 last month,
in part because of their efforts, the military said in awarding Bronze
Stars to Dye and others."

----------------------------

Almost certainly the big drop was caused by training people how to spot the
bloody things.

Messing with the trigger mechanism is very much a secondary thing, the best
solution is not to park next door to one...

--
William Black


I've seen things you people wouldn't believe.
Barbeques on fire by the chalets past the castle headland
I watched the gift shops glitter in the darkness off the Newborough gate
All these moments will be lost in time, like icecream on the beach
Time for tea.

On Apr 8, 9:15*am, "William Black"
wrote:


Almost certainly the big drop was caused by training people how to spot the
bloody things.


Not according to the article.

"Thomas said the technology works by "basically providing a protective
bubble around a vehicle," jamming incoming signals and blocking the
remote detonation of bombs."

BB

I guess everybody has some mountain to climb.
It's just fate whether you live in Kansas or Tibet...

"BlackBeard" wrote in message
...
On Apr 8, 9:15 am, "William Black"
wrote:


Almost certainly the big drop was caused by training people how to spot
the
bloody things.


Not according to the article.

"Thomas said the technology works by "basically providing a protective
bubble around a vehicle," jamming incoming signals and blocking the
remote detonation of bombs."

-----------------------

If that's the case then expect the lull to last for only a couple of months,
until the bad guys get hold of a technology that works.

--
William Black


I've seen things you people wouldn't believe.
Barbeques on fire by the chalets past the castle headland
I watched the gift shops glitter in the darkness off the Newborough gate
All these moments will be lost in time, like icecream on the beach
Time for tea.

In message , William Black
writes
"BlackBeard" wrote in message
...
Not according to the article.

"Thomas said the technology works by "basically providing a protective
bubble around a vehicle," jamming incoming signals and blocking the
remote detonation of bombs."

-----------------------

If that's the case then expect the lull to last for only a couple of months,
until the bad guys get hold of a technology that works.

Whereupon the ECM gear will be modified to suit. The kit being used in
2005 is pretty much obsolete now... the WIS guys don't sit on their
laurels either.

--
The nation that makes a great distinction between its scholars and its
warriors, will have its thinking done by cowards and its fighting done
by fools.
-Thucydides


pauldotjdotadam[at]googlemail{dot}.com

"Paul J. Adam" wrote in message
...
In message , William Black
writes
"BlackBeard" wrote in message
...
Not according to the article.

"Thomas said the technology works by "basically providing a protective
bubble around a vehicle," jamming incoming signals and blocking the
remote detonation of bombs."

-----------------------

If that's the case then expect the lull to last for only a couple of
months,
until the bad guys get hold of a technology that works.

Whereupon the ECM gear will be modified to suit. The kit being used in
2005 is pretty much obsolete now... the WIS guys don't sit on their
laurels either.


True.

But the countermeasures people have to react. It's not something you can be
proactive about...

--
William Black


I've seen things you people wouldn't believe.
Barbeques on fire by the chalets past the castle headland
I watched the gift shops glitter in the darkness off the Newborough gate
All these moments will be lost in time, like icecream on the beach
Time for tea.

BTW, do those jammers send white noise, or are they smart enough to
fake a signal? Say, I build a small detonator from RC car parts, and it
depends on the transmitter sending "left, right, left..." every 30
seconds, with a timer starting on every signal, counting down until the
opposite side timer is started.

With a white noise jammer, no signal gets through anymore, 30 seconds
later you get *bang*...


But that is not a system that you would want to use for real, any kind of
failure or signal interuption would cause a detonation.


All this stuff came out at the inquest into the people shot in Gib. The
claim was made that the security forces should be able to jam the signal.

They explained in some detail why they couldn't.

They certainaly could jam the signal, what they could not do eaisly is
detonate the device when they wished.

It seems that the IRA people used a Trio Radio Amateur 144 MHz pocket
radio
system that requires a sequence of reversals transmitted by VHF FSK to
trigger an open channel. The sequence is set by a row of five thumbwheels,
each of ten digits.

So you've got a million, minus one, possible combinations.

I leave as an exercise for the reader the calculation of the linear
recursive sequence necessary to trigger the thing prematurely...

This, of course, assumes the security forces know the radio frequency and
the FSK baud rate and frequency shift.

White noise generators don't work once the bad guys get up to 'radio
amateur' levels of knowledge of triggering technology...


White noise will *allways* work as long as you can get a loud enough signal,
its just a matter of power and range.
However, the more intelligent jammers use other signal patterns to jam known
types of transmission, and "look through" their own transmissions to analyze
the target signal.

Jeff

All this stuff came out at the inquest into the people shot in Gib. The
claim was made that the security forces should be able to jam the signal.

They explained in some detail why they couldn't.

They certainaly could jam the signal, what they could not do eaisly is
detonate the device when they wished.

It seems that the IRA people used a Trio Radio Amateur 144 MHz pocket
radio
system that requires a sequence of reversals transmitted by VHF FSK to
trigger an open channel. The sequence is set by a row of five
thumbwheels,
each of ten digits.


As a matter of interest the bomb intended for Gibraltar was NOT radio
controlled, it was a timer device that was found in the car (still in
Spain).

The SAS did not know this, however, and were acting on what had become
common practise for the IRA in N Ireland from the mid 70's, which was to use
radio control.

Jeff

Jeff wrote:
BTW, do those jammers send white noise, or are they smart enough to
fake a signal? Say, I build a small detonator from RC car parts, and it
depends on the transmitter sending "left, right, left..." every 30
seconds, with a timer starting on every signal, counting down until the
opposite side timer is started.
With a white noise jammer, no signal gets through anymore, 30 seconds
later you get *bang*...


But that is not a system that you would want to use for real, any kind of
failure or signal interuption would cause a detonation.
[snip]


Providing they kill someone they do not care. Terrorist organisations
have repeatedly show that they consider local civilians to be targets.
Western soldiers are just higher valuse targets.

Andrew Swallow