Posted on 04/05/2004 3:24:14 PM PDT by demlosers
DefenseNews March 22, 2004
But Terrorists Keep Working To Thwart Latest Defenses
For ambassadors, oil executives, heads of state and, increasingly, U.S. troops, the list of essential security gear now includes a bomb jammer.
New models small enough to fit into a briefcase or a backpack are being supplied to U.S. military convoys in Iraq to prevent roadside bombs from detonating as troops drive past.
Jammers are also being snapped up by businessmen, diplomats and political leaders, said Ben Jamil, whose company, Security Intelligence Technologies Inc., is selling three new types of bomb jammers – the VIP 2, VIP 3 and the VIP 16 – to anxious buyers from Latin America to the Middle East.
“Every embassy, every oil company – if you’re I the Middle East and you don’t have one, you should leave,” Jamil said during an interview from his New Rochelle, N.Y., headquarters.
Pakistani President Gen. Pervez Musharraf is likely alive today because his motorcade was equipped with a bomb jammer that prevented the explosion of five radio-controlled bombs hidden on a Rawalpindi bridge last Dec. 14.
In the aftermath of the attack, Pakistani officials described the president’s bomb jammer as capable of blocking radio transmissions within 200 meters of the president’s limousine. When Musharraf’s motorcade had moved about 200 meters past the bombs, they exploded. Non one was hurt because the bridge had been closed to traffic.
While U.S. troops in Iraq have begun using bomb jammers, the numbers remain small, according to Rep. Gene Taylor, D-Miss.
“The percentage of vehicles that have some form of electronic jammer – it is minuscule,” Taylor said during a House Armed Services Committee hearing in February.
How They Work Roadside bombs have killed more than 100 U.S. troops and wounded more than 1,100. Many are detonated by insurgents using cellular telephones, remote controls for toys, garage door openers and car alarm controls.
In each case, a transmitter sends an electronic signal to a receiver, which triggers the bomb.
Bomb jammers generally work by transmitting a signal that is the same frequency of the signal intended to detonate the bomb. The jamming signal interferes with the detonating signal, but since it is usually random noise, doe not, itself, trigger the bomb. Some, however, are a bit more sophisticated.
“Our jammers are radio-detection systems,” Jamil said. “They are constantly scanning the spectrum of radio frequencies, and when they spot a signal, they immediately analyze it and jam it” if it is suspected to be intended for detonating a bomb. In some instances, the signal from the jammers can “overload the receiver” and detonated the bomb prematurely, he said. In that case, the bombs go off before U.S. troops arrive.
In addition to jamming improvised bombs and radio-controlled mines, the jammers can block electronic surveillance devices, such as hidden video cameras, and eavesdropping devices planted in homes, cars, offices, hotels and conference rooms, he said.
“I’ve heard of situations where jamming has covered 30 square miles,” he said. But more commonly, jamming signals cover about 30-500 meters.
Security Intelligence Technologies’ jammers include:
The VIP 2, which weighs 22 pounds, comes in a briefcase and is intended for “defenseive situations of relatively short duration” such as travel by executives and diplomats, according to the company. It costs about $20,000. The VIP 3 costs twice as much, also comes in a briefcase, and is intended for clearing vulnerable locations and for protecting troops and military equipment as they move through dangerous areas. The CIP 16 jammer is powerful enough to be used from helicopters or unmanned aerial vehicles, according to Security Intelligence Technologies. It has been used in Lebanon, where antennas are set up at thousand-yard intervals along a road to provide a safe route for convoys, Jamil said. It can also be placed around buildings to keep bombs from exploding, and is expected to be used at the Olympics in Athens this summer, he said. The jammers have not been approved by the Federal Communications Commission, so are not for sale to U.S. consumers. They are available to law enforcement agencies, Jamil said.
Bomb jammers have been around for 30 or 35 years, but only in the past year with the proliferation of improvised explosive devices in Iraq have the gotten much attention.
Bombs triggered by cell phone are the latest threat. Those include Iraq’s roadside bombs and terrorist car bombs, Jamil said.
Use of bomb jammers by U.S. troops in Iraq “has proven fairly effective” for protecting the convoys that have them, said François Boo, an associate at GlobalSecurity.org, a defense policy organization in Alexandria, Va.
But the increased use of bomb jammers has touched off an arms race of sorts. “As the U.S. figures out how the insurgents operate, the insurgents figure out new ways” to trigger their bombs, he said.
Jamil agreed. “The problem is, every time we plug a hole, they come up with something different. We’re chasing our tail. It’s not a hundred percent solution for terrorist, but it’s still important.”
Although Security Intelligence Technologies is pushing its briefcase bomb jammers, another variety is proving to be increasingly popular among diplomats and business executives, Jamil said. It’s a bomb jammer that comes installed in the trunk of a bullet-resistant armored car.
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Really simple stuff.
And if they go to using wires, then the bombers are easier to find since they have to be nearby.
But then it's always a (deadly) game between the makers of counter-measures and the makers of counter-counter-measures, isn't it?
Not very acurate but it is a timing device.
The normal frequencies for remote controls are 433Mhz (data), 27Mhz (RC cars) and few others. These are off the shelf transmitters from off the shelf products.
Jammers focus on these.
There is no jammer that will work and jam across the whole communication spectrum i.e. 30Mhz radio up to 900Mhz mobile phone as it will be blocking their own comms as well.
Make custom made transmitter at odd frequency and it will work. But this is expensive. :))
Now you're talking anti-jam, really classified stuff. But your wrong, really good jamers can be designed that work the whole spectrum, jump fast to required frequencies, and have frequency holes made for our comms. But these convoys probably don't use comms much, I get the feeling they are just trucks going somewhere, and don't prepare as much as they should.
I am a electrical engineer doing embedded design and I can not understand how this works:
“Our jammers are radio-detection systems,” Jamil said. “They are constantly scanning the spectrum of radio frequencies, and when they spot a signal, they immediately analyze it and jam it” if it is suspected to be intended for detonating a bomb.
The jammer as he sais is a reciever and the bomb is the reciever as well.
When a button is pressed to detonate a bomb and if the jammer has managed to get a signal and finds its frequency in order to jam it, the bomb has ALSO recieved the command and it is detonating.
The above works to block communications but not a bomb command. When comms get transmitted jamming reciever locks on the frequency and jams it and further comms is disabled.
But a bomb needs a single command only.
I say it would be very difficult to prevent a profesional made device.
He is looking at the car approaching. When he thinks that the car is at the right place he presses the button.
Signal/pulse travels and as jammer is ON the signal is prevented from reaching reciever. Reciever has filter for that frequency and all it gets is noise.
Bomber sees no explosion and presses again and again until bomb goes OFF when jammer range is weak i.e. 50-100m away.
Don't think a signal is delayed. A signal is instatenous and either gets there or not.
If I was doing it I would use exactly the same stuff as the Musharrafs case BUT with a little simple cheap addition which would make it simple but deadly and there is no defence as far as I can think of.
I am not sure if we should be talking about this anyway :))).
I say it would be very difficult to prevent a profesional made device.
Yes, but the bombs we are talking about are not prefessional made devices, the bomber takes a garage opener or cell phone receiver and puts it in the bomb.
The device has a circuit that recognizes a pattern in the airwaves that triggers a response. The bomber must be smart enough to connect this response to a detonator.
To defeat the device, one jammer could receive transmitted signals, and before the pattern is completely sent, add some "pattern" of its own. Now the bomb receiver does not see the right pattern. The jammer and bomber will repeat this sequence as many times as necessary. Imagine your neighbor's frustation if you had such a device and could prevent them from opening their own garage.
Another approach to defeat the device would be to send random patterns on lots of frequencies, (garage door openers do not have many digits in their pattern and are on several assigned and thus known frequencies.) Now the bomb sees the pattern and goes off prematurely. See the pattern? No I am not saying this is easy, but we have lots of designers attacking the problem from every different angle. I am only surprised that it took so long to get it done.
These have 4 filters for lets say 4 direction movements. Any signal in that range will trigger the reciever.
Hell a jammer signal in that frequency will trigger it.
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