Bomb Squad Diary
The Electromagnetic Struggle
The 26-ton truck rolls through a misty fog and out through a gate of Camp Speicher, near Tikrit, Iraq. On board are two U.S. Navy demolition technicians and a journalist. Their mission on this dreary January morning is “route clearance”—searching a stretch of Iraq’s main north-south highway for improvised explosive devices (IEDs).
“Hey, you wanna turn Duke on?” asks the Navy tech in the back of the heavily armored vehicle.
“No, I want us to blow up,” jokes the other tech, who’s driving the truck, as he switches on the US $80 000 electronic jammer, a breadbox-size brown metal box in a rack behind his seat. “There, does that make you feel better?” he adds.
“Yeah, actually, it does.”
Jammers like the Duke system are among the undisputed technology successes of the Iraq and Afghanistan wars. They emit enough power in specific frequency bands to simply overwhelm any signal being transmitted to a radio-controlled IED’s trigger, be it a cordless phone, cellphone, walkie-talkie, or some other receiver. Close to 40 000 jammers have been purchased for Iraq and Afghanistan; they work so well that coalition forces rarely encounter purely radio-controlled IEDs any more.
As effective as they’ve been, though, jammers are far from perfect. They have interfered with other vital radio gear, such as the standard Single Channel Ground and Airborne Radio System (SINCGARS) VHF systems on U.S. military vehicles and the radio-control links to the robots used by IED demolition teams. And they have wreaked havoc with legitimate Iraqi wireless services, like cellular telephony and emergency communications. ”The Army is using work-arounds” to minimize those problems, according to a U.S. Army electronic warfare specialist. And a more technologically advanced solution is in the works, through an R&D program called Integrated and Electronic Warfare Systems, at the Army’s Materiel Development and Readiness Command in Ft. Monmouth, N.J.
The Duke and other jammers combine active and reactive jamming techniques. An “active” jammer continuously emits radio-frequency power in certain bands and at levels strong enough to overwhelm any other signals. “Reactive” means that the jammer also monitors other frequencies and, if it detects a transmission, immediately sends out a jamming signal on those frequencies. Much of the art of jamming is devising specific waveforms and power modulation techniques. The details are all highly classified, of course.
“The electromagnetic spectrum is more and more becoming a battle space,” says Colonel Laurie Buckhout, of the U.S. Army Asymmetric Warfare Office. The goal of the effort at Ft. Monmouth will be to design jammers that can be targeted like rifles, rather than applied indiscriminately, like bombs. The idea is that these jammers will map all the radio emitters on a battlefield, discover which ones belong to the enemy, and “knock him out without knocking out anyone else,” says Buckhout. The project is part of a U.S. Army thrust into electronic warfare, traditionally a Navy domain, that has trained more than 1000 soldiers as electronic warfare officers over the past couple of years, Buckhout explains.
“The Iraq war is the first where the enemy has taken the fight to the electromagnetic spectrum, so we’ve had to go there as well,” says Buckhout, who took part in the ground war in Iraq and was later in two convoys that were hit by IEDs. “Just like you have to carefully control your fire from a kinetic weapon, artillery, or airborne attack, you have to be able to control your electronic attack as well,” she adds.