(CNN) -- A silent, invisible battle is being fought against roadside bombs in Iraq. Though the military doesn't like to advertise their use, electronic jamming systems are playing a key role in neutralizing the threat.
"Any weapon we had against IEDs, [Improvised Explosive Devices] was utilized including jamming technology," said Jason Spencer, 29, an Oklahoma City, Oklahoma, engineer who served with the Army in Iraq in 2005. Vehicle mounted electronic jammers attempt to block a signal going to a radio-controlled IED. The military also uses portable backpack jammers. "The sophistication of IEDs definitely increased during my time in Iraq," said Spencer. "There was a definite increase in remote detonation."
A signal going to a remote-controlled IED operates on a radio or infrared frequency. Jamming devices, known as Counter Radio Controlled Improvised Explosive Device Electronic Warfare, or CREW systems, attempt to intercept or block a signal before it reaches its intended target, preventing detonation. One common method is barrage jamming, which knocks out a broad range of radio signals. However, it also knocks out communications used by U.S. troops putting them at increased risk.
"Ideally what you want to be able to do is have something that can grab very precise signals, capture the signals and render them irrelevant without knocking out your own communication," said CNN military analyst retired Army Brig. Gen. James "Spider" Marks. These technologies represent the last line of defense, said Marks. "We don't want to give our potential enemies an understanding of what we are doing to counter their efforts," he said.
Along with jammers, troops use air surveillance, robots, blast-resistant vehicles and mine rollers as countermeasures.
