July 3, 2011: After eight years of effort, and $17 billion, the United States has reduced the effectiveness of roadside bombs, but not eliminated them. These weapons have been around for over a century. But in Vietnam, only 14 percent of combat deaths were from roadside bombs, compared to 50-60 percent in Iraq and Afghanistan. That's because U.S. combat troops are a lot more deadly now, and the Iraqis and Afghans find that fighting the Americans directly is suicidal. So the roadside bombs, and suicide bombs, are seen as a more viable approach. But the Americans have responded with several generations of jammers, that have made roadside bombs more difficult, and deadly, to use.

For example, one reason so many roadside bombs in Afghanistan use pressure plates or wire controlled devices to detonate these weapons, is because American jamming technology has made wireless detonation of the bombs so difficult. The Taliban had another advantage in that there was not a lot of old artillery ammo to use for bombs, so they had to use fertilizer bombs and all sorts of improvisations, that negated techniques developed for Iraq. Still, the roadside bombs remained a last-ditch weapon of terrorists who had no other alternatives.

The U.S. Department of Defense is working on a third generation of jammers, to make sure the terrorists have to rely on less effective means of detonating their bombs for the foreseeable future. There is also an effort to make the jammers capable of collecting and analyzing electronic information (to locate the terrorists) or even prematurely detonate some bombs.

The most recent jammer innovation is the JCREW (Joint Counter Radio-Controlled Improvised Explosive Device Electronic Warfare) dismounted (wearable) jammer. These cost about $99,000 each. The wearable JCREW jammers are more useful in Afghanistan, where more of the patrolling is on foot. Five years ago, the U.S. began using wearable JCREW jammers, and these have gotten lighter, more reliable and more capable. JCREW is a further development of the first jammer, the Warlock, which appeared in 2003, mounted in vehicles. The jammers have gone through many revisions, to add more frequencies and better software.

Rolling along in a convoy, with one or more jammers broadcasting, the troops have an electronic "bubble" that made them safe from any wireless IED they had not spotted. It's not uncommon for vehicles to have had an IED go off behind them, the result of the IED detonation crew continuing to send the signal, believing that there might be something wrong with their equipment. In those cases, the patrol often turns around and goes looking for the enemy team. Supply convoys just continue on their way.

In addition to jammers like JCREW and Warlock, several of the U.S. Air Force and Navy electronic warfare aircraft are able to perform the same functions, but over a wider area. This was often used when American troops were in action against the enemy, shutting down IED detonation over the entire combat area, as U.S. troops moved around seeking out and fighting the enemy.

One problem with the jamming was that it kills cell phone operation, as well as use of many other remote electronic devices Iraqi civilians in the area might be trying to use. The locals complain to each other, but asking the U.S. troops to shut it off would be futile, so they don't.

The current JCREW jammer has lots of new features, most of which are secret. Terrorist groups have tried to find ways around the jammer, but have been unsuccessful. Most roadside bombs are now set off via a wire connection between the detonator and a nearby guy pressing a button. This has caused more terrorist casualties, and generally made it more difficult for the bombers. Pressure plate detonation is less popular because the terrorists have no control over when the bomb goes off, and when it's a civilian vehicle getting blown up by mistake, the Taliban drop further in the opinion polls.

The big (non-secret) improvement in JCREW is that it is easier to add new frequencies, and the jammer interferes less with other military communications and sensors. JCREW is also lighter. There are always new versions of JCREW being sent out for testing. For example, a hundred or so lightweight JCREW jammers were first sent to Iraq three years ago, for testing. These proved very popular with troops who did a lot of their patrolling on foot. It's become increasingly common for troops to make long movements on foot, to conduct raids or just patrol. The enemy has lookouts who are on the alert for U.S. vehicles, not dismounted American infantry sneaking up on them.