In the last six years, the U.S. Department of Defense has spent billions of dollars on electronic jammers, used to prevent roadside bombs from detonating via wireless devices (everything from cell phones to door bells and toys). These jammers worked, but there was one downside. Some models jammed the same frequencies used by American military radios. This was not as much of a problem as you might think, as U.S. military radios are designed to keep functioning when the enemy uses jammers. But this feature never got as much of a workout as it did when confronted with the many models of jammers delivered to the troops in Iraq and Afghanistan. The jammers not only interfered with radios, but also with wireless communications with UAVs and ground robots, as well as electronics on nearby navy and air force aircraft. The latter two services sent in many of their own electronics experts to help the army develop solutions for the "friendly jamming" problem.
Most of the major friendly jamming problems have been solved. When they weren't, the troops always had their hand signals (which are still taught) to fall back on. But since the enemy is always going to try new wireless devices, some of them specially tweaked, for their bombs, the jammers are going to be tweaked in turn. Every time this happens, there's the unanticipated risk of some piece of equipment getting jammed unintentionally. Fortunately, these jammers have a short range (a kilometer or so). But as vehicles move along, with their jammer going, the electronic "bubble" also jams most civilian communications it comes into contact with (especially cell phones). This annoys the civilians, but they just have to live with it. And sometimes they owe their lives to it, because roadside bombs continue to kill more civilians than their intended military personnel targets.