US drone video feed intercepted by insurgents
Those likely to be targeted by U.S. drones are using cheap downloadable software to intercept and watch the video in real time as it is transmitted to ground controllers. This ability effectively neutralises the drones as a weapon. The U.S. military has been aware of this for some time and is addressing the vulnerability.
Drones such as 'Raptor' and 'Reaper' are effective for surveillance and attack in large part because they are unseen and unheard. Flying at low speed they are able to loiter over an area for hours observing the ground below. Unlike conventional military aircraft, drones are incapable of quickly zooming in for what amounts to a surprise attack. Drones instead rely on stealth, those on the ground not realising they are being observed.
It is possible to detect unseen aircraft, however. Radar is the obvious means of detection but there is a low-tech alternative: listening. Back in the days before radar, sound amplification devices - essentially gigantic ear trumpets - were used to detect the sound of approaching aircraft. It seems only logical to assume that even a simple ear trumpet would enable those on the ground to detect the engine noise from loitering drones. A drone thus detected would be useless.