Mysterious Cell Towers Throughout US

Popular Science magazine recently published an article about a network of cell towers owned not by telecommunication companies but by unknown third parties. Many of them are built around U.S. military bases. "Interceptors vary widely in expense and sophistication – but in a nutshell, they are radio-equipped computers with software that can use arcane cellular network protocols and defeat the onboard encryption. ... Some interceptors are limited, only able to passively listen to either outgoing or incoming calls. But full-featured devices like the VME Dominator, available only to government agencies, can not only capture calls and texts, but even actively control the phone, sending out spoof texts, for example.