Drone jammers are also a necessity in prisons. Authorities have confiscated more than 6,000 cellphones in North Carolina’s 55 prisons since 2005, including 443 so far this year. The numbers rose steadily until 2012, when authorities implemented airport-like entrance and exit procedures, such as metal detectors, X-ray scanners and trained dogs, at higher-security prisons. A state law passed after Janssen’s kidnapping that made it a felony to provide a cellphone to a prison inmate also served as a deterrent, authorities said. Some facilities used “managed access,” an expensive system that blocks unauthorized cell signals, in portions of the prison, but Solomon said signal jamming would extend that across entire prisons and be more effective.
Many detainees continue to organize their illegal drug trades from inside prison walls. A cell phone is an essential means for the detainee to keep the drug organization running and closely controlled. By contacting visitors before they arrive, prisoners can arrange for a transfer of drugs and drug paraphernalia, allowing them to continue the same illegal habit that placed them in custody. Frequently, the family endures harassment from its incarcerated relative, demanding bail when the family recognizes the relative is better served remaining in custody.
The Russian army has established a ground-based unit specializing in defeating enemy drones. The unit—the first of its kind in Russia—operates electronic jamming systems that, in theory, can sever the radio connections between unmanned aerial vehicles and their operators.
Usually, in the Anti-Drone application, the intention is to jam the Drone when it is hundreds of meters away from the sensitive area/perimeter (where the Jammer is installed). For example, we want to jam a Drone, which is 300 meters away from the drone jammer and flying at an altitude of 10 meters. As can be understood, in this case the diagonal distance between the Jammer and the Drone is about the same as the horizontal distance between them. Therefore, in order to simplify things, we will be discussing horizontal distances and we will not bother our selves with calculating the exact distance, because the difference is quite small.
Sometimes the jamming signal arriving at the receiver input, can be lower than the communication (“partner’s”) signal and still prevail. This is happening because usually the receiver needs a certain “margin” between the two signals at its input, in order to be able to interpret one of them (usually the stronger one). However, in advanced communication systems, this “margin” can sometimes be even negative (meaning that the communication signal can be much lower than the jamming signal), and the receiver will still be able to interpret the “partner’s” signal, making jamming a much harder task