The role of the signal jammer is to break the communication link (or network) between two (or more) "partners" when they are trying to talk to each other or transfer certain data between them. Disrupting the communication link between a drone and its operator is a specific case of much more; we can try to disrupt communications between a cellular device and the base station, between two tactical radios, between a bomb and a remote control that is used to activate it.
Sometimes the interference signal arriving at the receiver input can be lower than the communication signal ("partner") and still prevail. This happens because the receiver normally 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). In advanced communication systems, however, this "margin" can sometimes even be negative (which means that the communication signal can be much lower than the interference signal), and the receiver will still be able to interpret the "partner" signal, thus Disturbances caused are much more difficult task.
