A RF Jammer is a device that people use to disrupt or hamper communication via a broadcast Radio Frequency signal. Radio Frequency jamming technology employs the fact that mobile phones work by communicating with a service network via cellular towers, sometimes known as base stations. Each of the towers divide the city they are installed in into small sections known as cells. When a cell phone user walks by or through the cells in any area, the Radio Frequency gets transmitted from one tower to the other.

The Radio Frequency jamming devices exploit this fact, and thus transmit on the same spectrum as that of cellular devices. Through the concurrent transmission, the jamming device is thus able to disrupt a two-way communication between a phone and the base station.

However, RF jamming is not confined to cell phone jamming. Any communication which employs the use of radio frequencies is susceptible to jamming by a stronger radio signal transmitted in the same radio frequency spectrum. Thus, radar signals can be jammed. Wi-Fi connections are also prone to network jamming attacks, consequently reducing the Wi-Fi signal quality until it becomes totally unusable or it disconnects. Similarly, a focused and aimed signal has the potential to break access point hardware.

Radio Frequency jamming can be malicious or benign. For example, security forces and the military can use the jamming devices to hamper communication if there is a hostage situation, bombing threats, or during intensified military action. Radio Frequency devices have also been used by anti-riot police to quell protests during demonstrations. Worldwide, the most useful application of RF jammers has been to hinder the use of cell-phone activated bombs in airports, subways, or even the routes of presidential motorcades.

With portable RF jammers, owners can be able to prevent other people in their immediate vicinity- 60 to 80 feet away- from using their mobile phones. Jammers find use in theatres, churches, operating rooms, secure server rooms and any other environment where Wi-Fi and cell phone communication is not welcome.

There are people who may put the jammers into malicious use to prevent other people from communicating freely as they should. There are a variety of ways to detect and prevent the radio frequency jammer attacks. Wireless intrusion prevention systems (WIPS) can monitor the radio spectrum throughout, thus, revealing a signal jammer when there is one. There are also radio-based devices which support Spread Spectrum Modulation that enables the hardware to cycle through various frequencies therefore making the respective device harder to jam.

To prevent outside radio frequency jammer attack, the use of paint that has copper flakes is crucial. Using paint that has copper flakes is an effective way to prevent signals from penetrating walls. This is a passive and permanent way to cushion one’s devices from intrusive radio frequency jamming attacks. If a person needs complete protection from jamming attacks, Faraday cage can stop any form of wireless signal from penetrating through the walls.

Radio frequency jammers cannot be legally sold because they violate some regulations regarding communication equipment. That notwithstanding, there are plenty of instructions and guidelines on how to make a radio frequency jammer.