What is RF Jamming?

RF Jamming, or Radio Frequency Jamming, is the concept of blocking a wireless device from communicating with other devices or a wireless network. This is usually done in environments that require high security, and any undesired communication needs to be stopped. In order to block the communication between a device and other external devices, equipments called “RF Jammers” are used. These RF Jammers transmit signals of very high-power – compared to the signals from the device that needs to be jammed – on the same frequency as the device that is being jammed. The combination of very high-power signal on the same frequency overwhelms the receiving device and makes it unable to decode any target signals.

RF Jamming is a common tool used in electronic warfare or during tense relations between countries. In fact, RF Jamming was introduced for military applications and continues to be dominantly used by militaries of various countries and the unauthorized use of RF Jammers by civilians is illegal in many countries.

RF Jamming and interference were considered to be one and the same since the process of jamming includes interference of signals. However, in recent times, users term “jamming” as deliberate blocking of signals whereas “interference” is referred to accidental/unintentional disruption of signals in an area. Unintentional disruption of signals can be caused by equipment malfunction, operator’s mistake, among other reasons. Increasing number of both low and high-powered wireless devices also contribute to unintentional disruption of signals.

Types of Jammers

• Portable Jammers: These are compact and low-powered (relatively) devices that can fit in the palm of our hands. Portable Jammers – as the name suggests – are designed to be moved around without any hassle. They are low-power battery-operated devices which can block devices within a few meters.
• Stationary Jammers: Stationary jammers are powerful equipments which are permanently installed in a designated area. They can transmit very high-power signals for RF Jamming across a range of frequencies and can achieve signal blocking radius of hundreds of meters. These jammers usually require an AC supply.

RF Jammers can also be made by individuals using basic electronic circuits. They consist of three main sections:

• Power Supply: It provides the required DC voltages to the various sections of the circuit.
• IF Section: It generates IF frequency by tuning VCO module as required.
• RF Section: This section converts the IF frequency to the desired output frequency, followed by amplification of the signal and then transmission via an antenna.

How to Avoid RF Jamming

In response to RF Jamming being used widely for military applications, security tool designers have also come up with various ways to counter RF Jamming. Although, most of those techniques are proprietary and not open for the world to grab that knowledge. There are general ways of paving a path around RF Jamming equipment. These include the use of numerous narrow bandwidth signals with short bursts of transmission which makes jamming more difficult.