Our society has become increasingly dependent on wireless technology. We wake up in the morning and check our emails over WiFi, unlock and start our cars with the key fobs in our pockets, and use our cell phones to make important calls on the way to work. When we go somewhere new, we rely on GPS to guide us. Stolen or misplaced items can be located with LoJack or wireless AirTags. On a larger scale, much of our military and civilian infrastructure relies on wireless communication. Unfortunately, these signals are vulnerable to another type of wireless device: signal jammers.

How Do Signal Jammers Work?

Generally, jammers disrupt existing wireless signals by simply drowning them out with noise. By tuning a jammer to a specific target frequency range and blasting high-powered noise, tones, or pulses, a jammer can interfere with nearby receivers that are attempting to listen on that frequency. Traditionally, this meant disrupting radio communications, but the same core principle applies to other types of wireless signals — cellular, WiFi, Bluetooth, GPS, and so on. Jammer range varies widely based on the power and scale of the device; a small handheld jammer might be effective within 100 meters or less in an urban environment, while large military-grade jammer emplacements can easily reach hundreds of miles across open terrain.

Military & Paramilitary Use of Signal Jammers

Jammers saw extensive use during WWII, when Nazis jammed Allied radio transmissions in occupied Europe, and only grew in popularity through the Cold War era. The Soviet Union and China jammed various incoming signals, Cuba blocked American radio stations, and North and South Korea jammed each other's transmissions.

A Russian Krasukha-2 anti-air jamming station. (Photo via Mil.ru, CC 4.0)

Signal jammers are still used extensively as a component of electronic warfare (EW), most notably by the Russian military. The Russians reportedly used this tech to interfere with low-altitude U.S. surveillance drones in the Syrian conflict in 2018; it's unclear whether this caused them to crash or simply veer off course. There have also been reports of Russia using powerful jammers along its eastern border, leading to disruption in Latvia's phone system and loss of GPS signal to aircraft in the area.

Closer to home, jammers have become a very popular tool among Mexican drug cartels. They seem to go hand-in-hand with another piece of tech the cartels have adopted: aerial drones.

Armed members of the Jalisco New Generation Cartel (CJNG) wearing signal jammers. (Screenshots via @just_some_d00d)

Small commercially-available drones have been used to surveil territory, especially at night with the aid of thermal cameras. They have also been weaponized to drop explosives on targets, a tactic that has previously been used by ISIS and other terrorist organizations in the Middle East. As a result, cartel members have been seen wearing man-portable signal jammers that can interfere with nearby drone uplinks as well as cellular and radio comms.

Civilian Black Market & Criminal Use

An example of a portable signal jammer available for sale on the internet, listing the frequencies it claims to block.

At this point, you may be thinking, “I'm not a high-value military target or part of a warring drug cartel, so I shouldn't have any reason to care about signal jammers.” However, this is certainly not the case. Signal jammers are inexpensive, easy to use, and readily available online to those who know where to look. They can affect your daily life in several ways — veteran-owned surveillance gear manufacturer Tiny Transmitters posted some surprising demonstrations on Instagram to prove this point.

The first demo video clip shows how a portable jammer can be tuned to the frequency of a car keyfob, blocking its signal at the flip of a switch. This means a thief could watch you park your car, turn on the jammer before you press the lock button on the fob, and prevent your car from locking. Unless you happened to notice the absence of a click or light flash from your vehicle, you'd probably assume it locked and walk away, allowing the criminal to steal any valuables in the car (or take the car itself).

Tiny Transmitters showed how a signal jammer can be used to disable a wireless doorbell camera.

Another video shows how a jammer can be used to interrupt a wireless doorbell camera by blocking its ability to communicate with the home's WiFi network. Unless the camera has a hardwired data connection — unlike most Ring, Blink, Wyze, and Nest doorbell cams — it will be unable to transmit footage to cloud servers or alert the homeowner that someone is at the door. Tiny Transmitters explains, “As you can guess, running an all-wireless household security system has a fundamental and scary flaw: the wireless signal can be jammed.”

There are many other possible applications of wireless signal jammers, from covertly blocking cell phone calls to disabling GPS tracking devices. These uses are illegal, but as we know, motivated criminals are unlikely to give a second thought to laws and FCC regulations.

Closing Thoughts

We're not here to tell you to stop using WiFi, ditch your cell phone, or throw away your ham radio — wireless devices are convenient and can be invaluable in emergency situations. However, for the safety of your family and your belongings, it's wise to keep their potential vulnerabilities in mind and take steps to limit overreliance on wireless devices.

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