The purpose of a signal jammer is clear: interrupt communication between two devices. This dreaded device is the worst enemy for any alarm, locator or anti-theft device in general. Because of that, they are broadly used by thieves to steal all sorts of objects, mainly cars and motorcycles, and to deactivate alarms from our homes. The purpose of this post is to display how these simple and effective devices operate, and how Mapit’s technologies have been successful in overcoming them.

The key aspect is in the electromagnetic noise they produce, which blocks the frequency. Roughly speaking, they generate “useless information” that is introduced inside the frequency of any device that is near them, which prevents them from receiving real information. So basically, they operate by saturating the channels of the receiving devices.

A similar situation would be that of a person who is listening to music with headphones. In this case the signal jammer would be the head phones, so that when someone is using them he or she can´t listen to anything that goes on around them. This mechanism of signal blocking often affects security systems that need to receive information from the antennas located in base stations to be able to emit all sorts of messages.

What types of signal jammers exist?

Besides its main characteristics, we can classify them according to two criteria: bandwidth and processing power.

The bandwidth is the frequency at which they can emit, and there are several of them in telephony (800MHz, 900 MHz, 1500 MHz, 1800 MHz …). According to this, some can cover only one of these and others have the ability to cover the entire spectrum, being able to block any type of frequency. On the other hand, regarding the power, the more power one has, the greater the ability to inhibit any signal. Going back to the example of headphones and music, in this case we can compare a low power inhibitor to a headset, and a high power one to a concert loudspeaker. The good news is that even the most powerful inhibitor is limited in scope to relatively short distances (the maximum length being around ten meters).


Why is Sigfox not affected by these devices?

Sigfox is the technology behind the first line of Mapit devices that we created. For those who are not familiar with it, it is a radio communication system that displaces itself with respect to 3G systems (used traditionally in GPS applications). The advantage in using devices based on Sigfox technology is that they are almost impossible to block. This is because the device, unlike GPRS systems, does not have to receive information from the antenna to work. It does not “listen”, it only emits. Therefore, it cannot be blocked in the sense that the inhibitor should be close to the receiving antenna, not the device.

Additionally, the Sigfox communications network owns more than 1300 antennas and usually messages are received by more than one of them (in some places it can even receive up to 40) and even by antennas that are tens of kilometers away. Communicating through Sigfox technologies is also an advantage because its frequency changes constantly, something that hinders signal blocking because it works with more than one at a time.

Even though there is no technology able to guarantee 100% full effectiveness, being cautious and knowing how to choose well when relying on a locator to track our motorcycle or car will make things much easier. Good luck!