Today, let's trace the origin and development of this artifact together.
At first, the car mounted frequency blocking device for mobile phones was not actually set up for the testing site. The initial application was actually a prison.
To ensure the information security and privacy of high walled courtyards in prisons, it is necessary to isolate communication signals between prisons. This is the original intention of the onboard frequency jammer.
When the onboard frequency jammer was first invented, the world only developed into the 2G era. At that time, although there were three domestic operators, in reality, mobile phones used second-generation network communication technology. Manufacturers of different formats use good mobile communication frequencies.
Whether a mobile phone can make and answer calls mainly depends on the support of the communication base station. After the phone is turned on, it will actively connect to the nearest communication base station, and the communication base station will command it during a call. Actually, they all communicate with communication base stations. So what should a prison do if it wants to interrupt the communication between its inmates and the outside world?
The answer is actually very simple. Only one machine on the same frequency as the phone needs to make noise so that the base station can try to connect to the phone. You will find that the signals from your phone are disorganized and unrecognizable, so you will refuse to communicate with your phone.
Based on this principle, the onboard frequency jammer has been developed, and everyone is very happy. Prisons only need to be equipped with a few jammers to emit this noise to interfere with mobile communication inside the prison. And as more and more scenarios require interference signals. The vehicle frequency jammer originally designed for use in prisons has gradually entered normal commercial scenarios such as important meetings and exams.
The problem with this communication method is that the wireless version is transmitted through air, which makes the transmitted signal susceptible to interference. This interference is electromagnetic interference (EMI). signal jammer are typically used in theater to interfere with enemy forces' communication. An example of this is the Borisglobsk-2 vehicle developed in Russia, which disrupts wireless HF, UHF, and mobile communication. This is known as Electronic Warfare (EW), and this vehicle participated in the annexation of Crimea, Ukraine.
In addition to military purposes, there are other cases. An example of a civil case is the Swedish police in Stockholm, Sweden, who reported that thieves illegally used signal blocking devices to block the signal emitted by the car key, leaving the vehicle unlocked and making it easy to break in
