There is a kind of bad signal, called the college entrance examination two days. As a heavy mobile phone user, the battery and signal of the mobile phone are the life channel. If the battery is below 50% or the signal is not satisfactory, you will feel unhappy and insecure. For such a heavy mobile phone dependence, the most uncomfortable days of the year are the three days of the college entrance examination. In the short three days of the college entrance examination, in addition to the uninterrupted news reports and the unprovoked crowding when passing by the test center school, the most impressive thing is the poor mobile phone signal due to the use of signal jammers during the test. What is the sacred signal jammer of the mobile phone signal jammer? Today we will trace the ins and outs of this artifact.
When the signal jammer appeared in the first place, everyone was very happy. In the beginning, the signal jammer was not actually set up for the exam scene. The initial application of the signal jammer is actually a prison. The prison needs physical and information isolation. In order to ensure the security and privacy of information in the high-wall compound of the prison, it is necessary for the prison to isolate the communication signals between the prison and the prison. This is the original intention of the signal blocker. When the signal jammer was first invented, the whole world only developed into the 2G era. At that time, although there were three domestic operators, the mobile phones used the second-generation network communication technology. The communication frequency of mobile phones used by manufacturers of different standards is not bad.
The call between the mobile phone and the mobile phone is forwarded through the base station. The mobile phone's ability to make and receive calls mainly depends on the support of the communication base station. After the mobile phone is turned on, it will actively connect to the communication base station closest to him, and the communication base station will command it when making and receiving calls. In fact, it is all communication with the communication base station. So if the prison wants to interrupt the communication between prisoners and the outside world, what needs to be done? The noise generated by the jammer covers the signal jammer of the mobile phone. The noise is so great that the base station cannot hear the mobile phone. The answer is very simple. It is only necessary to make noise from a machine with the same frequency as the mobile phone, so that when the base station tries to connect to the mobile phone time. You will find that the signal coming from the mobile phone is messy and unrecognizable, so you will refuse to communicate with the mobile phone. Based on this principle, the signal jammer was first developed and everyone was happy. The prison only needs to be equipped with a few jammers that can emit such noise to shield the mobile phone communication within the entire prison. With the need to shield the signal more and more scenes. Signal jammers that were originally designed to be used in prisons have gradually entered normal commercial scenarios, such as important meetings and exams.
Technology is advancing by leaps and bounds, and signal jammers are catching up with the development of communication technology in the 2G era. Signal jammers can function perfectly. At that time, most operators used the same frequency band and the frequency was relatively fixed, which made it relatively easy to interfere with. After the addition of 3G and 4G, the diversification of signal frequency bands follows the rapid development of communication technology. 3G and 4G communications were quickly applied to actual scenarios. At this time, the signal jammer encountered a dilemma, that is, the signal interference originally designed for 2G, because of the frequency, it cannot cover the 3G and 4G signals. This also renders the shield ineffective. In this case, the development of communication technology has begun to force the simultaneous development of shielding technology. In order to be able to interfere with 3G and 4G signals, the jammer quickly evolved a special interference function for 3G and 4G frequency bands. Then there is a problem that 2G, 3G and 4G all need to be shielded, so how about? How about shielding these three frequency bands at the same time and space? The eight-antenna jammer can shield 2G/3G/4G at the same time. The simple answer is that the interference bands corresponding to the three signals are repeatedly played in a cyclic manner. The interference bands cover three bands at one time, and the interval of this cycle is so small that the mobile phone simply There is no chance to speak but to sit down.
There are also Bluetooth and Wi-Fi, neither of which can be covered by 2G, 3G and 4G. Can you breathe a sigh of relief at this time? The answer is no, because there are two methods, Bluetooth and WiFi, which are not blocked. Many people don't understand the difference between the three methods of Bluetooth, Wi-Fi and mobile data. They all seem to be wireless communication technologies. In fact, the difference between the three of them lies mainly in the frequency band. In mobile communication technology, 2G mainly works in the 900-1700MHz frequency band, 3G works in the 1900-2100MHz frequency band, and 4G works in the 2300-2500MHz frequency band. Bluetooth and WiFi work at 2.4GHz. The full-featured jammer can already be handheld. That is to say, the aforementioned jammers that can shield 2G, 3G and 4G cannot cover the Bluetooth and WiFi frequency bands. So the jammer has evolved again. Add 2.4G to the range of interference to achieve interference and coverage of Wi-Fi and Bluetooth. So far several wireless communication methods commonly used in human society. All are completely covered. In the foreseeable frequency band, the signal jammer can better complete the task.
Signal reconnaissance and location, take the initiative to lock the source, if things are said to be perfect now. Is it true? Even if 2G, 3G, and 4G have been perfectly covered, as well as Bluetooth and WiFi, bone conduction and invisible headphones are also shielded. However, there are still newcomers who want to be able to crack the signal jammer, and the method they use is a communication method with a custom frequency band. The walkie-talkie has become the only possibility. The custom frequency band means to jump out of the mobile phone communication and Wi-Fi, Bluetooth and other frequency bands, and find a custom segment outside the frequency band covered by the jammer. In this case, it is bound to be developed for this purpose. Hardware equipment. Including signal generator and signal receiver.
According to the purpose of use, it is generally necessary to consider various factors such as signal attenuation and refraction. At present, some technologies on the market are mainly concentrated in the frequency band that can be received by the walkie-talkie. Some people with ulterior motives have also developed a transmission system that can break through the flat signal jammer on the basis of the walkie-talkie frequency band. Whether it is cheating on an exam or other illegal purposes such as eavesdropping, it is the target of such a communication system. In this scenario, the signal jammer cannot play a corresponding role. UAVs are used to detect and locate signal sources, but we are not helpless. The best way to deal with this scenario is actually signal detection and location, proactively attacking the signal source of a specific frequency band and arresting suspects. Therefore, during the normal college entrance examination, all the radio waves near the college entrance examination hall are actually recorded. Once there is an unrecorded signal, this radio wave will be quickly locked by the active detection system. Arrested by police officers. Multi-point positioning can determine the location of the signal source.