Author: 897918909@qq.com

After the high-power wireless jammer is modified and assembled in the vehicle, it becomes a set of vehicle-mounted special equipment that can be quickly transferred, deployed and used with the vehicle as the transport carrier. Customers who have used it know that: the device host of the wireless jammer is installed at the rear of the vehicle, the transmitting antenna is installed on the top of the vehicle, and near the driver’s seat, a control handle with a cable connection or ‘s controller. So some customers asked this question: Can the car wireless jammer realize long-distance wireless remote control?

The customer has such questions and thoughts. The original intention is that the operator of the in-vehicle jamming device does not need to be in the vehicle all the time when it is necessary to turn on, off or set the wireless jammer. This is because the controller of the device is connected through the control cable. Connects to the device host and has a limited length. What the operator wants is to remotely control the jamming device on the vehicle in a position far away from the vehicle through a remote control-like manner.

The unfortunate result is that the existing commonly used remote control or remote control methods cannot currently meet the needs of customers. The reason is actually very simple: the commonly used remote control methods now transmit control commands by wireless communication. Whether it is the receiving end or the transmitting end, data communication will be carried out at a relatively fixed wireless frequency or frequency band. These frequencies or Frequency bands, the most common ones are: 433MHz, 2.4G and 5.8G, then the embarrassing reality emerges: what does our car wireless jammer do? Its function is to interfere with wireless signals, which of course includes the most basic and common frequencies and frequency bands used for remote control signal transmission.

If the technology of wireless remote control is forcibly used as the control method of the in-vehicle wireless jammer, the following results will occur: the operator uses the remote control at a long distance from the in-vehicle jamming device, and there is no problem in remotely turning on the device, but as long as it is The jamming device is turned on and working normally, because the emitted jamming signal will immediately interfere with the signal of the remote control frequency band. No matter how the operator uses the remote control next, he will no longer be able to form effective communication with the remote control receiver of the wireless jammer. Naturally, remote shutdown cannot be realized, and other functions or parameters of the interference device cannot be set and modified.

Due to the need to limit the use of mobile phones in many occasions, installing frequency jammers has become the most effective way to solve this problem. However, users like some schools, prisons, detention centers, etc., their needs for frequency jammers are large-scale, and they often need dozens or even hundreds of them. So how to control and manage the large number of shielding devices in a unified way promotes the synchronous development of the frequency jammer control system. Nowadays, several shielding devices with remote unified centralized management function can also be seen on the market. After comparing the product functions and support performance, the question arises. Why do the control systems of frequency jammers mostly adopt the transmission method of wired connection?

In the current control systems of common frequency jammers, the networking methods of multiple shielding devices are almost all connected by wired connection. The wired connection here refers to the conventional network cable networked with the TCP/IP protocol, or the 485 serial port. Multi-core cable for protocol networking. There is another way, which is in the form of power carrier, by means of the power line that supplies power to the frequency jammer, and also transmits the control system while supplying power. But no matter which of the above methods, their communication network is actually through wired connection. So some customers thought: Wired connection must require construction wiring, so is it possible to use relatively mature wireless networking technology to control several frequency jammers online?

Although the biggest advantage of wireless networking is that there is no need to arrange dedicated communication cables, the communication frequency band used in wireless networking is precisely the communication frequency band that needs to be shielded or interfered most during the use of our frequency jammers, such as 433MHz. And WiFi2.4G, 5.8G, etc., if the wireless connection method is used to realize the network of the frequency jammer control system, this will cause a very embarrassing result: when the administrator remotely turns on the frequency jammer through the software, it has not been shielded at this time. Signal, turning on the equipment in the system can be realized normally, but once the shielding device is turned on, the wireless communication signal will be interfered by the shielding signal, which will cause the management personnel to send and transmit the next control command. , the signal cannot be reached or the transmission distance is severely shortened. This also makes the entire frequency jammer control system function unstable.

Because of the factors that cause unstable signal transmission analyzed above, most of the control systems used for frequency jammers can only use wired connection and network transmission.

After some units have installed and used the phone jammers produced by our company, they will receive consultation calls from the staff of the unit within a certain period of time, wanting to know if there is any way to crack the phone jammers. Obviously, these people are the After the mobile phone is blocked by the signal, I want to use other methods to relieve or bypass the influence of the phone jammer. So, as a manufacturer, how should we answer the reply?

In fact, the final answer will definitely disappoint these people. Although the phone jammer installed in the unit is called “signal shielding”, it is actually “signal interference”, which is to interfere with all mobile phone signal frequency bands. Signal, and the interference mode is relatively a simple and rude method of power suppression. To put it bluntly, it is to see whose signal is stronger and whose power is greater. If the cell phone jamming signal prevails, the cell phone signal will be completely blocked. If the signal from the mobile phone base station prevails, the performance on the mobile phone is that the signal is unstable, and the effective shielding distance is correspondingly shortened.

The interference signal applied to the mobile phone signal frequency band is a chaotic and disordered white noise signal. Because of this, there is no possibility of cracking. Moreover, once this interference signal is transmitted, it cannot be counter-interfered or reversely suppressed by other devices.

The installation of phone jammers in the unit must be due to the need to restrict the use of mobile phones, otherwise such devices will not be installed for no reason. If it is because this affects the use of mobile phones, we can only advise these individuals to try their best to perform their job duties in accordance with the rules and regulations of the unit when using mobile phones, rather than trying to find other ways or methods to crack the role of phone jammers .

Every few months before the college entrance examination and high school entrance examination, many school customers ask us about test room radio jammers. In the process of product consultation and understanding, there is a problem that customers often mention. This problem is: just want to buy a Two high-power examination room radio jammers can cover the shielded signal to all examination rooms in the school. Customers think that it will be easy to install and operate due to the small number of devices, so is this really the case?

To use a common saying: ideals are plump, reality is skinny! It is true that the high-power signal shielding device has a large transmission power and a large signal coverage, but what needs to be known is that the high-power signal shielding device is actually not suitable for the examination room environment of the school. First: its main application scenario refers to the outdoor environment. Second: Its coverage is large, which also means that the transmission distance is large in a visual environment (without obstacles). If the shielded signal has obvious obstacles in the transmission path, such as walls, buildings, etc., the signal will be attenuated. The degree will be very large, and it will not be possible to achieve a wide range of signal coverage. The school’s examination room is obviously composed of various floors and classrooms, and there are partitions between them. This is not a transparent, visible environment.

Furthermore, if the test room radio jammer is selected as a high-power model, it cannot be simply considered that its installation and operation are very easy and convenient. In fact, the installation location of the high-power radio jammer must not be selected in the building or on the roof, because it is necessary to avoid the blocking and attenuation of the shielded signal by the walls and floors of the building. In the actual application process, the high-power radio jammer needs to be installed at a suitable distance in front of or behind the building, and usually it is not simply to place the shielding device directly on the ground, but the radio jammer should be installed. The antenna of the device should be erected to a certain height, such as at least 2-3 floors. In addition, it is also necessary to consider that the equipment may encounter thunderstorms during the use process, so it is inevitable to consider the installation of lightning protection and waterproof protection measures for the shielding equipment.

Based on the above analysis and suggestions, we know that the school’s test room radio jammers are generally not recommended to use high-power models, and the most commonly used ones are low-power models, which can be directly installed in the test classrooms of each test room.

The widespread use of mobile phone jammers will cause certain interference to the base stations of communication operators. This is a reality that is generally recognized in the industry. If it is a low-power mobile phone jammer, due to its relatively small transmit power, it will interfere with signal transmission. The distance is limited, so in the case of a small number, the interference effect on the mobile phone base station can be tolerated. However, if some customer units purchase and use high-power mobile phone jammers, and their jamming modules still use the conventional white noise high-power suppression method, then the nearby communication base stations will be unbearable!

However, as a professional manufacturer of high-power mobile phone jammers for nearly 20 years, we have relevant technical means to ensure that our high-power shielding equipment does not interfere with the base station. The customer’s question is, how do we realize the mobile phone jammer that does not interfere with the base station?

In fact, it is not difficult to solve the problem of base station interference. Usually, the interference to the base station is mainly aimed at the interference of the uplink frequency band of the base station. In the past, the base station signal of the mobile phone was divided according to frequency, and the uplink frequency band and the downlink frequency band were generally specially divided, and the mobile phone jammer mainly interfered with the downlink frequency band of the base station. Unless the manufacturer of some inferior products cannot precisely adjust the interference signal within the range of the downlink frequency band, it will generally not interfere with the uplink frequency band of the base station. However, with the rise, promotion and popularization of the TDD standard for mobile phones, since the standard adopts the time division duplex working mode, that is, it is within a fixed frequency range and does not distinguish between uplink and downlink frequency bands. The bandwidth of the frequency band is divided by time, that is, the uplink signal is processed in one time period, and the downlink signal is processed in the next time period. It is precisely because of this mobile phone frequency band system that does not distinguish between uplink and downlink, when our mobile phone signal shielding device performs signal interference for this frequency band, the conventional continuous white noise interference method will inevitably produce signal interference in the uplink time period. .

Since the working mode of TDD is time division duplex, the solution is easy to implement, that is, to synchronize with the time slot of the base station for processing uplink and downlink signals through a synchronization module that receives signals from the base station. Once synchronized, let the mobile phone jammer’s interference signal only be transmitted during the time period when the base station processes the downlink data, which perfectly avoids the time period when the base station processes the uplink data. Therefore, it will no longer interfere with the communication base station.

There are many kinds of mobile phone jammers on the market today, and most of them are realized by means of broadband white noise power suppression. During its use, there are many types of shielding devices that more or less interfere with the surrounding mobile phone base stations. This kind of interference is mainly aimed at the interference of the uplink signal of the base station, and the method to solve this interference problem is actually not difficult. It only needs to add signal synchronization technology to the interference signals of some specific frequency bands. So, in which frequency bands does the mobile phone jammer need to add synchronization technology to avoid interfering with the base station?

The frequency band targeted by the synchronization technology mentioned here refers to the mobile phone frequency band using time division duplex, while the other frequency division duplex mode is used to strictly distinguish the range of the uplink frequency band and the downlink frequency band. We use the frequency band of GSM900. For example, the uplink frequency range of GSM900 is 885-915MHz. In this frequency range, only data transmission of uplink signals is performed. The downlink frequency range of GSM900 is 930-960MHz. In this frequency range, only data transmission of downlink signals is performed. These two frequency bands do not overlap with each other, and data communication goes its own way. Let’s take the time division duplex frequency band as an example, such as the TD-SCDMA frequency band, the frequency range is 2010-2025MHz, and the overall bandwidth is 15MHz, but because of the time division duplex technology, both uplink data and downlink data are in this 15MHz bandwidth. For transmission, it is only divided by time, that is, it is dedicated to uplink data in a period of time, and dedicated to downlink data in the next time period.

We use the upper synchronization technology in the mobile phone jammer, which is to synchronize the time division duplex frequency band, so that the signal shielding module for time division duplex only transmits the interference signal when the base station performs downlink signal data processing. On the contrary, when the base station When processing uplink data, the corresponding frequency band of the mobile phone jammer stops working.

We have sorted out and counted the frequency bands of time division duplex used by various operators at present. Now there are mainly 5 frequency bands using time division duplex technology, namely: China Mobile’s 1885-1925MHz, 2010-2025MHz and 2510-2690 These three frequency bands, as well as the 2300-2390MHz for indoor signal amplification and the 5G-NR frequency band of China Telecom and China Unicom, namely 3400-3600MHz.

Based on the above analysis, when we add signal synchronization technology to all the five frequency bands built in the mobile phone jammer, we can completely avoid interfering with the uplink signal of the mobile phone base station.

Some important military key departments or secret places have chosen our high-power UAV jamming system because of its wide coverage, and its effective defense radius against illegal intrusions can reach several kilometers. During the installation of the equipment, some customers asked us, what is the appropriate installation height for this high-power UAV jamming system? Is it better to install it as high as possible? Can it be installed directly on the roof of a building?

If the desired purpose is to maximize the jamming signal range of the anti-UAV, then the ideal result is to install the UAV jamming system as high as possible, or the higher the height of the transmitting antenna of the jamming system. The better, as long as the height of the antenna is high enough, the interference signal emitted by it will not be blocked by other obstacles when it is transmitted and covered around, resulting in signal attenuation, or reflection and demolition. The obstacles mentioned here will have different degrees of influence on the attenuation of the interference signal due to their different types and materials. Among them, the reinforced concrete structure of the building has the greatest attenuation of the interference signal. Therefore, when we suggest that the best installation height of the UAV jamming system is higher than all surrounding buildings, if conditions permit.

The installation height of the UAV jamming system is higher than that of all surrounding buildings. There are two installation methods to choose from. The first is to directly use the top floor of the highest building, and only need to install a few meters of poles on the roof. The installation is completed quickly. Another way is to first install a pole of sufficient height on the ground, similar to the style of a street light pole or a signal tower pole. The high-power UAV jamming system needs to be stably and reliably installed at the upper end of the vertical pole.

However, what we need to remind is that when using the pole installation method, the host and antenna of the UAV jamming system must be protected by reliable power supply grounding, equipment waterproofing, and antenna lightning protection. In addition, due to the large weight of the equipment itself, it must be stable when installing the equipment. If necessary, a crane or hoist should be configured on the installation site to ensure the smooth progress of the installation process.

As the control measures for the standardized use of drones by the higher authorities become more and more perfect, the commercial drones sold by regular drone manufacturers are strictly in accordance with the relevant regulations, and the drones sold are pre-set Some limiting parameters are set, for example, in some areas that are set as no-fly zones, the drone will not be able to take off, and in the main urban areas of some major cities, the flight height limit is demarcated, and the drones of regular manufacturers will not be able to take off. The flight will exceed the flight height limit again. However, after all, there will be some individuals or small groups who want to break through these restrictions for some special purposes, so some types of drones will be modified privately to get rid of the regulations and restrictions on the use of drones. How can the drone jamming equipment defend against these privately modified drones?

We need to analyze which aspects of privately modifying drones usually start from:

The first way is to modify or lift the restrictions on the built-in parameters of the drone, which requires professional technicians who understand the writing and modification of the built-in program of the drone. This method is more difficult. It is difficult for ordinary personnel to get started. If this is the only way to unlock the restrictions of drones, the drone jamming equipment hardly needs any adjustment, and can effectively strike or defend against such drones.

The second way is to modify or replace the drone’s flight control frequency band and image transmission frequency band. If you want to make such a modification, you need a corresponding hardware engineer to complete it. Usually, some communication modules with very common communication frequencies are purchased to replace the original data transmission components of the drone. It is also possible to purchase some communication modules with higher power and stronger anti-interference ability to enhance the unmanned aerial vehicle. the altitude and distance of the aircraft. For this type of modification, the drone jamming equipment must be adjusted accordingly. Our suggestion is to add jamming modules in multiple frequency bands. Since the other party hopes to maintain normal communication by adding communication modules of different frequencies, we will take into account all the wireless communication frequencies that the other party may use, and implement high-power interference on all these frequency bands.

Some customers may have questions. What if the drone is modified privately to use a communication frequency that is not commonly used at all? Can the drone jamming equipment still have the corresponding frequency jamming to hit it? In fact, there is basically no need to worry about this, because the communication components required for privately modifying the drone, especially some core radio frequency components, are not individuals who have the ability to define frequencies and produce at will, they can only be outsourced, and the market Such devices that can be purchased on the market are produced and supplied in accordance with the relevant frequency band division standards in the industry. So to sum up, no matter how the drone is modified privately, our drone jamming equipment can also be perfectly solved by adding the corresponding jamming module.

DJI’s DJI Mavic 3 (Yu 3) drone has been on the market for a while. Recently, a customer reported a problem when communicating with us: the previously purchased and installed drone jammer is not suitable for this new type of large-scale drone. Xinjiang’s DJI Mavic 3 (Yu 3) drone does not seem to have obvious interference effects, especially in driving away and forced landing. Compared with the performance of other drone models after interference, it feels that there will be a certain gap. The client wants to know why this is and what is a good solution?

First of all, we should know that every time DJI launches a new type of drone, its anti-jamming capability has been further optimized and upgraded. According to our detailed analysis and understanding, DJI’s new DJI Mavic 3 (Yu 3) drone, its remote control flight control and image transmission, uses the most commonly used 2.4G and 5.8G frequency bands, but in The anti-interference ability of frequency hopping has been better strengthened. Compared with the previous models, the more special change is the addition of the Beidou positioning module in its navigation and positioning module. Understand this, then the reason for the weakened function of the drone jammer in driving away and forced landing can be roughly analyzed.

The drone jammers produced and supplied in the past have built-in GPS navigation and positioning jamming modules, and the frequency coverage may not have enough frequency bandwidth reserved, resulting in the jamming signal not fully acting on the frequency of Beidou navigation. From the perspective of frequency division standards, the frequency range of Beidou Navigation has exactly two frequency bands, which are in the starting and ending areas of the GPS1.5G frequency band. The solution to this problem is not difficult and complicated. Our suggestion is to return the original drone jammer to the factory to re-adjust the transmission frequency of the GPS frequency band.

In the face of the continuous introduction of various new models of drones, drone jammers cannot remain conservative all the time. They should also keep pace with the times and keep updating and progressing at any time!

As an important part of the signal jammer, the antenna is indispensable, but according to various usage scenarios or application requirements, customers often make specific requirements on whether to choose an omnidirectional antenna or a directional antenna. Some customers even directly proposed to us that they need to equip the signal jammer with one set of omnidirectional antenna and one set of directional antenna at the same time, and put forward the expectation: hope to realize the switch between omnidirectional and directional at any time? Can this be done?

As a manufacturer of signal jammers, we usually configure omnidirectional antennas for low-power models and directional antennas for high-power models. Of course, according to customer requirements, high-power signal jammers are equipped with omnidirectional antennas and directional antennas at the same time. It is also completely possible. Customers can decide whether to use omnidirectional or directional antennas according to the needs of the mission. However, the functional requirement of switching between omnidirectional antennas and directional antennas at any time may not be as simple as the customer expects.

The original intention of the customer is to achieve such an effect: the omnidirectional antenna and the directional antenna are ready at the same time and connected to the equipment normally, and the directional and omnidirectional switching can be completed only by a switch. It’s like an AC/DC toggle switch. However, in the field of wireless radio frequency signal transmission, such an expectation cannot be simply analogized. The interference signal output from the radio frequency port of the signal jammer is transmitted to the antenna through a dedicated radio frequency cable or radio frequency connector. At present, although there are some RF switches, they are generally used in products that transmit low-power signals. For high-power signal jammers like ours, there is no suitable RF switch that can match each other to achieve such functional requirements.

The disadvantage of adding a radio frequency switch is that the signal jammer usually has more than ten radio frequency bands, and the number of antennas corresponds to one of them. One frequency band corresponds one to one, and it is difficult for a large number of switches to operate at the same time. Moreover, due to the increase of RF adapters, the attenuation during signal transmission is undoubtedly increased for no reason.

To sum up the above, under the existing technical conditions, it is not convenient for the signal jammer to realize the switch between omnidirectional and directional at any time. It is necessary for customers to evaluate and analyze the use site in advance, and make a choice about what kind of antenna to use.

As one of the most important components of the signal jammer, the antenna is the most common for every customer who comes into contact with this product. The most common one is the cylindrical omnidirectional antenna. When customers have the opportunity to see different models, After using various types of signal jammers for different purposes, you will find that in addition to the different appearances of the jamming devices, the antennas configured are also different. In particular, there are multiple antennas configured by some interfering devices, and their lengths are exactly the same, but there are multiple antennas configured by some devices, and their lengths are not exactly the same. What is going on?

First of all, let’s take a look at the structure of the omnidirectional antenna. The antenna of the signal jammer we usually see is actually only the shell of the antenna. The antenna shell is hollow in the middle, and the real performance of the antenna is in the shell. , Hidden in the antenna shell is the antenna core, which can be a radio frequency cable, or an antenna vibrator made of copper wire, copper sheet or other metal materials.

The length of the core of the antenna is related to its corresponding standing wave frequency. Different standing wave frequencies use different antenna core lengths. According to the characteristics of the relationship between frequency and wavelength, there is a basic rule: the higher the frequency, the shorter the core length of the antenna, on the contrary, the lower the frequency, the longer the core length of the antenna.

We sometimes see signal jammers that use the same length of antenna. In fact, these antennas use a uniform length of the antenna housing, which is done for aesthetics and uniformity. In fact, each of these antennas with the same length corresponds to a working frequency band. Therefore, if you only need to observe these antennas carefully, you will find that the tail ends of these antennas will have clear identification marks of frequency parameters. In practical applications, usually low-power signal jammers use omnidirectional antennas of the same length.

In high-power signal jammers, the configured omnidirectional antennas have relatively high requirements for technical indicators such as carrying power and standing wave ratio, and also to avoid wasting unnecessary antenna casing sleeves. It is no longer mandatory to make the length of the antenna exactly the same. It even sometimes appears on high-power signal jammers. Not only will the antenna lengths of each frequency band be inconsistent, but also the diameter of the omnidirectional antenna will be inconsistent.

Whenever the college entrance examination, middle school entrance examination or college English CET 4 and CET 6 test, the signal jammer in the examination room, as an important tool to maintain the fairness of the examination, ensure the stability of the examination room and prevent candidates from cheating, will work throughout the entire examination process. However, there are still a small number of people who, out of personal desires, try to avoid the protection measures of the examination room, and even resort to some extreme sabotage. So how can the signal jammer in the examination room prevent sabotage?

Usually in the process of various types of exams, when the competent unit of the exam uses the signal jammer in the exam room, there are two ways. The first is to use a desktop jamming device, which is distributed to the invigilator before the exam or distributed to each Exam classrooms will be collected after the exam is over. This method will bring some problems: the process of issuing and recycling signal jammers in the examination room is time-consuming and labor-intensive, and the installation and use are more casual. Some invigilators place the equipment directly on the podium, while others On a stool or on the ground, because the interference device must be powered on before it can be used, the AC power cord needs to be used to connect the device host to the power outlet, so this method is very irregular. There is also a very critical point: the process of frequently issuing and recycling signal jammers in the examination room will inevitably cause damage and damage to the equipment.

Another way is to use a wall-mounted test room signal jammer, which means that the jamming device is installed in the test classroom in advance, and only needs to be turned on when the test starts. This installation method is relatively standardized and safe, and since the installation height will be slightly higher than the upper edge of the blackboard, it is more effective to prevent human damage.

From the analysis of the methods of artificially destroying the signal jammer in the examination room, the most common methods of destruction are: unplug the antenna of the interference device, unplug the power cord of the interference device or the network cable of the network communication. In order to effectively prevent these damage methods, the current mainstream signal jammers in the examination room basically use the method of built-in antenna, that is, the device is installed in a closed shell as a whole, and the antenna can no longer be directly contacted from the outside. And the SMa-818B5 test room signal jammer designed by our Nanjing Bokang Electromechanical Technology Co., Ltd. specially designed for the test room environment has achieved the equipment’s switches, power lines, network communication lines, etc., all concentrated in a hidden installation box. , which further improves the level of protection against vandalism!