Category: NEWS

In the examination room of many large-scale examinations, in order to prevent students taking the examination from carrying their mobile phones without permission, secretly using mobile phones to contact the outside world during the examination and cheating in the examination, the installation and use of mobile phone signal jammers in the examination room is the most commonly used technical protection means . However, with the progress of the times, the peripheral electronic products that match mobile phones have flourished in recent years, such as smart watches or electronic bracelets, etc. Some smart watches can even be completely separated from the mobile phone, and can communicate with the outside world and communicate with the outside world by themselves. For data transmission, the question arises: can the mobile phone signal jammers commonly used in examination rooms block smart watches?

If you carefully understand the functions and technical parameters of smart watches, you can know that no matter what the appearance of these smart watches is, or there are more or less differences in functions, there will be no obvious difference in their basic communication modules, or It uses the WIFI module to bind with the mobile phone to complete the communication, or it has a built-in SIM card, which is equivalent to a simplified version of the mobile phone. After this analysis, the questions raised above are easy to answer: since the mobile phone signal jammer in the examination room can completely shield all mobile phones, the smart watch is almost equivalent to a simplified small mobile phone, so the mobile phone signal jammer in the examination room Smart watches can also be blocked.

Some students may be lucky enough to think that electronic products such as smart watches or electronic bracelets can be brought into the examination room. As everyone knows, in any formal examination, not only the mobile phone signal jammer in the examination room will directly block and block the signal, even such electronic products When the product enters the examination room, the invigilator will fail to pass the inspection with a metal detector.

We often encounter individual users who call us for consultation, and the consultation questions will be very abrupt, expressing their willingness to buy high-power mobile phone signal jammers directly. Hemming and hawing, unwilling to answer questions directly or accurately, we usually directly reject the purchase consultation of such individual users, and are unwilling to provide quotation information for equipment. Why don’t we sell high-power mobile phone signal jammers to individual users? Woolen cloth?

There are two main reasons for this: The first reason is that these individual users have unclear intentions to purchase high-power mobile phone signal jammers, and they are unwilling to explain clearly the usage scenarios, and even deliberately conceal some information. This will inevitably make people suspicious, worrying that their purpose of using high-power mobile phone signal jammers is not pure. At worst, it may even be engaged in some illegal activities with the help of high-power shielding equipment. You should know that according to the regulations of the national radio management department, under normal circumstances, high-power mobile phone signal jammers can only be put into use by some special management units to ensure communication security or for safety protection purposes. These units are using When using this type of equipment, we will pay more attention to the reasonable and compliant use, and will not turn on high-power mobile phone signal jammers rashly or at will. However, if it is an individual user who purchases and owns it, how can he restrict and regulate his personal use? Obviously, this problem is basically insoluble.

The second reason is that high-power mobile phone signal jammers are expensive, large in size, and consume a lot of power. Even if some individual users pretend to be corporate users to come to consult, they will often be persuaded by the price factor. The price of a conventional high-power mobile phone signal jammer is tens of thousands, or even hundreds of thousands. Such a high price, as an individual user, is usually unaffordable. Furthermore, individual users may have impure motives for using high-power mobile phone signal jammers, and consultation and purchase are often just a whim. Once they know the necessary parameters such as the size, weight and power consumption of the device, they will basically give up completely. The idea of buying a high power cell phone signal jammer is gone.

Some customers have asked us: In the process of performing the task of fleet safety protection, what is the interference effect of the vehicle-mounted frequency jammer in the driving state? Will the actual interference effect be affected by the speed of the vehicle?

The above-mentioned application scenarios are usually aimed at government leaders or important VIP customers. In the convoy where the vehicle is located, a vehicle-mounted frequency jammer is installed, starting from the departure of the convoy until reaching a safe destination. Here During the entire journey, regardless of whether you encounter parking, traffic jams, low-speed driving, high-speed driving, etc., always keep the vehicle-mounted frequency jammer working continuously to ensure that the entire fleet, especially the vehicles of important people, can be fully and reliably protected. Eliminate and prevent terrorists from detonating roadside bombs, car bombs, etc. by remote control.

When the vehicle-mounted frequency jammer is parked (stationary state) or driving at low speed, it is relatively easy to detect its interference effect on various signals, but if it is in the fleet and driving at high speed, its effective interference range will remain unchanged ?

According to our past experience in delivery acceptance and comprehensive testing, the interference effect of the vehicle-mounted frequency jammer at high speed (vehicle speed ≥ 100Km/h) is slightly lower than the test results at rest, and the decline is about 10%~20%, the overall impact is not large.

However, customers also need to be reminded that: for different signal types, the interference distance and effect of the vehicle-mounted frequency jammer will be affected by many factors. For example: For remote control or intercom signals, etc., the difference in the test results is not large when driving at low speed and high speed. For mobile phone signals of various standards, the difference is more obvious. This is mainly because the interference distance of the vehicle-mounted frequency jammer to the mobile phone signal is closely related to the distance from the mobile phone base station. When testing in a static state, the test results are relatively It is relatively stable. When driving at high speed, due to the continuous passing of the base station along the way, the mobile phone will also switch the base station signal intermittently due to the distance from the base station, resulting in the strength of the mobile phone signal always changing. Therefore, during the driving process of the vehicle-mounted frequency jammer, the interference distance to the mobile phone will always be in a dynamic state.

Conventional signal jammers use white noise broadband transmission and rely on power to suppress interference to achieve signal interference. With the rapid deployment of 5G base stations by various communication operators in recent years, the excessive density of base stations will cause customers to feel signal interference. The effective distance of jamming is shortened. So some customers proposed to increase the transmission power of the interference signal, and then the question arose: what is the interference effect after the power of the signal jammer is doubled? Can the interference distance be doubled?

The results are often regrettable. For example: in a certain practical application site, if the average transmission power of each output frequency band of a signal jammer is 2W, use a mobile phone to test the effective interference distance, assuming that the result of the field test is that the radius of the effective interference area is 10 m. If we replace it with a signal jammer with an average output power of 4W for testing, we will find that: first of all, its effective interference radius is almost impossible to double, that is, in this field environment, it is impossible to reach a radius of 20 meters. But at the same time, we can also find that compared with the original distance of 10 meters, after the transmission power is doubled, the effective interference distance will increase, but it will not be obvious, and it may be increased to about 12 or 13 meters. Even sometimes it feels like there is no change, and it remains at a position of about 10 meters. Why?

The reason is that in the field of radio frequency communication, the unit we usually use to convert the “W” that represents the radio frequency output power into a level value becomes “dBm”. Here I recommend an oral calculation formula for converting the transmit power value into a level value: every time the “W” of the power doubles, the level value will increase by 3dBm. Still use the previous example to illustrate: when the output power is 2W, the corresponding level value is 33dBm, when the power is doubled and 2W becomes 4W, the corresponding level value is 36dBm, when the power is doubled, When 4W becomes 8W, the corresponding level value is 39dBm.

If the signal jammer wants to achieve a completely stable jamming effect, it is usually required that the strength of the jamming signal emitted by it, that is, the level value, should be at least 5~8dBm higher than the strength of the base station signal. In the real environment, due to the large number of base stations, there are many differences in the location and direction of distribution, and considering the influence of other factors, in the test site of the signal jammer, when we go to detect the signal strength of the base station, it is actually not fixed or not. Instead, it is in a state of beating and changing all the time. The signal of the base station is strong and sometimes weak, and the difference in beating may even reach more than 5dBm. Because of this, even if the signal jammer increases the transmission power by one part, that is, the level value increases by 3dBm, but the increase range may still be within the range of the base station signal’s change and jump, so in the end it will be It is difficult to see a significant increase in the distance of signal interference.

We often encounter customers who ask us: Can your product block the camera? I need to buy a set of wireless signal jammers to block surveillance cameras. When encountering such a question, we really can’t give an answer right away. We have to ask the customer first: the target object you need to shield, that is, the surveillance camera, how does it transmit signals with the main control terminal of the surveillance system? ? That is to find out whether the signal is transmitted through the video cable or the wireless signal transmission through the wireless communication technology between the two. So the customer’s question came out: Can the wireless signal jammer shield the monitoring transmitted through the cable?

The answer to this question is very clear: wireless signal jammers can only be used to shield wireless signals, and the transmission of wired cables does not work. Only surveillance cameras that use wireless transmission of audio and video signals can be effectively shielded.

The vast majority of surveillance cameras using wireless communication technology use WiFi2.4G, WiFi5.8G or 4G and 5G data communication services of mobile phone SIM cards, and a small part of them use unconventional frequencies such as 433MHz and 1.2G. Wireless data transmission, but no matter which frequency or frequency band is used, the wireless signal jammer can be equipped with a targeted shielding module to achieve effective shielding of these wireless communication frequency bands. This is absolutely free from technical hurdles and difficulties.

However, if the surveillance camera is connected by cables, especially these cables are often wrapped with shielding materials, then the wireless signal jammer cannot play a shielding role against such wired cables. But there is one exception: if the wireless signal jammer is placed close to the surveillance camera, or the antenna of the wireless signal jammer is next to these communication cables, sometimes even the audio or video signal transmitted through the cable will be observed. , there will still be some cases of interference, but the performance of this interference is not uniform and stable, for example, the picture shakes, blurs or flashes, audio pitch changes, and so on. In extreme cases, the image may disappear completely and the audio cannot be distinguished, etc. This mainly depends on the power of the wireless signal jammer and the distance between equipment and wires. And this kind of interference phenomenon cannot be called complete shielding, it belongs to the category of electromagnetic interference more.

There are many places where mobile phone signal jammers are used, such as school examination rooms, dormitories, meeting rooms of government agencies or confidential units, production lines and warehouses of factories and enterprises, and public security special police anti-terrorism, explosives and other places. Unfamiliar places, such as ships, will also require the installation and use of mobile phone signal jammers. Recently, when some customers consulted us and learned about applications in this area, we also specially shared some information about mobile phone signal jammers. What are the precautions for installation on ships.

If you plan to install a mobile phone signal jammer on a ship, you must first clarify a question: Is the target mobile phone inside the ship or within a certain range around the ship? If it is only aimed at the target mobile phone inside the hull, then relatively speaking, the implementation of the project is much easier, almost just using a conventional low-power mobile phone signal jammer. Just need to pay attention to waterproof, moisture-proof and ventilation when installing inside.

If it is aimed at the target mobile phone outside the hull and requires a certain coverage area, several considerations must be taken into account at the same time. This should at least include: a high-power mobile phone signal jammer must be selected, and a mobile phone signal jammer must be selected for the equipment host. A suitable installation location is required. The host of the device must also have functions such as waterproof, anti-salinization, and anti-corrosion. Where can the antenna of the device be installed to obtain the best coverage effect? When installing the antenna of the mobile phone signal jammer above the hull, we also recommend installing a special glass fiber reinforced plastic protective cover to protect several antennas. In addition, it is also necessary to focus on lightning protection and lightning protection measures around the antenna.

If the mobile phone signal jammer needs to be installed on a large ship, it may be necessary to consider installing it on the front and rear sections of the hull separately, so as to achieve the effect of comprehensive coverage.

Finally, there is another item to pay attention to: whether the ship goes to sea or visits other countries, if it often travels across seas and countries, then when choosing a mobile phone signal jammer, you must plan the configuration of the mobile phone frequency band in advance. Because there will be some differences in the frequency band parameters of each country.

The annual college entrance examination and high school entrance examination are coming soon, and the construction and preparation of standardized examination rooms are in progress. It is almost a must to install signal jammers in each examination room, so the education authorities or school leaders are choosing signal shielding equipment. When testing, the corresponding technical indicators and functional requirements will be put forward, so the question arises: Does the signal jammer in the examination room need to have many auxiliary functions? Are there more functions to better meet actual needs?

The so-called test room signal jammer is not just to shield mobile phone signals. It is actually a general name. The types of shielded signals it emits usually include Wi-Fi signals, Bluetooth signals and wireless data transmission , walkie-talkie communication, remote control cheating tools, etc. To evaluate whether the signal jammer in the examination room is good or bad, the first criterion is: whether it achieves effective shielding effect. The second basis for judging is: the distance or range where various signals are effectively shielded. When these two key technical indicators are met, other auxiliary functions will be assessed.

Nowadays, there are many manufacturers that can produce signal jammers for examination rooms, and each manufacturer has developed and launched many auxiliary functions around the products, such as:

1) Based on the Internet networking protocol, a large number of test room signal jammers are intelligently networked to realize remote intelligent control and management functions;

2) Turning on or off any frequency band in the shielding device can also realize the function of adjusting the transmission power;

3) Display the working status of the device through the LED indicator light or LCD screen;

The above is just a list of some representative auxiliary functions, not all of them. So in the actual use process, do customers have to require all these functions? In fact, not necessarily. We believe that these functions are only auxiliary after all. For the signal jammer in the examination room, these functions only play a role in strengthening intelligent management, and have no effect on the final signal shielding effect. Or to put it more bluntly: these auxiliary functions are icing on the cake.

In recent years, anyone who cares about international politics will know about the topic of “chip war”. The United States, which claims to be the world’s number one hegemon, began to attack my country’s semiconductor industry a few years ago in order to limit the rapid development of our country. The chip industry has carried out all-round restrictions and suppression. Over the past few years, many industries have also slammed the United States in the “chip war”. Now the question is, in the field of signal shielding, will the “chip war” affect the price of mobile phone signal jammers?

First of all, the “chip war” mainly refers to the strict blockade and control imposed by the United States and some European countries on chips with a process below 14 nanometers. The most affected and most representative is Huawei’s 5G mobile phone business. However, in the field of mobile phone signal shielding, since most of our signal shielding products use domestic chips, and the chip process standards used are not up to the 14nm level, so we can see the more gratifying results: After several years of “chip wars” until now, the price of our jammers has not fluctuated significantly, that is to say, the “chip wars” have hardly affected the price of mobile phone signal jammers.

Many years ago, we saw the steady development of our own domestic chips. When we were doing new product development and design, whenever there were domestic chips to choose from, we always took domestic devices as the first choice. We bring at least two benefits: First, the price of domestic chips will have an obvious price advantage compared to the price of imported devices, which will help control the price and cost of jammers. Another advantage is that it will not be controlled by others, and the purchase channels of key chips or electronic components will not be affected by changes in the international relations environment.

In recent years, the police department has begun to deploy communication jamming vehicles one after another in order to provide security protection or deal with emergencies. The protective barrier of wireless communication signals is used to prevent possible sudden terrorist attacks, or malicious events such as wireless communication, remote control, and drone approaching harassment. Among them, mobile phone users of unknown origin in the protection area are also one of the key protection targets, but the problem arises: the communication interference system on the vehicle already has the full-band wireless communication interference function, Of course, this includes the interference frequency band for mobile phone signals. So, is it appropriate to install a mobile phone signal control system on the communication interference vehicle?

What is “Mobile Phone Signal Control System”? This is different from the mobile phone signal jamming system installed on the communication jamming vehicle. The conventional mobile phone signal jamming system applies a high-power jamming signal on all mobile phone signal frequency bands, and suppresses all mobile phone signals within a certain range by power suppression. Cell phone signals are suppressed and interfered. The effect of this signal interference is indiscriminate and non-targeted for mobile phone users, and will not identify and distinguish specific mobile phone users. However, the mobile phone signal control system is not like this. Its working principle is somewhat similar to a mobile phone base station, and it can communicate with surrounding mobile phone users to a certain extent. Moreover, the identity codes of mobile phone users can be identified, and at the same time, the identity of these mobile phone users can be blacklisted or whitelisted. When a mobile phone user is identified as a blacklist, the mobile phone signal control system can lock it and prevent it from being used normally.

From this point of view, the functions of the mobile phone signal management and control system seem to be very suitable for the needs of some customers, but is it appropriate to install the mobile phone signal management and control system on the communication interference vehicle at the same time? Unfortunately, this application solution is not the optimal solution. The reason is that the communication jamming vehicle has already installed full-band mobile phone signal jamming modules. When these jamming modules are all turned on, they will continue to emit jamming signals. . The mobile phone signal control system is based on its own working principle. It needs to intermittently scan and receive the signals of the mobile phone base stations in the surrounding environment. In the process of receiving the base station signals, there are strong Interference signals in the mobile phone frequency band will directly prevent it from working properly.

In addition, when the mobile phone signal control system is installed on the communication jamming vehicle, even if there is no influence caused by the simultaneous operation of the mobile phone signal jamming system, there is still a problem of applicability in the use scene: when the communication jamming vehicle is driving at high speed, this set The mobile phone signal control system will not be able to enter the normal working state due to the rapid switching of the base station on the way.

It has been several years since we entered the 5G era. 5G jammers are also closely following the development of 5G communication. However, wherever there is a need to restrict the use of mobile phones, we will follow up in time and upgrade the original old-type mobile phone signal shielding equipment. . However, during this process, we will receive feedback from a small number of customers, saying that the effect of signal shielding has been reduced, especially for the signal of 5G mobile phones, and the effective shielding distance has been significantly shortened, so the problem arises. What should I do if the 5G jammer‘s shielding effect on 5G signals is not good?

Since the development of mobile phones from 4G to 5G, due to the need for higher data transmission rates, various communication operators have launched new 0.7 GHz (China Radio and Television), 2.6 GHz (China Mobile), 3.6 GHz (China Unicom) according to the country’s division of mobile phone frequency bands. , China Telecom) and 4.9GHz (China Mobile + China Radio and Television) and other high-frequency frequency bands, these newly launched 5G mobile phone frequency bands, in addition to higher frequencies, have a more obvious feature that their frequency bandwidth is relatively large, each operator The commercial capital has almost obtained a frequency bandwidth of at least 100MHz, which will lead to a consequence: if 5G jammers need to achieve effective shielding against 5G signals, they must ensure that sufficient power is applied to each 5G frequency band.

Before the advent of 5G, mobile phone jammers in the past usually only need to install 6-8 signal shielding modules, and the frequency bandwidth of each shielding module will not reach 100MHz, generally around 20~60MHz, but in 5G mobile phone jamming When the device starts to be mass-produced, each signal shielding module must cover a frequency bandwidth of at least 100MHz, and these are all newly added frequency bands, so that the production of a standard 5G jammer requires at least 10~12 signal shielding modules. module.

As a manufacturer, in order to meet the functional requirements of competitors and at the same time ensure the cost control and price competitiveness of 5G jammers, they will not rashly adopt the method of adding 5G signal shielding modules to improve the effect of signal shielding. This is why some customers reported that the shielding effect of 5G signals is not ideal.

What is the solution to this problem? In fact, it is relatively simple, that is, to get rid of the constraint of controlling production costs, to divide the shielding module in the 5G jammer, especially for the 5G signal shielding frequency band, more reasonably, to split the broadband into narrowband, and to increase the shielding module. quantity.

Due to the relatively small size of the portable frequency jammer, usually in the form of a trolley case or a backpack, it has strong application characteristics of portability and quick transfer, so it has been favored by many military or special police departments, but recently these In the past few years, we often see that the technical specifications of some procurement projects mention that the total RF transmission power of a complete set of portable frequency interference cannot be greater than 500W, but at the same time, its effective interference radius is required to be greater than 100 meters. Is this requirement reasonable? ? Does the portable frequency jammer with the total transmission power controlled within 500W really have such a good effect?

The frequency jammers we are familiar with basically use the interference signal to act on the target frequency band, and rely on the way of wide-band power suppression to achieve the interference effect. Nowadays, a full-standard frequency jammer needs at least 10-12 interference frequency bands only for mobile phone signals. If it needs to include remote control, walkie-talkie, GPS navigation and positioning, UAV image transmission, flight control, etc. and other interference frequency bands, then the total number of interference frequency bands will reach at least 18 or more. Through calculation, it can be seen that assuming that the upper limit of the total RF power of the interference signal is limited to 500W, then the average power on these interference frequency bands is only 20-30W. According to such power intensity, it is actually difficult to achieve an effective interference radius greater than 100 m.

If you want to achieve an effective interference radius of 100 meters, this will require some necessary test environments. For example: when testing the interference distance of mobile phones, it will be required that the base stations around the test site should not be too close, and the distance between the base stations should be as close as possible. reach more than 1 km. But in a real scene, it is difficult to find an environment where there are no base stations within a radius of 1 kilometer. In almost the vast majority of cases, if a location is randomly selected, there must be a mobile phone base station within a few hundred meters around it, and the number of base stations is very likely to be not a single one, but multiple ones exist at the same time, but each base station There will be a difference between far and near.

In most real application scenarios, to improve the interference effect of the portable frequency jammer, that is, to expand the interference radius, there are not many methods that can be adopted. The simplest and most effective method is to increase the transmission power of each interference module, but doing so As a result, it is bound to bring the total power to exceed the limit of 500W?

The final conclusion is: the current mainstream portable frequency jammer, its transmission power and number of frequency bands are generally not too high, it needs to be comprehensively evaluated with the appearance size, weight, power supply battery capacity, power consumption, etc. Appropriate trade-offs.

It has been several years since we entered the 5G era. Customers who installed a mobile phone jammer system a few years ago are beginning to face a problem: Should we directly buy a new type of device with 5G shielding function? Or upgrade on the basis of the original mobile phone jammer system? How to choose these two options depends on the customer’s investment budget for the project. Relatively speaking, directly purchasing brand-new shielding equipment will definitely pay a greater purchase cost, while adding a 5G function module to the original old equipment will save money. Then, the question arises: which frequency bands should be added when the mobile phone jammer system is upgraded to 5G?

The previous shielding equipment without 5G shielding function is usually equipped with 6-8 shielding modules, and the frequency band will include at least 800MHz, 900 MHz, 1800/1900 MHz, 2000/2100 MHz, 2300 MHz, 2600 MHz, etc. The mobile phone jammer system only needs to completely cover the above-mentioned frequency bands with the shielding signal, and then it can completely shield the 2G, 3G, and 4G signals of mobile phones. So which frequency bands are included in the latest 5G signal frequency bands? In fact, in different countries, the frequency division standards for 5G frequency bands are different. Taking mainland China as an example, the communication frequency bands allocated to 5G in our country are: 700 MHz, 2600 MHz, 3400 MHz, 3500 MHz, 4800 MHz and so on. Among them, the frequency band of 2600 MHz is expanded on the basis of the original 4G frequency band, from 2555-2655 MHz to 2515-2675 MHz.

When the mobile phone jammer system is upgraded to 5G, it is necessary to supplement these 5G frequency bands mentioned above. Of course, in the process of actual application, it is not really necessary to increase each frequency band accordingly, such as the frequency band of 4800 MHz. Since this frequency band has very few application scenarios in reality, only a few occasions will use this frequency band. The frequency band is used for private network communication. Therefore, when upgrading the mobile phone signal shield to 5G, the 4800 MHz frequency band can be directly abandoned and increased.

Based on the above analysis, if an old mobile phone jammer system is to be upgraded to support 5G standard, the newly added signal shielding module should focus on the following frequency bands: 700 MHz module, 2600 MHz module, 3400 MHz module and 3500 MHz module Of course, if the customer has a spectrum analyzer or a mobile phone test tool, he can check the mobile phone frequency bands in use in advance, and can determine which frequency bands need to be added according to the final test results.