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In most cases, when installing and using a mobile phone signal jammer, it is required to shield the mobile phone signal and the WiFi signal at the same time. The WiFi signal here includes WiFi2.4G, Bluetooth, WiFi5.8G, etc. However, there will also be some occasions with special requirements.

Customers will request that the mobile phone cannot make calls or chat online, but at the same time retain the smooth transmission of WiFi signals. The reason why there is such a requirement to reserve WiFi signals separately is because there may be There are working equipment and instruments that must rely on WiFi signals for communication. Once the WiFi signals are shielded while shielding the mobile phone signal, the normal working status of these devices will be affected. So for such a situation, can our mobile phone signal jammer block the mobile phone signal without affecting the WiFi signal?

In fact, this problem is not difficult at all for our mobile phone signal jammer manufacturers. Customers only need to express to us clearly the usage scenarios and clear requirements before ordering the shielding equipment. No need to shield WiFi signals, then we will produce and assemble When using the mobile phone signal jammer, the shielding modules of the WiFi2.4G frequency band and WiFi5.8G frequency band are no longer selected for installation, so that the finished products produced in this way will undoubtedly not have shielding and interference effects on WiFi signals.

After deciding not to install WiFi2.4G and WiFi5.8G shielding modules, there will actually be two more modules inside the mobile phone signal jammer. Customers can then have two options: the first The choice is to keep the status quo, and only install shielding modules that are purely for mobile phones, so that the production cost of shielding equipment will be reduced, and manufacturers will also give certain price discounts accordingly. The second option is to use the two extra module installation positions and ask the manufacturer to give suggestions to split the individual frequency bands with particularly strong signals or large frequency coverage, so as to improve the shielding effect of the mobile phone frequency band.

Now the common radio frequency jammers for outdoor applications, the nominal interference frequency range is usually marked as 20MHz-6000MHz, some careful and familiar with some radio knowledge enthusiasts may find: the common operating frequency of FM radio (87.5 MHz-108MHz) is completely covered in this frequency band. It can be seen from this that within the effective radius of the interference, the FM radio will be affected by the interference signal and cannot be listened to normally. Then the question arises, is it necessary for the radio frequency jammer to interfere with the frequency band of the FM radio?

As we all know, FM radio is used to receive various programs from FM radio stations. The frequency bands that FM radio stations work in are completely open, and the frequencies are all between 87.5MHz and 108MHz. It is for public use and not encrypted. Any FM radio can be used to receive audio programs from FM stations. If the interference frequency band of the radio frequency jammer includes the working frequency of the FM radio, then it can interfere and affect the FM radio within a certain distance from it. However, it should be noted that due to the limited transmission power of the radio frequency jammer itself, the propagation distance of its interference signal is also limited, and it is usually not able to directly interfere with further FM stations.

All radio frequency jammers must interfere with all common wireless signals of 20MHz-6000MHz. The main purpose is to prevent criminals from engaging in some malicious sabotage activities through wireless remote control. From this perspective, in the real application process We will find that it is not common to use the wireless signal receiving and transmitting circuit of FM radio tone to modify or make it into a remote control device. Ability is also unreliable, so this method is extremely rare. Since this situation exists, is it necessary for the radio frequency jammer to interfere with the frequency band of the frequency counter radio?

Our conclusion is: in most scenarios, it is possible to avoid the working frequency band of the FM radio, and adjust the effective power of the jamming module to other working frequency points more intensively. If the jamming module of the low frequency band of the wireless frequency jammer has DDS digital frequency modulation function, so it is very convenient to quickly set the frequency band parameters through the software.

In the past ten years or so, it has become common for schools to purchase and install mobile phone jammer systems, but most schools only use them as anti-cheating safeguards during the examination process, and only in some of the more important types of examinations. It will only be used in high school, such as the annual high school entrance examination, college entrance examination, or the CET-4 and CET-6 of college English. It can be seen that the usage rate is actually relatively low, so here comes the problem. The mobile phone jammer system that the school has spent a lot of money and great efforts to build is not only used to prevent cheating in exams, but also has expanded applications in school teaching management. No? If so, what extensions can be included?

First of all, if the school selects the online version of the mobile phone jammer terminal with intelligent networking functions when selecting the initial product type and formulating the mobile phone jammer system project plan, the result is that the school can fully utilize the potential of such a mobile phone jammer system play out.

The online version of the mobile phone jammer system has obvious advantages over the stand-alone version of the mobile phone jammer. The stand-alone version has no networking function and cannot realize intelligent centralized control and management. If it is necessary to expand the functional application, the solution is to first complete the networking work through the external networked controller.

Once the intelligent mobile phone jammer system completes the networking work, the school administrators can conduct centralized control and management on the remote main control software. The main control software can communicate with the school’s teaching management software platform. The easier-to-implement function is that it can be synchronized with the school’s ringing bell. For example, when the class bell rings, the mobile phone jammer system will be turned on simultaneously. The device system is then shut down synchronously, so that the work of the system can be run in line with humanization, and this system can be used to maintain classroom order and prevent students from secretly using mobile phones during class and not concentrating on learning.

The school can also be freely grouped according to each grade or each building, each floor, etc., and can group different areas in the school and conduct jammers in different areas. These can be done on the main control software of the mobile phone jammer system Edit and set.

If the school installs the mobile phone jammer system in the dormitory area of the students, then through the timing function of the main control software, the shielding system can be automatically turned on when the students go to bed at night, and after the students fall asleep normally, or the mobile phone jammer system is set It will automatically shut down after 2-3 hours of scheduled operation. This can ensure that students will not be obsessed with mobile games and chatting on the Internet after the lights are turned off, so that they can fall asleep peacefully to get enough sleep time and maintain strong learning energy!

Nowadays, many conference centers have installed mobile phone jammer systems. The main purpose is to allow the attendees to focus on the content of the meeting during the meeting, instead of sitting in the venue and constantly playing with their mobile phones. At the same time, there is a particularly important reason, that is to keep the mobile phones in the venue silent, so as to avoid some people who forget to set their mobile phones to silent. , Destroying the atmosphere of the meeting. If it is a single meeting room, you only need to choose the stand-alone version of the jammer. But now some meetings are arranged in special conference centers. These conference centers are specially built for various meetings. Usually, there are dozens of meeting rooms, large and small. If these dozens of meeting rooms are given the traditional If there is a way to purchase a stand-alone version of the jammer, this will obviously bring a lot of workload to the management staff. Therefore, how to carry out the construction requirements of the conference center on the mobile phone signal shielding function has a new development direction: the installation of the mobile phone jammer system in the conference center should be intelligent and centralized control and management as much as possible.

A large conference center may be distributed in several buildings or on different floors, and the conference rooms may not be exactly the same, and some conference rooms may be small conferences that only need to serve dozens of people , the area is only tens of square meters, and some meeting rooms may meet the needs of hundreds of people meeting at the same time, and the area will reach hundreds of square meters or even thousands of square meters. A small meeting room may only need to install one or two mobile phone jammers, while a meeting room over hundreds of square meters may need to install a large number of mobile phone jammers. In this way, the number of jammers in the entire conference center will be at least dozens. For these scattered jammers, it will be very necessary to establish a mobile phone jammer system with intelligent centralized control and management!

Customers can choose mobile phone jammers with intelligent networking functions in advance when selecting equipment at the beginning of project establishment, and reserve network interfaces in advance. By connecting to the network, a mobile phone jammer system with centralized control and management functions of smart goods can be quickly formed.

At that time, the management personnel of the conference center can realize remote management only on the main control software of the control center. They can choose to turn on or off the jammers in any meeting room at any time, and can also set up functions such as timing startup and timing shutdown. Even the mobile phone jammer system also has functions such as automatic fault detection and automatic alarm. In this way, the original maintenance method of relying on manual inspection one by one can be avoided.

When the mobile phone is within the effective shielding range of the mobile phone signal jammer, the phone’s voice call function and Internet data transmission and other functions will be cut off, and the signal grid on the top of the display screen will also disappear. At this time, the mobile phone is completely offline , Basic functions such as answering or making calls, sending and receiving text messages, chatting online, and playing games online cannot be used normally. At this time, some customers will ask questions: If the mobile phone signal jammer is turned off, how long will it take for the mobile phone to return to normal? Is it true that the mobile phone signal will be restored immediately when the mobile phone signal jammer is turned off?

The facts may be different from your initial assumptions: the mobile phone signal jammer has two different states of action on the mobile phone at the moment of turning on and turning off.

Let me first talk about what happens when the mobile phone signal jammer is turned on: as long as the mobile phone is not far away and does not exceed the effective shielding range of the shielding device, then at the moment of turning on the mobile phone, the communication functions (including voice and data) will be disabled. Immediately blocked, with almost no time difference between the two. Although some people may find that the signal grid does not disappear quickly or drop to zero when observing the signal grid on the mobile phone screen, but in fact the signal grid at this time is just a false display. Operate the mobile phone, trigger the external communication function of the mobile phone, and you will find that the display of the signal grid will quickly complete the status update.

Let’s talk about the performance process of the mobile phone signal jammer that was originally shielded by the signal when it was turned off or cut off the power supply after the mobile phone signal jammer was turned on for a period of time? Through observation, it can be found that the moment the mobile phone signal jammer is turned off, the mobile phone does not respond in a short period of time, and it is not possible to answer or make calls immediately, and it is not possible to quickly use the mobile phone to access the network. The signal grid is still displayed as no signal for a period of time at the beginning. Mobile phone users can only see that the signal of the mobile phone has finally recovered after waiting patiently for more than ten or even twenty seconds, and then they can use the mobile phone completely and normally. Why is this so? This is because after the mobile phone signal jammer is turned off, the signal recovery of the mobile phone must go through a process, that is, the process of handshake communication between the mobile phone and its surrounding base stations, identification, and registration to the network. The length of this process will be affected by several factors. Factors, including: different operators of mobile phones, different strengths of base station signals, different numbers of mobile phone users in the service area to which base stations belong, and so on.

Nowadays, many mobile phone users use dual-card mobile phones, that is, a mobile phone is installed with 2 SIM cards and has 2 mobile phone numbers, and the operators and mobile phone signal strengths of the 2 mobile phone numbers will be displayed on the mobile phone. on the screen. Then the question arises, when carrying a dual-card mobile phone into a workplace where a mobile phone jammer is installed, will a mobile phone jammer have the same shielding effect on the dual-card mobile phone? Is it completely shielding the mobile phone signals of the two SIM cards at the same time or will they have different shielding effects?

In response to this problem, we need to distinguish several situations for discussion. The first situation is that although the two SIM card numbers correspond to different mobile phone numbers, they both belong to the same communication operator, and the base stations currently registered to the network of the two SIM card numbers are the same base station. In this case, the strengths of the mobile phone signals received by the two mobile phone numbers in the mobile phone are almost exactly the same. Carry the mobile phone gradually close to the installation position of the mobile phone jammer, and the shielding effect reflected is basically the same. We will see that the signal of the two mobile phone card numbers of the mobile phone will gradually weaken until it completely disappears and the network is disconnected.

The second situation is that although the two SIM card numbers belong to the same operator, if it is a downtown area with many mobile phone users around, and there are many base stations, repeaters, and micro base stations, then the two SIM cards will It is possible to log in to different base stations and observe the signal strength on the mobile phone, and you will find that the signal strength of the two mobile phone numbers will be different. In such a situation, if the mobile phone is brought close to the mobile phone jammer, the effect of mobile phone shielding reflected will be different. It is possible that the signal that one of the mobile phone numbers has entered is blocked, while the other mobile phone number still maintains a signal and can still use this number for external communication.

The third case is that the two SIM card numbers belong to different communication operators. Since each operator has its own base station network, the two SIM card numbers will definitely be registered in different base stations. Because the base station is relative to the mobile phone user, the distance of the base station, the size of the base station’s transmission power, the installation height of the base station antenna, the angle and direction of the antenna’s radiation, and other factors will cause the signal strength received by the mobile phone user to be very different. The final result will be the same as the second case above. When the dual-card mobile phone is close to the coverage area of the mobile phone jammer, the mobile phone numbers of two different operators will still have different shielding effects. And if through detailed testing and comparison, we will even get some results like this: in the working environment of the same mobile phone jammer, the actual shielding distance will be different for mobile phone numbers belonging to different operators. The magnitude of this difference will vary with the working environment. The key factor affecting the magnitude of the change is the distance between the surrounding base stations in the working environment.

In some boarding schools, after the evening self-study, students return to the dormitory, pack up their belongings and wash up, and it’s time to turn off the lights and go to bed. They should go to bed early to ensure that they have enough energy to continue their classes the next day, but There are always some students who can’t control themselves well, lack self-discipline, and hide behind their backs and use their mobile phones secretly. The management teacher of the school is very troubled by this phenomenon, and wants to find a way to prevent students from using mobile phones, so they often consult with the manufacturer of our mobile phone signal jammer with such questions. However, some management teachers have additional ideas. For example, in addition to installing mobile phone signal jammers in the dormitory, is there any equipment that can be used to check and find out which student in a dormitory is using a mobile phone? Or you want to purchase a set of equipment that can be used to directly scan which mobile phone numbers are using mobile phones within a certain range.

Although we know that the original intention of the management teachers of these schools is good, the original intention is to find out students who use mobile phones during rest or sleep time, and stop them, which will help students maintain sufficient energy and devote themselves to the second time. In the middle of the day’s study. However, if you want to realize the above-mentioned functional idea, you can identify and discover unknown mobile phones through a simple handheld electronic product, which is actually quite difficult. Moreover, compared with installing mobile phone signal jammers in the dormitory building, such a solution may not necessarily be finally approved by the school.

Using mobile phone signal jammers to directly shield all mobile phone signals in the dormitory building seems a bit simple and rude, but it is a feasible solution with low investment cost and easy project implementation. In addition to choosing the method of blocking mobile phone signals, there are other ways, but there will be several difficult factors, which will cause the school leaders to give up that choice in the end. These factors mainly include: 1. There are electronic devices that can scan or identify mobile phone numbers within a certain range, but these are usually special-purpose devices, and schools do not have the qualifications to use such devices; 2. The low cost of signal jammers is different. Even if the school purchases dozens or hundreds of mobile phone signal jammers at one time, the total investment cost is not large. The school has the ability to bear this, but professional mobile phone detection equipment is often expensive. With an investment of hundreds of thousands of yuan, ordinary schools are not willing to bear such a large amount of expenses. 3. The use and maintenance of the mobile phone signal jammer is very simple, basically it is to execute the power on, power off or even set the timer switch. However, professional mobile phone detection equipment must be operated by technical personnel with certain professional skills.

In order to prevent others from secretly installing positioning devices on their vehicles, thereby revealing personal privacy or revealing their whereabouts, some customers order some common GPS signal jammers from the Internet and want to install them on their cars. I think that after taking such a move, I can protect myself. Unfortunately, if you are not familiar with the working principle of the device, you just buy a GPS signal jammer, which often backfires. After a period of time, you find that your whereabouts are still being controlled by others. Why is this? Can car GPS signal jammers effectively prevent tracking and positioning?

This has to be analyzed from two aspects: the first is to understand what type of positioning device is installed on your vehicle. Of course, as the person concerned, he must not know where others will install the locator on the vehicle, so naturally he cannot know what type of positioning device it is. We can only take into account all the positioning methods that the positioning device can take. The reason why the positioning device can realize the positioning function and send the position information to the remote receiving terminal will use at least two signal types. The first type is GPS positioning signal. The GPS positioning referred to here is just a general term. It not only includes the United States GPS satellite positioning signals, including at least China’s Beidou satellite signals, Russia’s GLONASS satellite navigation signals, European Galileo satellite signals, and so on. The second type is data transmission signals. Data transmission usually adopts the built-in mobile phone SIM card, and uses the mobile phone’s 3G, 4G or 5G network signal to receive and send data to the receiving end. At the same time, the use of mobile phone SIM cards can also take into account non-precise positioning in a rough range, which is mainly achieved through mobile phone base stations. Compared with GPS positioning signals, its positioning accuracy is much worse.

On the other hand, or to realize that the vehicle-mounted GPS signal jammer can effectively prevent tracking and positioning, it is necessary to carefully check the specific technical indicators and functional parameters of the device when purchasing a vehicle-mounted GPS signal jammer. For the sake of low price, some customers choose devices that only have GPS signal interference, ignoring the interference that should be aimed at both mobile phone positioning and mobile phone data transmission signals. This is the real reason why some vehicle-mounted GPS signal jammers are obviously working all the time, but they still cannot effectively prevent others from tracking and positioning.

Even if the above two aspects are well considered, there is still an important matter that users must pay attention to seriously: if it is necessary to prevent tracking and positioning uninterrupted throughout the whole process, then it is necessary to ensure continuous power supply and continuous switching work of the car GPS signal jammer, any time It cannot be turned off during the period. Since the positioning equipment concealedly installed in the car is always working, once the vehicle-mounted GPS signal jammer cannot transmit interference signals due to abnormal power supply, even a short gap time may still cause the leakage of positioning information.

A fact about mobile phone numbers that mobile phone users in various countries will know is that when selecting a mobile phone number, the mobile phone number belongs to a certain communication operator. The carrier provides and charges for basic communication services to the mobile number. Usually, there are at least three or more communication operators in each country. Assuming that in a usage environment, there are mobile phone numbers of different operators, that is, different mobile phone numbers, then the question arises: Can mobile phone jammers selectively block signals for numbers of different operators?

To answer this question, you need to know in advance which country you are in, and you need to know how many communication operators there are in that country, as well as the division standards of mobile phone frequency bands in that country, and which operators specifically use when deploying base stations. frequency band. When the information is fully grasped and handed over to our mobile phone jammer manufacturer, then we can individually customize signal shielding modules for different operators based on these frequency band division standards. Therefore, in the process of implementing signal shielding, mobile phone numbers belonging to different operators can be selectively shielded.

What needs special attention here is that the shielding module in the mobile phone jammer can modulate the frequency range. The so-called signal shielding for different operators is actually to modulate the frequency of its shielded signal to the corresponding base station. Frequency, only when the operating frequency of the operator is strictly differentiated and there is no overlapping frequency band, the shielding effect mentioned above can be achieved. In reality, operators in some countries, due to the large number of communication operators and the tight spectrum allocation resources, will appear that multiple operators share the same mobile phone frequency. In this case, conventional mobile phone jammers Targeted signal shielding cannot be achieved.

Another point needs to be emphasized: the above is not a selective blocking of a specific mobile phone number. For example, there are 2 different mobile phone numbers, but they belong to the same communication operator. When within the effective shielding range of the jammer, the two mobile phones will be shielded at the same time. Unless the two mobile phone numbers belong to different operators, and the mobile phone jammer installed on site happens to be a customized product, when the mobile phone signal of the targeted operator is blocked, the two mobile phones will show that one mobile phone can Normal communication, but the result of another mobile phone not working normally.

Some customers will put forward such requirements when purchasing mobile phone jammers from us: In addition to completely shielding all mobile phone signals, the shielding device also needs to be able to effectively shield satellite phones. So is this requirement difficult to fulfill? Can mobile phone jammers be shielded together with common satellite phones?

This demand is actually not difficult for our mobile phone jammer manufacturers to solve. If we evaluate whether the function can be realized and whether the technical indicators meet the standards, we have no problem in realizing it. But the actual problem is: What type of satellite phone does the customer refer to? , because the answer to this question directly affects which satellite signals need to be jammed and blocked.

There are many brands and types of satellite phones, and the technical indicators are also very different. However, the most commonly used satellite frequency is the L-band, and the working frequency is 1616-1626.5MHz. The typical representative product is the Iridium phone. If you just need Complete the shielding of the Iridium satellite phone, then the solution is very simple, just add a 1.6G frequency band shielding module to the shielding module of the mobile phone jammer. Moreover, the shielding module only needs 2-3W of transmission power, which is enough to make the Iridium satellite phones within a radius of tens of meters around the mobile phone jammer unable to use normally.

If the satellite phone the customer refers to is a type of satellite phone other than the L-band, the result will become very tricky, because there are indeed some satellite phones that use the KA band, and some countries or regions even use it. More standard frequency bands, such as UHF band, C band, X band, K band… Or if you want to take all these frequency bands into consideration, the installation space in a mobile phone jammer is not considered as surplus, and it must be difficult to accommodate the shielding modules of so many frequency bands at the same time.

If all satellite phones are completely shielded, our suggestion may be to split the mobile phone jammer into two hosts, one of which is dedicated to all mobile phone signals, and the other The mobile phone jammer is actually installed with modules targeting all satellite signal frequency bands, and its real name can also be directly called a satellite mobile phone jammer.

If you look back at the hand-held portable mobile phone jammers ten years ago, you will intuitively feel that the shape of the hand-held shielding devices at that time was so small that it could be held completely with one hand. Their hosts, including antennas, are all Sizes including, will not exceed the range of one hand. At that time, such mobile phone jammers were favored by many customers. After some customers purchased them, they could be used directly in their pockets or handbags. But today, we can no longer see such a small and exquisite handheld shielding device. This is not because there is no customer demand, but the actual situation is that with the continuous upgrading of mobile phone communication technology, various manufacturers basically can no longer produce it. What are the technical bottlenecks encountered in the development of portable mobile phone jammers?

Ten years ago, 2G and 3G mobile phones were widely used. At that time, 4G communication technology had not yet been put into use, and 5G communication was out of reach. When there are only 2G and 3G mobile phones, or to achieve complete shielding of mobile phone signals, it is only necessary to perform signal shielding on the communication frequency bands used by these mobile phone standards. The frequency bands of wireless frequencies used by 2G and 3G are: 800MHz, 900 MHz, 1800 MHz, and 2100 MHz, a total of 4 frequency bands. If you add the standard WiFi2.4G/Bluetooth on the mobile phone, that is, the 2400 MHz frequency band, there are a total of 5 signal frequency bands that need to be shielded. From this point of view, it is not too complicated and difficult to integrate 5 signal shielding modules and supporting power boards, main control boards, power supply batteries, and transmitting antennas into a small handheld terminal.

However, the development of mobile communication technology is non-stop. In just ten years, 4G and 5G have been launched one after another and have been widely used. However, the launch of 4G and 5G does not directly follow the original communication frequency bands of 2G and 3G, but newly enables several high-frequency frequency bands, including: 700 MHz, 1900 MHz, 2300 MHz, 2600 MHz, 3400 MHz , 4800 MHz, etc. In addition, current smartphones use dual-band wireless network technology, and the two frequency bands of WiFi2.4G/WiFi5..8G can be selected and switched at will. These newly added frequency bands are added to the 2G/ The 5 frequency bands of 3G are obvious: if a mobile phone with 5G function needs to be effectively shielded, then this mobile phone jammer will include at least 10-12 shielding modules.

The number of modules for shielding signals has reached 10-12, which has brought great difficulties to the manufacturers of mobile phone jammers, especially how to miniaturize the mobile phone shielding equipment, how to reduce the appearance size as much as possible, Lightweight and long enough battery life? It is not difficult to see the pain points and difficulties that restrict the hand-held and portable mobile phone jammers.

It is precisely because the number of modules includes at least 10-12, which is at least one more than the small equipment ten years ago, and the increased frequency band modules themselves need to have enough installation space, and the number of antennas corresponding to them must also be increase, the capacity of the battery powering it must also increase accordingly. These problems follow one after another, and each problem will bring great difficulties to the portability and miniaturization of mobile phone jammers.

All customers who have purchased mobile phone jammers are very concerned about the actual shielding effect of the shielding device when they receive the product and conduct a power-on test. Different customers must have differences in the test environment, the method of testing and the testing methods. There are also differences in the mobile phones used, so there will be large differences in the test results returned. Among them, the placement or installation position of the shielding equipment is also a key factor affecting the shielding effect. Then the question arises, if the mobile phone jammer is placed directly on the ground, how effective is it?

Usually, when the manufacturer of mobile phone jammers sells the shielding equipment, there will be a detailed installation and use instruction in the package box of the goods. Let us take the most common low-power mobile phone jammers used in indoor environments as an example. There should be special installation instructions in the manual. The first choice is wall-mounted installation. It is recommended that the user keep the installation height of the shielding device between 1.8 meters and 2.5 meters, because this height is just at a position that is not easily accessible to human hands, which can prevent future use. During the process, someone will maliciously damage the shielding device or artificially cut off the power or shut down. At the same time, this installation height also exceeds the height of almost all furniture, tables, chairs or other furnishings in the room, so that the shielding signal of the mobile phone signal jammer can be transmitted unimpeded, and the shielding signal can be covered to every room in the room to the greatest extent. corner.

If it is inconvenient to use the wall-mounted installation method, but directly place the mobile phone signal shielding device on the table, this can be regarded as a compromise method, which is suitable for short-term and temporary work scenarios. Since the height of the conventional desktop is about 0.8 meters, if the mobile phone jammer is placed directly on the desktop, the shielding signal will be more or less affected by some furniture or obstacles with a height of more than 1 meter during the transmission to the surroundings. Influenced by objects, this will actually reduce the final shielding effect.

Finally, analyze what will happen if the mobile phone jammer is placed directly on the ground: unless the room is completely empty, the tables, chairs or furniture in the room will become obstacles in the process of shielding signal transmission. More or less will attenuate the shielding signal, and this attenuation will be superimposed as the number of obstacles increases. This will seriously affect the shielding distance of the mobile phone jammer. It is the most undesirable way to use the shielding device on the ground for testing and use.