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There are many difficulties in detecting and tracking UAV countermeasures targets. In terms of radar detection, radar detection is currently an important method for detecting UAV targets, but radar detection cannot detect all moving targets.

There are many difficulties in detecting and tracking UAV countermeasures targets. In terms of radar detection, radar detection is currently the main method for detecting drone targets, but radar detection will not respond to all moving targets; drones are generally made of balsa wood and composite materials. This material It has the characteristics of transparency, which makes it have low detectability. It can only be made of stainless steel such as motors, engines, batteries, power lines, etc., coupled with its small size, which greatly reduces the radar detection transmission area of ​​the target itself. , reducing the distance and probability of detection by radar, and also reducing the time for road reflection.

In terms of acoustic detection, the noise of UAV targets is mainly engine noise and gas oscillation noise generated during the flight. However, at present, a large part of the driving force of UAV targets is electric power, and the noise is relatively small. Coupled with the relatively slow flight speed, the noise level is very low. In terms of optical detection, at present, most air defense guns use infrared fire control technology, and a very large number of surface-to-air missiles and air-to-air missiles also use infrared detection and infrared guidance technology; laser rangefinders and laser target indicators are used in short-range civil air defense It has been widely used in weapons and equipment.

signal jammer

The motor or engine used as the driving force of the UAV target is small in size and high in efficiency, and its infrared radiation characteristics are low, which makes the detection distance through infrared detection greatly shortened. In terms of anti-laser detection, UAV targets are easy to use such as inhalation Materials such as waves, scattering, and light guides, reducing the laser reflection surface and hiding the design concept in the appearance, etc., all make optical detection more difficult.

Now more and more people are using the car GPS locator. Whether it is a company or a private car, GPS is already very common. Installing the GPS locator on the car can make the company or car owner quickly find the car on the GPS monitoring platform Essence However, some criminals use the function of GPS positioning to install the GPS positioner on other people’s vehicles to obtain other people’s itinerary information, privacy information, etc., and wait for the opportunity to perform illegal acts such as theft. In order to prevent the leakage of their itinerary information, many car owners will block the GPS positioning illegally installed on their own vehicles. How can the car GPS positioning block?         signal jammer

There are the following methods for car GPS positioning shielding:

1. Generally speaking, the car GPS positioner uses GPRS and CDMA to transmit signals. You can find a phone card. If so, you can remove the signal;

2. You can also find the power supply of the positioner directly, pull the power supply, and the positioner cannot receive the signal;

3. Buy some anti -GPS positioner, anti -GPS tracker, GPS jammer, GPS shield, GPS blocking device. These can shield the position signal of the car GPS.

Anti -positioning shielder can make the GPS locator fail within the specified electromagnetic band by releasing radio waves, forming the purpose of using the same electromagnetic environment as the equipment to use the same electromagnetic environment. The GPS positioning shield can be shielded by the GPS satellite signal, so that the data cannot upload the platform to make the device be used normally.

With the development of drone technology, drones have been widely used in military, civilian, commercial and other fields, bringing convenience and fun to people. However, drones also have some safety risks, such as illegally invading no-fly zones, carrying dangerous goods, conducting illegal surveillance or attacks, etc., posing threats to national security, public safety and personal privacy. In order to effectively prevent and respond to these threats, countries are developing and using various drone countermeasures, one of which is the gun-type drone jammer.  signal jammer

The gun-type drone jammer is a gun-shaped electromagnetic interference device that can interfere with and intercept the control signals, navigation signals and image transmission signals of the drone by emitting high-power radio waves, forcing the drone to aircraft to land or return. The working principle of the gun drone jammer is as follows:
1. The gun-type drone jammer has built-in transmitting modules for multiple frequency bands, which can cover the frequency bands commonly used by civilian drones on the market, such as 2.4GHz, 5.8GHz, 1.2GHz, etc.

2. The gun-type UAV jammer emits a high-power shielding signal in the target direction through the antenna, forming a directional interference magnetic field.

3. When a drone enters an interference magnetic field, its control signal, navigation signal and image transmission signal will be strongly interfered, resulting in losing contact with the remote control or base station, or receiving erroneous data and instructions.

4. Due to the loss of normal communication and navigation functions, the drone will initiate a preset fault handling mode according to its own flight control system, such as automatic landing or return.

Gun drone jammers have the following advantages:
1. Easy to carry: The gun-type drone jammer adopts a lightweight gun-shaped design and is powered by a built-in lithium battery. It can be used in hand or on the shoulder, making it suitable for mobile combat.

2. Simple operation: The gun-type UAV jammer only needs to press the switch button and emit the shielding signal in the target direction to achieve jamming and interception of the UAV without complicated settings and adjustments.

3. Wide coverage: The gun drone jammer can support shielding signals in multiple frequency bands, and can effectively interfere and intercept most civilian drones on the market, regardless of the drone model and standard. limit.

4. Remarkable effect: The gun-type drone jammer uses a high-power transmitting module and a directional antenna to form a strong interference magnetic field, which can cause a fatal blow to the drone and prevent it from flying and operating normally.

Gun-type drone jammers can be used in the following scenarios:
1. Military defense: Gun-type drone jammers can be used in military bases, important facilities, border posts and other places to prevent enemy drones from conducting reconnaissance or attacks and protect national security and military secrets.

2. Public safety: Gun-type drone jammers can be used in government agencies, public places, major events and other places to prevent terrorists or criminals from using drones to conduct illegal activities and maintain public order and social stability.

3. Personal privacy: Gun-type drone jammers can be used in private residences, offices, hotels and other places to prevent criminals from using drones to peep or eavesdrop, and to protect personal privacy and business secrets.

4. Other uses: Gun-type drone jammers can also be used in wild adventures, wildlife protection, forest fire prevention and other scenarios to prevent drones from causing damage or impact on the natural environment and ecosystems.

In order to ban students from using mobile phones, a private middle school in Zhengding County (Hebei) installed multiple mobile phone signal jammers on the roof of the school’s teaching building. Now the students can no longer use their mobile phones, but because the instrument is located on the roof and the surrounding area is very empty, surrounding residents have also been seriously disturbed when using their mobile phones. On March 25, the Shijiazhuang Radio Administration Bureau of Hebei Province ordered the school to dismantle the rooftop equipment in accordance with relevant regulations. However, the school stated that the use of mobile phones has a great negative impact on students’ normal learning, and how to effectively supervise it has become a problem.

Complaint: Cell phones frequently malfunction around the school

According to an operator in Zhengding, for a long time, the company has frequently received reports from residents in the northeastern area of Zhengding County that their mobile phones often appear intermittent when making calls. The company sent personnel to check the signal base station many times and found no problems. Therefore, it sought help from the Shijiazhuang Radio Administration Bureau to investigate the sources of radio signal interference in the area.  signal jammer

On March 25, the Shijiazhuang Radio Administration Bureau sent law enforcement officers and radio monitoring vehicles to the northeastern part of Zhengding County for testing. After investigation, the staff initially detected that the signal interference was strongest at a private middle school in the northeastern area of the county. When the staff talked with residents around the school, they confirmed that the problem of mobile phone use in the area was indeed serious, but the residents did not know the reason.

Install shielding equipment on school roof

Detection by radio direction finding and positioning instruments showed that the source of interference was on the campus of this private middle school. After entering the campus, the staff discovered that all the buildings in the school were bungalows, and a yellow box-like device was installed on the roof of many of the teaching buildings. Tests with professional instruments showed that the device emitted radiation with a strong frequency, and the signals from the mobile phones carried by the staff completely disappeared. The school admitted that the device was a “mobile phone signal jammer” and that the jammer was turned on because the senior high school students were taking a mock exam that day. It is reported that the transmitting frequency of this instrument has multiple frequency bands such as 800 MHz and 1800 MHz. These frequency bands include frequency bands used by communication operators.

According to the school leaders, students’ use of mobile phones affects their studies. In order to ban the use of mobile phones, the school invested heavily in purchasing and installing “mobile phone signal jammers” and installed them on the roof. “I didn’t expect it would have an impact on the lives of surrounding residents,” the person in charge said. The instrument’s packaging clearly stated that the effective range is 30-50 meters. “How could the impact range be so large?”

According to the staff of the Radio Administration Bureau, since the installation site is on the roof and there are no surrounding buildings to block it, when the jammer is turned on, the interference range will expand.

According to reports, there are relatively strict regulations on the use of mobile phone signal blocking devices, and they can only be used in major national examinations, high-level meetings and other occasions. This private middle school also uses this kind of equipment in daily teaching, which affects the normal lives of surrounding residents. The Shijiazhuang Radio Administration Bureau ordered it to remove the mobile phone signal jammer in accordance with the law.

Supervision of students’ use of mobile phones is a problem

The person in charge of the private middle school said that the use of mobile phones has a great negative impact on students’ normal learning. The only purpose of many students using mobile phones is for entertainment, playing games, chatting online, and even looking for pornographic information. Many teachers are very worried. “The school cannot search one by one at the school gate, nor can it monitor every student 24 hours a day. There are great difficulties in monitoring mobile phones. After we purchased these devices, students’ use of mobile phones has been greatly reduced.” However, high-tech means are relied on to interfere with mobile phones. The signal was not allowed by the national radio management department, and the school expressed its helplessness.

A parent of a high school student also told reporters that for the convenience of communication, he once gave his child a mobile phone with the simplest functions, but within a few days his child asked for a high-end mobile phone. “My classmates often joked that his mobile phone could not keep up. “Era,” the parents were very angry after hearing their children’s story. Not only did they not buy new mobile phones, they even confiscated the old ones. “Mobile phones have become something for students to satisfy their vanity.”

A sophomore girl from Shijiazhuang No. 2 Middle School told this reporter that the No. 2 Middle School did not completely ban students from using mobile phones. It only stipulated that use is prohibited in the teaching building. There are no requirements outside the teaching building. Students use mobile phones voluntarily. Some parents believe that as long as their children can control themselves, there is no problem in using mobile phones, but necessary supervision is still needed.

So, how can schools effectively supervise students’ use of mobile phones? Professor Shi Guoxing from the School of Education of Hebei Normal University said in an interview with reporters that mobile phones do more harm than good to the learning of students, especially primary and secondary school students with relatively poor self-discipline, so it is necessary to restrict their use. Although the practices of this private middle school in Zhengding have affected the lives of residents outside the school and should be corrected, it is also a helpless move by the school. Since cell phones cannot be kept out of school by blocking signals, it is recommended to use more diversion methods, adopt a compromise plan, make different requirements for different students at different times, and standardize the use of students’ cell phones through the joint efforts of parents and teachers. .

United States: Opposition to the use of mobile phones on campus is strong. Currently, most schools in the United States do not allow students to use mobile phones. In Georgia, students are strictly prohibited from using mobile phones before school ends at 15:00. Once a student violates the rules, the teacher can confiscate the phone and impose disciplinary penalties on the person involved.

Finland: Selling mobile phones to teenagers is prohibited. The Finnish Market Court recently decided to prohibit Finnish wireless communication companies from directly selling mobile communication services such as mobile phone access to the Internet to teenagers. Violation of this ban will result in a fine of €100,000.

UK: The British Ministry of Education sent a letter to principals of schools in the UK, making it clear that except in emergencies, students under the age of 16 are not allowed to use mobile phones. A government research report “Mobile phones may harm children’s health” is also attached to the letter. . There is no clear evidence in the report that the radiation from mobile phones is harmful to the human body, but it is believed that because children’s nervous systems are not fully developed, their heads are smaller, their skulls are thinner and other physiological reasons, they will absorb more radiation from mobile phones, which is harmful to health. constitutes an “undetermined” hazard.

A signal jammer is an important electronic device used to block the transmission of wireless communication signals. In modern society, we sometimes need to use signal jammers to cut off wireless communications and prevent information leakage. Therefore, the debugging of signal jammers is crucial. This article will introduce you to several common signal shielding instrument debugging techniques to optimize the stability of the equipment’s operation.  signal jammer

1. Make sure the device is connected correctly. First, check whether the signal shielding device is connected correctly to other devices. Signal jammers usually need to be connected to radios, antennas and other equipment. Make sure that all interfaces are connected firmly and correctly to avoid signal instability or failure to shield during the operation of the signal shielding device.

2. Check the power settings of the signal jammer. The power setting of the signal shielding device is crucial for stable signal shielding effect. During the debugging process, we can reduce the power of the signal shielding device to observe whether the signal is intermittent. If the signal shielding effect is not good, you can gradually increase the power until the ideal shielding effect is achieved.

3. Find possible sources of signal interference. During the debugging process of the signal shielding instrument, we need to investigate possible sources of signal interference. Common sources of interference include electronic equipment, communication facilities, etc. By eliminating these interference sources one by one, we can more accurately locate which device or signal is interfering with the work of the signal jammer. Once the source of interference is found, appropriate measures can be taken to solve the problem, such as changing the location of the equipment or adding shielding materials.

4. Use appropriate shielding materials. Signal jammers typically use one or more materials to block wireless communication signals. Choosing the right shielding material is crucial for debugging the signal shielding device. Different materials have different shielding effects and transparency. We need to choose the appropriate shielding material according to specific needs and ensure its quality and durability.

In mobile phone shielding projects, the reasons for different signals caused by external and environmental factors are:
1. Due to the different power and number of channels of base stations such as China Mobile, China Unicom, and China Netcom, the distance between the base station and the prison, and the different sizes of other nearby buildings, topography, and landforms, the signals in the prison area are also different.  signal jammer
2. Due to the different characteristics of the actual use environment, the direction, power, distance and distance of each base station, there may be dozens of channels for the user’s mobile phone to automatically select in the same environment. At the same time, there are spatial field strength differences indoors and outdoors. Ground and metal Objects cause very complex adverse effects on signals blocked by mobile phones. So we all have this experience, for example: (a) In different areas, some mobile signals are strong, and some China Unicom signals are strong: (b) Even in the same place, the signals are also different, some are strong and some are weak, so mobile phones The signal shielding system is a highly professional system project.
Measures taken for the above reasons:
1. Conduct a detailed on-site survey of the prison environment, topography, landforms, etc., very carefully. The survey needs to shield the regional environment, understand the actual requirements of the customer, and design personalized solutions. Therefore, special project investigation and solution must be carried out to comprehensively solve problems for customers in a scientific and systematic manner.
2. Thoroughly analyze the local signal distribution and building structure. It is positioned using non-general equipment and measured by a series of instruments. Choose different composite antennas based on the organic combination of antenna application principles in different frequency bands.

In the digital age, mobile phones have become an indispensable communication tool for everyone. However, in certain situations such as examination rooms, conference rooms, etc., communication may cause bad results. Therefore, a high-quality and efficient mobile phone shielding system is particularly important. This article will delve into the relevant strategies and technologies for building a high-quality and efficient cell phone blocking system.   signal jammer

The necessity of mobile phone blocking system
Cell phone blocking systems, as the name suggests, are devices used to cut off cell phone signals to prevent communication devices from being used in specific areas. In the examination room, the mobile phone signal blocking system can prevent the occurrence of fraud; in the conference room, it can ensure the confidentiality of the meeting and not be disturbed; in areas such as prisons, it is part of the security management to prevent the occurrence of illegal communications . Therefore, the role of mobile phone blocking systems in different fields cannot be underestimated.

Principle of shielding system
To understand a quality cell phone blocking system, you first need to understand its basic principles. Simply put, mobile phone shielding devices interfere with the normal reception of mobile phone signals by emitting the same frequency signal that communicates with mobile phones, making the mobile phone unable to make and receive calls normally. This principle is similar to playing multiple sound sources in a room, eventually leading to the inability to recognize the original sound.

System Design Considerations
1. Environmental adaptability. Before designing a shielding system, the first thing to consider is environmental factors. Different environmental conditions, such as wall material, space size and surrounding electromagnetic environment, will have a significant impact on the shielding effect. Therefore, environmental conditions should be fully considered at the beginning of the design to ensure that the screen system can adapt and operate efficiently in the specific environment.
2. Coverage. Considering shielding range is another key point in the design of a quality and efficient mobile phone shielding system. Designers need to determine the screen range through calculations and ensure that the signal completely covers the area where the screen is required, while avoiding any impact on normal communications in surrounding areas.
3. Legal compliance. The country has strict laws and regulations on communication signal shielding. When designing a shielding system, you need to strictly abide by relevant laws and regulations. You cannot shield signals at will, otherwise you may be suspected of violating the law. Therefore, designers need to understand and follow local regulations and standards in detail when building screen systems.
4. Technical parameters. Technical parameters are the top priority in building an efficient mobile phone shielding system. This includes the frequency, power, size, signal emission stability, etc. of the mobile phone signal shielding system. These technical indicators affect the quality of the shielding effect and whether it can work stably and for a long time. High-quality technology and components must be used to build a mobile phone shielding system that is both safe and reliable.
5. User interface and ease of operation. Taking into account the user’s operating habits and convenience, a friendly user interface can be integrated into the mobile phone shielding system to ensure that even non-technical personnel can quickly understand and operate. At the same time, necessary operation guides and fault diagnosis tools are provided, which can greatly improve the user experience of the system.

In a prison environment, maintaining security and control over communications is critical. Cell phone signal blocking systems not only prevent illegal communications but also enhance overall security management. This article will introduce in detail the installation steps, maintenance points and solutions to common problems of the mobile phone signal blocking system in prisons.  signal jammer

Detailed explanation of steps 1. planning and design

Needs Assessment: First, assess the type and number of shielding systems required based on the prison’s layout, building materials, and signal coverage needs.

System Design: Design a comprehensive installation plan including equipment location, power configuration and signal coverage.

2. Installation process

Equipment placement: Install the signal jammer at the designated location according to the design drawings. Make sure all equipment is installed in a location that maximizes coverage area and is less likely to be vandalized.

Power connection: Connect to a stable power system. For equipment that requires high power output, ensure that the power line is safe and reliable.

3. System configuration

Frequency settings: Set the frequency and power of the shielding system according to the prison’s internal communications policy and external regulations. Ensure settings comply with legal requirements while effectively blocking illegal communications.

Testing and debugging: After completing the initial installation, conduct system testing to check whether the signal coverage is uniform and effective. Adjust device settings until optimal performance is achieved.

4． final acceptance

Performance verification: Test system performance multiple times at different times and under different weather conditions to ensure stable operation under all circumstances.

Documentation archiving: Record installation details, configuration settings, and test results to provide reference for future maintenance and upgrades.

The United States’ confidence in the Iraq war is largely based on high-tech military equipment. Guided bombs such as JDAM can theoretically carry out precise “surgical” strikes against hostile parties. The Iraqis used low-cost signal jammers in an attempt to jam the mythical Global Positioning System (GPS) weapons guidance signals.  signal jammer
This kind of GPS jammer is only the size of a mobile phone and can be purchased in the market for a few hundred dollars. The Iraqis regard it as a magic weapon to “defeat foreign artillery” – it is said that it can interfere with the GPS signal, thereby allowing the Americans to accurately The weapon was “hitting crookedly.” It is said that the US military has found and destroyed 6 such jammers in Iraq.

The US military’s “Global Positioning Satellite System” is a signal network composed of 27 satellites. It can not only position and control weapons, but also provide navigation for troops and aircraft accurate to meters. If the GPS signal can be interfered with for a long time, it will cause the entire logistics system of the US military to malfunction.

Before the war began, U.S. military experts warned that the Iraqis’ GPS jammers might disable U.S. guided bombs. Douglas Lowero, the person in charge of the GPS system program in the United States, believes that this is nonsense. There is no instrument on the market that can effectively interfere with GPS signals.

How powerful is this gadget?

A Russian company makes such a cheap GPS jammer. Theoretically, this jammer can interfere with satellite signals within a radius of 200 kilometers. The signal sent by U.S. navigation satellites to the GPS receiving antenna is very weak, and its strength is only about one billionth of the signal received by a general TV antenna. Therefore, satellite navigation systems commonly used in automobile transportation, navigation and adventure travel are very susceptible to interference from such GPS jammers. However, navigation equipment used for military purposes is relatively “robust” and less susceptible to interference.

The “C/A” code of the GPS system is used for civil purposes, and its positioning accuracy can reach about 5 meters. The military uses the “P” code, which has a positioning accuracy of up to one meter.

Not only is the military’s “P” code more precise, it’s also encrypted and therefore less susceptible to interference. Douglas Lowero believes that military GPS codes are thousands of times more resistant to interference than civilian codes. He said that GPS jammers are only effective within a radius of a few kilometers. At most, they can only interfere with GPS-guided weapons within this range, and it is impossible to make guided weapons stray.

In addition to satellite positioning systems, the U.S. military’s precision weapons are also equipped with another navigation mechanism-the Inert Navigation System (TNS). The TNS system will not be interfered by external signals. Its working principle is to use the inertia of the high-speed rotating gyro system for positioning. Before the precision bomb is launched, the TNS system is input with a set of parameters that define its starting position; after the bomb is launched, the gyro system interprets each trajectory change relative to the starting position as a steady-state disturbance, thereby performing a new position calculation. describe.

The positioning error of a GPS-guided bomb is about 3.5 meters, while the positioning error of TNS is about 20 meters. If used to attack military installations, this positioning error of TNS can be ignored. However, if it is used to attack military targets in residential areas, the possible consequences of this error cannot be underestimated.

The mobile phone signal jammers purchased by the school in previous years did not have the function of interfering with 5G signals because 5G had not been launched when they were originally purchased. In the current use of signal shielding in examination rooms, they can no longer shield 5G signals. This leaves school examination room users faced with the problem of how to upgrade or replace the original mobile phone signal jammer. So how should you choose a 5G signal jammer during school exams? signal jammer
School examinations require the use of 5G signal jammers for examination room management to ensure that candidates will not be affected by wireless signals from the outside world. Therefore, it is recommended to consider the following points when choosing a 5G signal jammer for school exams:

1. First, make sure that the selected 5G signal jammer can block the signal in the 5G frequency band. Generally speaking, the frequency bands of 5G signals are divided into mobile 5G (2515MHz-2675MHz, 4800-4900MHz), China Unicom 5G (3500MHz-3600MHz), China Telecom 5G (3400MHz-3500MHz), radio and television 5G (703MHz-733MHz, 758MHz-788MHz, 4900MHz -5000MHz), so you should purchase a jammer that supports these frequency bands.

2. Choose a brand or model with good shielding effect. You can refer to some well-known domestic and foreign brands or models with a certain reputation in this field for comparison. Of course, you should also choose a signal jammer model with appropriate power based on your own usage scenario and environment to purchase a 5G signal that suits your needs. jammer.

3. Consider purchasing a multi-functional model that has other functions besides shielding, such as shielding GPS, Bluetooth, WIFI and other wireless signals, in order to adapt to the shielding requirements of different types of communication equipment in exam scenarios.

4. Finally, the price of the signal jammer must be considered. After all, the budget cost of some school examination rooms is limited, so it is necessary to choose signal jammer products with high cost performance. Of course, in addition to considering the price, the quality and performance of the 5G signal jammer should be given priority. Choosing a high-quality and high-performance 5G signal jammer can provide better protection and security for the exam process.