カテゴリー別アーカイブ: 未分類

Security monitoring has become one of the most important components of our security work. From front-end high-definition cameras to network transmission monitoring, to back-end storage and high-definition video display, the increase in investment costs alone is enough to explain the importance of video surveillance in the entire security project. However, in the daily use of the monitoring system, there are often some interferences that prevent the monitoring system from working properly. So is there any way to eliminate these interferences? Let’s talk about some of the “most” interference removal methods.

1. The most common: wood grain interference   signal jammer
In daily use, wood grain interference is one of the most common interferences. There are many reasons for this interference, the most common of which is defects in the video transmission cable. In addition to problems with the line itself, wood grain interference is sometimes caused by strong current interference near the transmission line. Of course, to deal with current interference, you only need to use purified power supply or online power supply in the entire system. Regarding this problem, the solution is to strengthen the shielding of the front-end equipment, or ground the video cable.

2. Maximum area: reticulated interference
In addition to wood grain interference, there is also mesh interference that may occasionally affect visual viewing. Among common interference images, the area affected by pattern interference should be considered the largest. Although the interference area is large, the processing is not as “domineering” as it seems.

Regarding the origin of this interference, it is usually caused by a small short circuit or open circuit between the transmission core of the video cable and the surrounding protection network. Therefore, this problem often occurs with BNC connectors or many other types of connectors. The solution is to check the corresponding connectors one by one and replace the problem equipment in time, so you can easily get rid of the confusion of this kind of interference.

3. The most organized: vertical bar interference
Although this type of interference is uncommon, its characteristics are very obvious. The main reason for the formation of vertical bar interference is that the quality of the cable does not meet the specifications, resulting in abnormal associated data during the transmission process. Therefore, when dealing with this kind of interference situation, the method of “connecting a resistor in series at the beginning” or “connecting a resistor in parallel at the terminal” can be used. Of course, the best way to prevent this kind of interference is to strictly control product quality during the wiring process.

From 1994 to 1998, many actual tests were conducted on “Big Brother”, “Second Brother”, walkie-talkies and other mobile phones. The actual measurement methods used the simulation comparison method and the simulation method. The test results are now listed in Table 5-1.   signal jammer
The actual measurement results show that the radiation field strength of different types of mobile phones produced by different manufacturers has certain differences. Generally speaking: the electromagnetic radiation field strength of “Big Brother” is about several hundred μw/c㎡; The electromagnetic radiation field strength is about several thousand μw/c㎡; the radiation field strength of the walkie-talkie is about 1-4 thousand μw/c㎡.
Through multiple organized measurements of the incoming field strength of electromagnetic radiation from mobile phones, it can be seen that a considerable proportion of mobile phones that have been put into use have excessively high radiation levels. According to my country’s international GB10436-89 hygiene standard for microwave radiation in workplaces: the average power density of continuous wave exposure for 8 hours a day is 50 microwatts/cm2; GB9175-88 hygiene standard for environmental electromagnetic waves: the allowable microwave field strength (middle zone) is For evaluations of less than 40 microwatts/cm2, 65~70% exceed the standard.

The huge increase in mobile phone users has brought about some unexpected serious consequences: using mobile phones while flying can interfere with the aircraft’s navigation system and cause plane crashes; using mobile phones in hospitals can interfere with hospital ECG monitors, hemodialysis machines, and automatic injection machines. The normal operation of medical equipment such as heart pacemakers and pacemakers can put patients’ lives in danger; using mobile phones at gas stations interferes with technical systems and even causes fires… The tragedies caused by improper use of mobile phones are shocking enough.
The radiation interfered with the pacemaker, and a life was almost lost while talking on the phone.
According to the Beijing Evening News Guangzhou Special News on the morning of August 24, a patient in Guangzhou with a permanent pacemaker was almost “killed” by a mobile phone.
The patient surnamed Wang went to the hospital to have a permanent pacemaker installed because of bradycardia the year before last. <Year> At 9 a.m. on August 24, after he borrowed a friend’s cell phone and made a call for a while, he suddenly felt his heart beat fast and slow, and his face changed drastically. His friend quickly escorted him to a nearby hospital for treatment. After examination by the doctor, it was determined that the radiation from the mobile phone was to blame. The doctor explained that electromagnetic radiation from radio electronic equipment can interfere with the control signals of medical equipment and instruments, disrupting their normal operation. When a patient with a pacemaker uses a mobile phone, pager or program-controlled telephone; or when he or she stays near a small mobile communication device such as a mobile phone or pager, his or her heart rate may slow down or stop, which may be life-threatening.
Therefore, patients with pacemakers must try to stay away from mobile communication devices and household appliances such as mobile phones, pagers, digital program-controlled phones, microwave ovens, and induction cookers. For the sake of safety, people with pacemakers can wear effective electromagnetic shielding clothing, such as shielding shirts, coats, vests, etc.

With the popularization of 5G technology, the application of mobile phone signal jammers in certain specific occasions has gradually increased. 5G signal jammer, as the name suggests, is a device specially used to shield 5G signals. Its main purpose is to prevent mobile phone signals from interfering with specific occasions and protect privacy and security. However, does the use of 5G signal jammers really bring safety protection, or is there more hidden dangers? This article will explore this issue from multiple aspects.

The functions and advantages of 5G signal jammers
First of all, the application of 5G signal jammers in certain specific situations has obvious advantages. In conference rooms, examination rooms, hospitals and other places, interference from mobile phone signals often causes a lot of inconvenience. For example, during important meetings, cell phone ringtones and information notifications not only interrupt the meeting process, but may also lead to the leakage of sensitive information. 5G signal jammer can effectively prevent these problems by blocking mobile phone signals, ensuring the smooth progress of meetings and the security of information.

In the examination room, the use of mobile phones may also lead to cheating. 5G signal jammers can effectively block candidates’ mobile phone signals, thereby preventing candidates from cheating through their mobile phones and ensuring the fairness of the exam. In addition, medical equipment in hospitals is very sensitive to wireless signals. 5G signal jammers can prevent mobile phone signals from interfering with the normal work of medical equipment and ensure patient safety.

Hidden dangers and risks of 5G signal jammers
5G signal jammers are not without pitfalls and risks. The first is the legal risk. Many countries and regions have strict regulations on the use of signal jammers. Using signal jammers without permission may violate the law and lead to legal disputes. Even in some countries, the use of signal jammers is completely illegal, so users need to fully understand local laws and regulations before use to avoid legal risks.

5G signal jammers may cause interference to other wireless devices. Although its main purpose is to block mobile phone signals, in actual operation, it is difficult to block only signals in specific frequency bands. Some wireless networks, Bluetooth devices, and even wireless surveillance equipment may also be affected by interference, causing these devices to not work properly. This will not only affect work and life, but may also bring safety hazards. For example, in an emergency, if the communication equipment of first responders is interfered with by a signal jammer, it may delay rescue time and cause serious consequences.

Faraday bags, no matter how effective they are, can only block radio communications. Cell phones can do malicious things that don’t involve using radios.

Modern mobile phones have become highly complex, with a large amount of delicate electronic hardware controlled almost entirely by microprocessors and software. While this is good news for functionality, it is bad news for security. For devices such as smartphones, the software controls almost everything about the phone, including how and when to turn the power on and off. In other words, the phone “has its own ideas”, including understanding “shutdown”.  signal jammer

The complex software systems of mobile phones are, to put it mildly, largely beyond the control of the user, especially in the case of smartphones equipped with microphones, cameras, location and environmental sensors, and communication links, and bugs in the software that controls them (or backdoors) and security vulnerabilities can have severe privacy implications.

It’s hard for people to reliably turn off software-based devices like smartphones completely, and this isn’t a persecuted fantasy, and some phone manufacturers even consider it a thoughtful feature. For example, some Apple iPhones continue to send Find My Device tracking beacons even when they are turned off. Even on devices that don’t “officially” support this feature, it’s possible for bad actors or malware to behave similarly, turning your phone into a permanent covert tracking device, regardless of whether you’ve turned it “off.” The risk of “false shutdown” is compounded by the non-removable batteries in many of the latest smartphones.

A well-known and popular method for those who want to ensure that their phone is isolated in certain scenarios and completely block the phone’s radio (including sending and receiving cell tower information, wifi, Bluetooth and NFC near-field communications, and GPS positioning signals) is to The phone was thrown into something called a “Faraday bag.”

The Faraday cage effect produced by Faraday bags can severely weaken or even block the radio signals of the devices inside, and is widely used to ensure that untrusted devices (such as mobile phones) can send and receive signals in unknowing or inappropriate scenarios. The principle of a Faraday cage is simple: it is just a solid conductive container that completely encloses the signal source, so that the RF voltage difference between any two points on the cage is always zero.

But in reality, building a Faraday cage system that works well in practice is not as simple as it seems. Any poorly sealed opening can create a junction that acts as an RF feed and significantly reduces attenuation efficiency.

Currently, some expensive (usually around a few hundred yuan) so-called commercial Faraday bags are hotly sold on e-commerce platforms. They are specially used for mobile phones and can be used to prevent commercial espionage or “pregnant women to protect themselves from radiation.” In addition, there are also a large number of claims on the Internet that claim to be able to temporarily shield The “local method” of mobile phone signal.

In today’s digital era, mobile phones have become a part of people’s lives. However, what follows is the frequent use of mobile phones at concerts, which may not only interfere with the experience of other audience members, but may also cause disruption to the artist’s performance. To address this challenge, an innovative solution has been developed – cell phone-free concerts. This article will introduce the concept and development of mobile phone-free concerts and analyze its impact on the audience experience and artist performance.  signal jammer

1. The concept and development history of mobile phone-free concerts
Cell phone-free concert is a new form of music performance that aims to create a concert environment without cell phone interference. In this kind of concert, the audience is asked to turn off or silence their mobile phones before entering the concert hall and put them in a designated storage place to ensure that the audience does not use their mobile phones during the concert. This concept stems from reflections on the traditional concert experience and concerns about the use of mobile phones in the digital age, aiming to create a more focused and pure music appreciation environment.
The development of cell phone-free concerts can be traced back to recent concerns about the negative impact of cell phone use at concerts. Some concert halls and artists are becoming aware of the disruption mobile phones can cause at concerts and are trying to take steps to limit audience cell phone use. As this awareness gradually deepens, mobile phone-free concerts are gradually gaining attention and popularity as an innovative solution.

2. The impact of mobile phone-free concerts on audience experience and artist performance
Cell phone-free concerts have a positive impact on the audience experience. By limiting the audience’s mobile phone use during the concert, mobile phone-free concerts create a more focused and pure music appreciation environment. The audience can listen to the music more attentively and be immersed in the beauty of the music without being disturbed by the use of mobile phones by the surrounding audience. This focused experience enhances the audience’s understanding and appreciation of the music, making the concert a more profound and meaningful experience.
Cell phone-free concerts have also had a positive impact on artist performance. Artists play an important role in concerts, conveying emotions and stories through music. However, if the audience keeps raising their mobile phones to take photos or videos during the performance, it will not only distract the artists, but may also affect their performance or even interrupt their playing. At cell phone-free concerts, artists can focus more on their performance without the distractions of cell phone use, thereby improving their performance level and the overall quality of the concert.
As an innovative form of music performance, mobile phone-free concerts not only create a more focused and pure music appreciation environment, enhance the audience’s listening experience, but also enhance the artist’s performance level and improve the overall quality of the concert. As people’s demand for concert experiences continues to increase, mobile phone-free concerts are expected to become a new trend in future music performances.

The power and number of channels of different base stations are different, and the distance between each base station and the prison is different. It is generally recommended that there should be no base stations within two to three hundred meters of the prison area where the mobile phone signal shielding system is installed. If there is a base station, the factors need to be carefully considered. The impact of being too close to the base station and having too strong a signal!  signal jammer

Influence from the layout of various buildings in the prison n
The scale, number of buildings, structure, size, floor height, etc. of each prison are different. The direction, power, terrain and other factors of the distribution of mobile phone base stations around each prison are also different. The strength of mobile phone signals transmitted from distant base stations is also different. No, the layout of each prison needs to be designed based on the actual site conditions!
Impact on other aspects
Even in the same environment, base station signals are affected by wind disturbance, air humidity, etc., which will cause fluctuations in signal field strength. In addition, there are also differences in field strength between indoor and outdoor spaces, the ground, building structures, materials, and metal objects that affect mobile phones. Blocking signals has very complex adverse effects.
Selection and technical indicators of shielding equipment n
Reasonably plan the selection of shielding equipment based on project funds. When selecting shielding equipment, attention should be paid to the size of its shielding radius (i.e., power), performance stability, life span, etc. The selection should also be based on the site environment. At the same time, consider using a mobile phone signal jammer with an adjustable radius (that is, adjustable power), or using a directional antenna to control the main emission area (direction) of the shielded signal.
Influence from human factors and normal machine wear n
Cell phone signal shielding systems are installed in prisons. Most of the shielding terminals are installed at relatively high or slightly concealed locations so that they are not detected by ordinary people. However, this does not necessarily prevent man-made damage. The impact of future human factors must be considered, including prison sentences. Prisoners (also resisted by prison guards) artificially damaged or cut off the power supply of the isolator.

Disabling security cameras can blur your features, but it doesn’t erase your presence. People viewing the surveillance know you are there, they just don’t know what you are doing. You can use LED lights to disable the camera at night, while infrared lasers are not restricted by day and night. Of course, you can also find a way to block the camera.

method 1
1 Use a very bright LED flashlight to shine directly on the camera. The brighter the flashlight, the better. You can choose a small portable flashlight. This method is only suitable for dark environments, so it can only be used when sneaking around at night or in a closed environment. X Research Source
2 Cover your face with lights. Position your camera and point the light directly at it. As long as you do it correctly, the lens will reflect, making it almost impossible to capture your appearance. X Research Source But be aware that the flashlight method is anything but subtle. A sudden bright light will let alert security guards know someone is coming. But this way you can at least use bright light to prevent the camera from capturing your face clearly.
3. Hold the flashlight steadily. Be careful not to let the light deviate from the camera, otherwise it will reveal your appearance. Be sure not to let the light shine on your face. Remember, this method requires quick and precise movements.  signal jammer
4. Install infrared LED lights on clothes. Another quick fix is to superglue a string of high-brightness light bulbs to a hat or bandana. If you want to make the effect even better, you can create an LED “mask” that will make your face look blurry. The light should be bright enough that the camera cannot capture your face clearly, but it should not block your view!

Method 2
1 Point the infrared laser directly at the camera. This method is more subtle than using a flashlight, but the action is more precise. If the laser deviates from the camera even for a moment, your face will be captured. Act quickly and efficiently to avoid detection. X Research Source This method works day or night. But the effect may be better at night. X Research Source You can use any standard laser pointer. Generally speaking, the stronger the laser, the better the results.
2 Be aware of the shortcomings of this approach. You’ll be photographed until you point the laser at the camera. If any obstruction appears between the laser and the camera, the camera will immediately resume functionality. Furthermore, it is difficult to judge the effectiveness of this approach. There’s no way of knowing exactly from your perspective whether the laser is pointed at the camera. Do not point the laser pointer at your own eyes. Otherwise you might blind yourself! X Relief Source US Occupational Safety and Health Administration can wear sunglasses to protect vision, but this does not ensure safety.
3 Watch for other cameras. Using this method requires focusing, which means that a laser beam can only disable one camera. Lasers are more discreet than LED lights or flashlights, but their effectiveness is limited. If you want several cameras to fail at the same time, you’ll need more laser pointers. You can ask a friend to help.

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.