2020 December

Mobile phone shielding device selection guide for examination rooms

By the annual exam season, all parties have begun to prepare for the exam, and the invigilator has various tricks to prevent high-tech fraud. Among them, the shielding device used in the examination room is still an anti-fraud shielding device. However, Chengdu Saiyue Communication reminds that there are many types of shielding devices, and users should clarify their needs before purchasing them to avoid test room accidents due to poor shielding effects, and pay attention to the correctness of the method of use.

First of all, I want to clarify the place of use. Most schools use test room-type mobile phone shields that are suitable for long-term work and are durable. The second is how big are we in the shielded area? For example, if it is a room of 100 square meters or a venue of thousands of square meters, if the area is large, the power must be larger, and if the area is small, the shielding power must be considered small. Then there is which frequency bands need to be shielded. Are all China Mobile, China Unicom, Telecom and CDMA shielded? Still only need to shield part of the frequency band.

Phone Wifi signal jammer

At this time, we remind everyone that if you want to buy a suitable shielding device to achieve the effect, it depends on the method used. The main points are as follows:

1. It is recommended that the indoor shielding device be placed at a height of about 180cm-220cm above the ground, with a forward angle.

2. Whether there are obstructions (such as walls, metal products, etc.) between the wireless jammer and wireless communication equipment (mobile phones, etc.). The interference signal emitted by the jammer will be attenuated to different degrees after passing through the obstruction, please try to avoid it.

3. The weaker the wireless communication signal strength in the use environment, the stronger the theoretical shielding effect of the shielding device.

4. The farther the jammer application environment is from the signal tower, the stronger the theoretical shielding effect of the jammer.

Pros and cons of mobile phone signal jammer

Nowadays, with the rapid development of science and technology, traditional mobile phones are becoming more and more intelligent, and they have become an important communication tool indispensable in people’s daily work and life. Of course, the negative effects caused by mobile phones are also immeasurable. Negative impacts in special scenarios and specific times have become new leak channels and new criminal methods, posing a threat to the security of confidential information. Therefore, it is urgent to strengthen the management and standardized use of mobile phone signal blockers.

Mobile phone signal jammers are mainly used in places where no mobile phone communication is required, such as in various examinations, office premises of confidential departments, gas stations, etc. Because of their easy installation and simple use, more and more companies use signal blocker. And the equipment signal is always in a relatively static state, which will not interfere with other electrical equipment, and has played a certain role in some special places.

GPS signal jammer

The mobile phone signal jammer is also called mobile communication jammer, mobile phone signal isolator, conference security device, etc.The signal jammer transmits a strong signal consistent with the frequency of the mobile phone’s downlink frequency band, and is tuned with the signal sent by the base station to the mobile phone, so that the base station sends to the mobile phone The downlink signal is deformed and cannot be recognized by the mobile phone, which interrupts the connection between the mobile phone and the base station. Simply put, its main function is to make the phone unable to use normally. Its essence is to implement electromagnetic interference to the wireless network on which mobile phone communication depends, so that the mobile phone cannot access the network, and thus cannot receive information from the mobile network, and cannot send information through the network.

However, with the promotion of signal jammers, it has also brought some adverse effects. The wide use of signal jammers will interfere with the normal use of surrounding residents, causing residents to use mobile phones without signals. If the shielding range is shortened, there will be a lot of It is also difficult to control the blind angle and blind zone, the shielding edge distance, and the long-term coverage is wide, the power will be large, and the radiation generated will also affect the human body. Therefore, the quality of a mobile phone signal shielding device depends not only on the The effective shielding degree of mobile phone communication signals, but also whether the radiation pollution produced by it meets the national electromagnetic radiation protection standards

Especially in government agencies, once the staff of the agency accidentally leaked the content of their work, they could easily be stolen by illegal elements. This is a very dangerous thing for agencies and agencies. In order to prevent such incidents from happening, government agencies will be equipped with mobile phone signal jammers or mobile phone signal shielding cabinets to avoid leaks.

Many authoritative units began to use mobile phone signal jammers

When the mobile phone works, it is within a certain frequency range, the mobile phone and the base station are connected by radio waves, and the data and sound transmission are completed with a certain baud rate and modulation method. In view of this communication principle, the cell phone signal jammer scans from the low end frequency of the forward channel to the high end at a certain speed during the working process. This scanning speed can cause garbled interference in the message signal received by the mobile phone, and the mobile phone cannot detect the normal data sent from the base station, so that the mobile phone cannot establish a connection with the base station. The mobile phone is manifested as a search network, no signal, no service system and other phenomena.

desktop signal blocker

Common mobile phone signal jammers on the market have operating frequencies: 869~894MHz; 825~960MHz; 1805~1880MHz and 1900~1990MHz, etc. The operating frequency bands are CDMA800, GSM900, DCS1800, and PCS1900. It can control the range of about 40 meters in diameter, using DC-DC converter input voltage and 5V output voltage.

The emergence of mobile phone signal jammers has played a certain role in suppressing the increasingly serious “mobile phone noise pollution”. But as a mobile communication interference device, will the electromagnetic radiation generated by the A topic of concern. At the same time, during the installation and use of mobile phone shielding equipment, due to the greater autonomy and randomness in terms of the number of installed units, transmission power, coverage, and radiation control, some places require effective interference and The shielding effect is maximized, even blindly introducing high-power mobile phones to interfere with the installation and use of shielding equipment. The impact and damage to the human body cannot but be worrying.

As another product of human beings, the “mobile phone signal jammer”, while shielding mobile phone signals and ensuring information security, it will definitely bring a certain negative impact. However, when we look at the problem, we should see the main contradiction. Just as we did not stop using a kitchen knife because it cuts vegetables, we will not reject a “mobile phone signal jammer” because it may cause harmful radiation to the human body. After all, the “mobile phone jammer” guarantees information security and contributes to social stability is its main contribution. The most important thing is that it brings security to places with high safety factors such as prisons, detention centers, and major conferences.

As far as the quality of the mobile phone signal shielding system is concerned, judging by the current level of scientific understanding, there is no security problem. The reason for this is mainly based on the following two reasons:

First, from a technical point of view, although the mobile phone signal shielding system is a new technology product, it should be said that it has been developed more mature in technology, so it has high security. According to the test report of the authoritative testing organization, the qualified mobile phone signal shielding system has low radiation, and because it is usually installed in high places, it has no adverse effects on human health.

Second, from a practical level, many authoritative units in China have begun to use mobile phone signal shielding systems. For example, in 2004, in order to maintain the solemn atmosphere of the memorial hall and meet its special confidentiality requirements, the Chairman Mao Memorial Hall Administration installed a mobile phone signal shielding system produced by Shanghai Jike Electronics Co., Ltd. in the memorial hall. After actual use and testing , The Memorial Hall Administration believes that the products produced by Jike Company meet its requirements in all aspects including safety and aesthetics. I think this should be a very convincing case. In addition, according to the information collected by the author, as a leader in the mobile phone signal shielding system industry, the products produced by Shanghai Jike Electronics Co., Ltd. are used in the prisons of the judicial departments and the detention centers of the public security departments. All of them are used, and the feedback after use is believed to be a proof of immortality.

Is the cell phone signal jammer harmful?

It is very interesting that the mobile phone, which is the “enemy” of the cell phone signal jammer, has also caused controversy about security at the beginning of its appearance. However, as people gradually understand the mobile phone, people finally accepted the mobile phone, and In less than ten years, mobile phones have become an indispensable necessity in our lives, and even because of the popularity of mobile phones, a new generation has been born: the thumb generation. This shows the popularity of mobile phones. In the history of human knowledge, the development of one aspect of contradictory things can predict the future of another aspect. Such examples are not uncommon. I think the development of mobile phones as the “enemy” of the mobile phone signal shielding system may be It can provide a blueprint for us to predict the industry picture of the mobile phone signal shielding system.

5G telephone signal blocker

Finally, I want to tell a true story: when China was building the Daya Bay Nuclear Power Plant in Guangzhou in the 1990s, Hong Kong citizens were very resistant to the project because of the safety of nuclear power. In order to dispel the doubts of Hong Kong citizens, the chief engineer of the project I joked that kitchen knives are also problematic in safety. Kitchen knives can cut fingers inadvertently, and even be used as murder weapons by wicked people. But this does not prevent us from using kitchen knives and does not prevent China from becoming a great food country, because as long as we do our best, we can Can prevent these things from happening. This very superb joke at the time greatly eased the resistance of Hong Kong people to the Daya Bay Nuclear Power Plant and made a small contribution to the smooth start of the nuclear power project.

There is no doubt that technology is a double-edged sword. We all know that mobile phone signal jammers have a certain amount of radiation. In the current situation that there is no authority to define how much this radiation can harm people, what we should do is to start from a people-oriented perspective as much as possible and make good use of technology. Advantages, control and reduction of the disadvantages of science and technology, on the premise of ensuring the safety and health of people, to decide whether to widely use in daily life, not for the uncivilized behavior of a few people, and ignore or even affect the interests of most people .

Cheap GPS jammers pose a major threat to drones

Jammers that can be bought for as little as $ 50 threaten commercial drones, but options exist.

With the rotors buzzing and the airframes racing through the air, drones can be very dangerous if flights don’t go as planned. Much has been gnawed about the FAA’s measured approach to implementing commercial drone guidelines, but the fact is there are real dangers, even from bad actors using inexpensive GPS jammer.

phone signal jammer

GPS signal jamming technology is evolving, decreasing in size and cost. These days jammers can be bought online for as little as $ 50. Jamming has long been a threat to military assets and is becoming a commercial problem today as commercial drone shipments become a reality and attacks become ubiquitous around the world. This threat now affects trade, law enforcement, and defense drones on critical missions.

During a choreographed light show in Hong Kong in 2018, 46 drones fell from the sky due to a jamming device. The resulting property damage and loss of hardware is estimated to cost an estimated HK $ 1 million. Almost all drones have security protocols that can be used to send them home or to a safe landing site in the event of a disruption. However, these functions were found to be ineffective at the Hong Kong show.

“These are professional-grade drones already built with technology that will guide them back to the launch site,” Anthony Lau Chun-hon, director of the events committee, told the South China Morning Post. “But the signals were so strong that many of them just fell out of thin air.”

Drones and their services are decidedly dependent on GPS signals. Although the drone may have backup methods (INS / OPS), GPS references are still required for positioning, navigation and stabilization. GPS attacks are therefore the easiest way to shut down a drone and potentially cause harm to life and property.

The good news is that solutions for drones are arriving with commercial quality and coming straight from the defense sector. One comes from a company called infiniDome, which makes a device called a GPSdome that is built into a drone’s GNSS receivers and uses a unique interference filter system that combines the patterns of two omnidirectional antennas. GPSdome analyzes the interference signal in real time and feeds its properties into infiniDome’s proprietary algorithm to filter and reject attacking RF interference, so that the UAS continues to rely on GPS signals during a jamming attack. If an interference signal is detected, the GPSdome notifies the operator of possible signal interference.

Easy Aerial, a leading provider of autonomous, drone-based surveillance solutions for commercial, government and defense applications, recently added GPSdome to its range of autonomous unmanned aerial systems for military use.

“We chose GPSdome because it was a proven solution that was a perfect fit for the various missions our customers routinely fly in some of the most inhospitable and hostile environments in the world,” said Ido Gur, Co-Founder and CEO of Easy Aerial. “While our systems have multiple redundancies on board, GPS signals for maintaining position, navigation and timing accuracy are critical to ensure uninterrupted operation.”

This type of lightweight, small form factor, low power shielding technology is a critical step towards widespread adoption of commercial drones. Other companies like Sepentrio also take GPS interference in drone applications with integrated sensor solutions seriously.

It is certain that the problem of GPS interference and spoofing will receive more attention in the coming days. Fortunately, developers seem to be beginning to see tools that they can use to counter the growing threat.

Install Cell Phone Jammers To Avoid Road Accidents

This is a question you should consider today. You may ask me: why should I worry about this? In response to your question, I would like to say that despite the fact that it doesn’t seem like a problem (for example, in relation to texting while driving), this topic is more and more popular these days. That is why I ask you to think deeply and consider various options. You also provide cell phone signal jammer to choose from.

Powerful signal jammer device

There is no law against texting while walking. But a town called Fort Lee in New Jersey almost passed such a law. Ultimately, the law was not approved and a few state walking safety programs were launched in March, as two fatal pedestrian crashes occurred in Fort Lee within 24 hours of February this year. . In addition, 117 pedestrians were fined for using crosswalks without using or using a cell phone.

Whether you are driving or crossing the road (or using a crosswalk), texting while driving or walking will not only put your life at risk, but the lives of others around you as well. For example, you text when going to the crosswalk, but you don’t see red lights and green cars. You start to cross the road, or you are hit by a car (especially if the driver is also texting and can’t see you), or the driver will apply hard braking and be hit by a car driving behind them. Or realize that he won’t be able to stop in time and is ready to stop his car from hitting you, he will turn to the sidewalk to take more time to rest. And no one knows how it will end … I suggest installing cell phone jammer around traffic lights, in order to eliminate the danger of looking at the phone.

To solve this problem, different countries use different methods. For example, in London, for pedestrians texting while walking, they would see loads on the poles, and when they hit the poles, they wouldn’t take much damage. Does that sound funny? Yep, it’s fun watching someone in that situation, but when you hit that post with your head, it’s definitely not that fun. However, for all pedestrians, including you, there is another option – you can prevent texting while walking and make your life and that of many people around you safer.

What should I do if I am tracked by cell phone signals?

China now has a lot of cell phone signal jammer, but what would happen if China did not have a mobile phone signal booster? Most of the mobile phone signal booster technology is not up to standard, resulting in a serious decline in the overall signal quality of many urban villages. It is because of this type of equipment that the mobile phone signal amplifier products are notorious. The actual data interferes with the base station and affects the neighbors’ equipment. It is just that people have a habit of doing well. If there is a problem, it will be spread.

Although the mobile phone signal amplifier has produced many negative effects, the positive effects are even greater. In my basement, there is no signal to solve by myself. Your own company has just been renovated, and you can solve it yourself if the signal is not enough. Any environment where the signal cannot be resolved in time can be resolved with an amplifier.

Most of the mobile phone signal amplifier technology is not up to standard, leading to a serious decline in the overall signal quality of many urban villages now. It is because of this type of equipment that the mobile phone signal amplifier product is notorious for oceans. The actual data interferes with the base station and affects the neighbors’ equipment. It is just that people have a habit of doing well. If there is a problem, it will be spread.

Overview of wireless signal shielding principle of signal jammer

Let’s take a look at the overview of the principle of wireless signal shielding of signal jammers.

The working principle of mobile communication is that within a certain frequency range, wireless devices (mobile phones, etc.) communicate with the base station through radio waves, and complete data and sound transmission with a certain baud rate and modulation method. When the mobile phone communicates, it communicates with the base station through the uplink frequency, and then transfers the signal to the mobile service switching center to realize the call. In the standby state, the mobile phone communicates with the base station through the broadcast control channel. Once there is a call demand, it will be allocated to the mobile phone service channel according to the specific conditions of the channel near the terminal through the request, so that the mobile phone can jump to the service channel to realize the call and data transmission . At the same time, wireless communication must ensure a sufficient signal-to-noise ratio to effectively receive and complete communication.

desktop signal blocker

According to the above working principle, the cell phone signal jammer is generally composed of power supply, electronic scanning control unit, segmented radio frequency module unit, amplifier unit, transmitting antenna unit and other parts. The scanning signal generated by the signal generator passes the inverter, enters the oscillator and modulates it to the mobile communication working frequency band, and then is amplified by the power amplifier and the voltage regulator tube controls the power. The amplified frequency sweep signal is transmitted into the air in the form of radio waves. Because the frequency sweep signal forms garbled interference in the message signal received by the mobile phone (increasing the proportion of noise and noise signals to the device threshold), the mobile phone cannot receive the normal data sent by the base station, so that the mobile phone cannot establish a normal connection with the base station, thereby causing the mobile phone to disconnect Base station communication network. The mobile phone exhibits the phenomenon of no signal and no service system in the search network, which achieves the blocking effect. The mobile phone signal jammers produced by our company can achieve super high shielding effect, safe and simple.

The interference power of the jammer is fixed, and the shielding radius of the unblocked space is determined by the path attenuation and the signal level of the receiving base station. To realize interference from mobile phone signal jammers to mobile networks, it is necessary to ensure that the signal field emitted by the jammer is stronger than that of the mobile signal in the interference area. The closer the interference location is to the base station, the stronger the field strength and the smaller the effective interference area. , The farther the interference location is from the base station, the weaker the field strength and the larger the effective interference area.

It can be seen that within a certain transmit power, the interference range depends on the field strength in the interference area. No matter how powerful the jammer is, as long as the transmit power is a fixed value, as the distance increases, the interference signal strength will gradually attenuate and lose Interference ability. The following table shows the comparison table of distance and path attenuation. Then the output channel power of the jammer, the base station signal level, and the coverage line gain can determine the theoretical coverage radius with reference value.

Principle of signal isolator

In the industrial production process, a variety of instruments and meters are used in the monitoring and control of the generation process, which will generate a variety of signals: both faint small signals of millivolt level and tens of volts Large signals, even strong signals up to thousands of volts and hundreds of amperes; there are DC low-frequency signals, high-frequency or pulse spike signals; and these signals have to go through the process of mutual transmission and transmission, so how to ensure these signals In particular, the non-distortion of analog signals during transmission will become a problem that must be solved in system debugging.

Specifically, only when the analog signal transmission between the control device and the sensors and actuators distributed in the field is fault-free and undistorted, can the process control be safe and reliable. Especially low-power analog signals are affected by various external interference signals when they are transmitted in an industrial environment with high interference, and they need a reliable transmission channel. Daily work experience shows that due to equipment requirements, analog signals must be handled and transmitted carefully. However, the measurement and control parameters transmitted in the form of analog signals between the field and the control layer are often in a harsh industrial environment in the transmission project, which is likely to cause distortion of these signals.

smartphone signal blocker

Second, the principle of signal jammer

At present, the signal isolator (converter) is mainly divided into several kinds of isolation methods: transformer isolation method, photoelectric isolation method and transformer and photoelectric joint isolation method.

Signal isolators have a history of more than 40 years. Early signal isolators used transformer isolation. Its characteristics are: stable performance, long life, strong load capacity, high isolation strength, but the circuit is complex, and the manufacturing process requires higher.

With the development of electronic technology, in recent years, optoelectronic isolators produced by optical couplers have gradually appeared. Its characteristics are: stable performance, strong anti-interference ability, simple wiring and low cost, but compared to The transformer isolation method has a slightly shorter life.

In some occasions where the interference is large and the process requirements are high, the signal isolator of the combination of transformer and photoelectricity appears, and its isolation ability, resistance to unlimited radio frequency and electromagnetic interference is stronger.

Can the mobile phone signal jammer interfere with the base station’s signal?

Cell phone jammers are familiar to everyone, but everyone who has taken a large-scale exam has seen them and put them at the entrance of the exam room. This is not a malicious blocking signal. On the contrary, this is to maintain fairness and provide a fair environment for candidates. However, most of the time, some people doubt whether it will affect the signal radiation of the base station, so that there is no signal in an area.

With the progress of society and the development of high technology, people’s standards are getting higher and higher. Nowadays, mobile phones have become a habit of adults and children. For elementary and middle school students, it is more important to influence what they say. Playing with mobile phones for a long time may affect their eyesight, and more seriously, neglect their studies.

Since the advent of cell phone signal jammer, they have been trusted by examination rooms, schools, prisons and other units. In fact, mobile phone signal jammers are no longer a new thing abroad, and have begun to be sold in the domestic market in recent years. The cell phone signal blocker only interferes with lower cell phone signals, so it will not affect mobile base stations and other electronic devices. Now many elementary and middle school students are holding mobile phones one by one, some are addicted to games, some are addicted to novels, etc. It is even more dangerous for school exams. Baidu has all the answers. If everyone used their mobile phones to plagiarize during the exam, it would violate the purpose and significance of the exam!

Desktop high-power electronic jammer

In the face of mobile phone signal shielding, we should treat it rationally and scientifically. The working principle of the mobile phone signal blocker is to send out a specific signal to wake up, block or interfere with the signal between the mobile phone and the base station, so that the mobile phone has no signal or cannot find the network service, and the mobile phone will send and receive text messages. Unable to recognize the original text message.

In fact, signal jammers generally do not affect the signal of the base station, so there is no need to worry, and no one will consider interfering with other people’s signals.

The mobile phone jammer scans from the low end of the forward channel to the high end at a certain speed during the working process. This scanning speed can cause garbled interference in the message signal received by the mobile phone, causing the mobile phone to fail to detect the normal microwave signal data sent from the base station. In a certain range, the mobile phone cannot be connected to the base station, and the mobile phone appears as a search network, no signal, no service system, etc., and thus cannot be used. The purpose of disabling the mobile phone is achieved. Its operating frequency is: 869~94MHz; 825~ 960MHz; 1805~1880MHz and 1900~l990MHz, etc. The operating frequency bands are CDMA800, GSM900, DCS1800, PCS1900. When the mobile phone leaves the range of the jammer, it can be fully restored to normal use. The electrical signal emitted by the mobile phone jammer is undoubtedly an electromagnetic signal, but this kind of jammer will never have any equipment to communicate with it, and it will never form a sudden change signal. In other words, this signal will always be in a relatively static state. , It will not interfere with other electrical equipment, and it is harmless to the human body.