In a recent study, when traditional test methods were used to understand shielding requirements in battery-operated portable wireless designs, several shortcomings were identified. Most of the test methods available today were developed to identify the materials that make up the EMI enclosure. However, there is currently no officially published test method to study the Shielding Effectiveness (SE) of an assembled shield on a portable wireless device PCB.

　　Add to that the recent boom in cell phone miniaturization. This means that high-frequency components are now crammed into very narrow spaces, which in turn reduces the size of the required printed circuit board (PCB).

　　For a conference room of about 100-300m2, usually, one or two low-power cell phone signal jammer are installed, which can basically meet the shielding effect of the whole conference room. In addition, the installation position should be determined according to the site environment. If the conference room is above the ceiling or has a movable ceiling, the shielding can be directly installed on the ceiling or ceiling. Or you can choose to install it on the conference table, corner, or wall of the venue. You can also use the built-in omnidirectional antenna. If you want to reduce the impact on the outside world, you can install it as a directional antenna.

　　If you want the cell phone jammer to cover a larger area, the simple and direct way is to use a more powerful jammer.

　　In the construction process of most standardized examination rooms, the project of installing mobile phone signal shields in examination rooms is included. However, some customers will always find that the shielding effect of the mobile phone signal shield in the test room is not ideal in the actual use process after it is turned on. If the factors of shielding equipment selection and poor working performance are excluded, how to install shielding equipment and how to choose the installation position of shielding equipment will become the main factors affecting the shielding effect.

　　Check the indoor mobile phone signal shielding device is generally installed in accordance with the original design drawings. The most common locations for shielding devices are the front and back of the blackboard or the top of the middle of the blackboard, the top corner of the front and back walls of the exam room, and the middle area on both sides of the classroom? ? Walls, beams in the middle of the classroom, etc. but some people for the sake of convenience, will shield device directly on the podium or hidden in the podium. This method was definitely not recommended, because hiding at a desk was not only bad for the heat dissipation of the cell phone signal shielding in the examination room, but if the table was made of metal, it was even worse for the signal transmission, directly affecting the shielding effect.

　　After the mobile phone shielding device is turned on, the effective coverage of shielding signals is usually tens of square meters to hundreds of square meters. However, due to the influence of the communication base station near the use scene or other factors, the shielding range may not reach the expected effect. At this time, people always want to use some methods to expand the coverage of blocked signals, so that the shielding effect of cell phone jammer can be greatly improved. Improve.

　　Most shielding devices mainly interfere with uplink signals. The reason is that the transmission power of the mobile phone is 23dbm, which is 2 watts. As long as the mobile phone (UE) is prevented from sending signals to the base station, the shielding function is basically realized, resulting in the UE and the base station being shielded. Signaling interaction is impossible. The main principle of the shielding instrument is to scramble a certain frequency band (most uplink frequency bands) and transmit useless signals.

　　But how much does this kind of home cell phone jammer cost?

　　First of all, how much is it gonna cost you? You can get the cheapest jammer for about $30 to $60(those only block certain types of signals -- like mobile signals). It's a bargain, right? On the other hand, they tend to work on the battery for only a short time and cover only a small area (about the size of a person's body).

　　There is no difference between the mobile phone signal blocker at home and the mobile phone signal blocker in the examination room in many places. For example, the shielded signal frequency bands are all frequency band shielding, that is to say, the mobile phone signals and WiFi signals of 5G can be shielded; The difference lies in the shielding range. The shielding range of the signal jammer in the examination room is generally about 100 square meters, covering the whole classroom examination room.

　　If you decide to buy one of the pro models, you must invest a serious amount of money behind it – at least 500$. On the upside, you don‘t have to worry about getting separate GPS jammers. More often than not, these models are able to block all sorts of signals including Cellular, Wi-Fi, GPS, Bluetooth, and Radio Communication.

　　As long as the domestic signal jammer can shield the children's room, this area is basically within 20 square meters. If the shield area is too large, may affect the normal use of mobile phones neighbors, easy to cause complaints. Therefore, in the choice of household mobile phone signal jammer, you can choose the lower power, so the price of the jammer will be lower.

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