It's exam season now. When schools conduct large-scale exams, they must use cell phone jammer in the examination room to prevent students from cheating by using mobile phones. Therefore, schools must install some mobile phone signal jammers near the classroom before the exam, but the school is buying them. When should I buy which type of shield? If you are the person responsible for purchasing at your school, here are a few things to keep in mind:
1. Is there a base station near the school? In the process of construction, we often find that customers tell us that the signal jammer is ineffective. 2G and 3G can be shielded, which means that the call signal can be shielded, but the 4G signal cannot be shielded. In fact, the power of each shield is different, generally 4G1 and 4G2, the power is about 2W, that is to say 33db. If there is a base station within 200 meters of the nearby, such a machine will also block the signal that is not 4G. It will also appear, customer feedback, no effect.
2, how to distinguish the frequency. The frequency of the shielding device is: 869~894MHz; 825~960MHz; 1805~1880MHz and 1900~1990MHz, etc. The working frequency bands are CDMA800, GSM900, DCS1800, and PCS1900. It can control the range of about 20 meters in diameter, using DC-DC converter input voltage, 5V output voltage.
3. The mobile phone signal (234G) of the call can be selectively shielded. If you only shield 23G or only 34G, this can be adjusted before leaving the factory. In addition, there are 2.4GWIFI, 5.8GWIFI, VHF, UHF and other frequency bands. How to understand it? That is to say, if you only want to block calls or WIFI, the manufacturer can focus on 2G3G on the host, and the cost will also come down.
4. Distinguish the power size. This is the easiest to fake, and it is also where manufacturers often fake. Because, to measure the actual power, a professional spectrum analyzer must be used. In the hands of ordinary customers, it is impossible to have such equipment. Therefore, it all depends on the professionalism of the customer's choice of equipment. Power size: The shield can generally be divided into low power, medium power, and high power, and the power is between 3W-100W.
These are the mistakes to avoid when buying a test room cell phone jammer. There are other points of attention, which we will discuss in detail in a later article.