Mistakes to avoid when buying an exam room signal jammer
In the case of large-scale examinations, colleges must use test room shields so as to prevent students from cheating on mobile phones. Therefore, colleges and universities need to assemble a part of the test room cell phone jammer device around the classroom before the exam. , But which model and specification of signal jammer should be bought when colleges and universities buy it? If you are the person who undertakes the purchase of the college, pay special attention to the following aspects:
1. Are there communication base stations around the college? In the process of engineering construction, we often find that customers respond to us that the signal blocker has no practical effect. 2G and 3G can be intercepted. In other words, the signal of voice call can be intercepted, but the signal of 4G cannot be shielded. In fact, the output power of each signal jammer is different, usually 4G1 and 4G2, the output power is about 2W, in other words 33db. If there is a communication base station within 200 meters of the surrounding area, such machinery and equipment will not intercept 4G signals. It will happen, and the customer reacts with no actual effect.
2. How to distinguish frequency. The effective frequency of the signal jammer is: 869—894 MHz; 825—960 MHz; 1805—1880 MHz and 1900—1990 MHz. The effective frequency bands are CDMA800, GSM900, DCS1800, and PCS1900. It can handle a range of about 20 meters in diameter, and use a DC-DC converter to enter the voltage, and the output voltage is 5V.
3. Alternative interception of mobile phone signals (2/3/4G) for voice calls. If you only intercept 2/3G or only 3/4G, 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? In other words, if you only want to intercept voice calls or WIFI, the manufacturer can mainly push 2G and 3G on the host, so the cost will also come out.
4. To distinguish the size of the output power. This is the easiest to cheat, and it is also a place where manufacturers often cheat. Since, to measure the true output power, a professional spectrum analyzer must be used. Normal customers are unlikely to have such machinery and equipment. Therefore, this thoroughness depends on the professionalism of the customer's selection of machinery and equipment. The size of the output power: signal jammers can usually be divided into small output power, medium output power, high power, and the output power is between 3W-100W.
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