In today's society, mobile phones have become an indispensable part of our daily life. With the continuous advancement of technology and the popularization of applications, mobile phones have brought great convenience to people. However, in various important national examinations, the use of mobile phones to cheat occurs from time to time. This has seriously affected the fairness of the test and the discipline of the test room. In order to maintain the discipline and fairness of the examination room, the state stipulates that the standardized examination room needs to be equipped with a full-band signal jammer. However, in actual use, after the jammer is turned on in some examination rooms, the mobile phone will still display the signal. The following will discuss why some mobile phones still show a signal.

First of all, if the mobile phone shows that there is a signal and the call can be made normally, for example, the call is clear and stable without any influence, then it means that the full-band signal jammer has not effectively shielded the mobile phone signal in the interference area. This situation may be due to the power of the full-band jammer used is too low, or there are base stations or indoor signal amplifiers near the location. In this case, it is recommended to use more high power jammers to meet the shielding requirements of the site.

Secondly, if the mobile phone shows that there is a signal, but the call quality is poor, it means that the shielding effect of the full-band signal jammer is in a critical state. This situation may be caused by the fluctuating signal strength of the base station, or some mobile phones with strong anti-interference ability. At this time, it is recommended to use a more stable full-band signal jammer to ensure the fairness and safety of the examination room.

The third situation is that the mobile phone shows that there is a signal, but in fact the signal is false. It cannot make normal calls, nor can it use data to surf the Internet. When making a call, the mobile phone will suddenly display no signal, or limit the service. This situation shows that the mobile phone is blocked by the full-band signal jammer, but before the shielding, the mobile phone has already received the signal, causing the signal displayed on the mobile phone to be a false signal. At this time, you can confirm whether it is blocked by conducting an interference test on the mobile phone.

In addition, you need to pay attention to the range that the full-band jammer can cover. Its shielding distance depends on the strength of the mobile phone signal where the unit is used. If the mobile phone signal is strong, the shielding distance of the full-band signal jammer will be shortened, and vice versa.

To sum up, the full-band signal jammer plays an important role in maintaining discipline and fairness in the examination room. However, its shielding effect is affected by many factors. It is recommended to choose a full-band jammer suitable for the actual situation to ensure the stability and reliability of its shielding effect. I hope this information can be helpful to the majority of candidates and staff.