The shielding effect of mobile phone jammer is related to the antenna?

At present, the mobile phone signal jammers on the market are low-power jammers about the size of routers in appearance. The single-channel power of this kind of mobile cell phone jammer ranges from 2-4W and has metal shell external antennas. It has a built-in antenna in a plastic case. How should I choose? In fact, the effect of the external antenna is not necessarily better than that of the built-in antenna. It also depends on whether the power of the single channel is the same. If the power is the same, the effect of the external antenna must be better. If the power is different, it will be another. Don't talk about it.

At present, the three major operators, China Mobile, China Unicom and China Telecom, have signal formats such as 2G, 3G, and 4G respectively. Among them, China Mobile and China Unicom are more clearly divided. Mobile communications basically use the 2G frequency. The frequency of Internet access is mainly based on 4G is mainly used, 3G is relatively less used, so we let go of the 2G frequency of China Mobile and China Unicom before the mobile phone jammer leaves the factory (mainly the GSM frequency band, there is 4G frequency in the DCS frequency band), and let it not work. , In this way, the mobile phone of China Unicom and China Unicom can only communicate but not surf the Internet.