Generally speaking, the frequency emitted by the signal jammer interferes with the frequency of the mobile phone to receive the base station. There is a competitive relationship between the jammer and the base station. If the transmission power of the signal jammer is lower than the power delivered by the base station to the mobile phone in the actual environment, then the shield The shielding device cannot be shielded, so effective shielding can be achieved only when the power of the signal shielding device is higher than the power delivered by the base station to the mobile phone.
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