Jammers sold in China will emit stronger radio waves than base stations
When checking whether the mobile phone is shielded, please note that you cannot only check the number of mobile phone data signal bars. Mobile phone jammers in Japan emit stronger radio waves than the base station, even though they are closer to the phone than the base station. Therefore, it is generally not recommended to conduct dynamic testing in the case of voice calls, but to conduct static data testing at each anchor point.
On the contrary, if the mobile phone can be connected, it means that it has exceeded the scope of the mobile phone blocker. In this case, I think a physical distance of about 5 meters is enough, especially when it is used on the bus. The truth is, you can't always keep close relationships with your family or friends, but no matter how close you are to your mobile phone, you can keep close relationships with them and communicate with them through your mobile phone.
Of course, there are also some devices, including shielding mobile GPS. It has an anti-interference capability, enabling the mobile phone to automatically adjust the signal strength to ensure abnormal voice calls. After the detection of multiple frequency bands, the short distance between mobile phone GPS shielding within a certain frequency range is selected as the reasonable shielding distance of mobile phone signal shielding in this area.
For expensive jamming devices, you can purchase one of these portable devices, especially if your primary goal is to stop people nearby. If it is shielded, it is judged that it still belongs to the category of shielded network phones. If you move from the unshielded area to the shielded area, you will usually walk a long distance into the area phone jammer before the phone is completely shielded.
You can try the mobile phone mixer. Because the cell number of the mobile phone data signal sometimes reports errors, it should be intermittent disconnection. To detect whether a location point is within the range of the mobile phone signal blocker, it needs to be kept on the mobile phone for more than 30 seconds to determine whether the mobile phone is shielded. You can try calling your local toll-free or fixed number. If you want to keep people quiet for a few minutes, such mobile GPS jammers can definitely be used. There are many kinds of mobile phone shields on the market. If you want to shield signals in a large area, you have to pay a lot of money to buy one of them.