1. The distance of the surrounding base stations and the orientation of the antenna board on the base station;
2. Whether there is blocking and attenuation by buildings or other obstacles between the surrounding base station and the site;
3. The transmit power of each frequency band module of the mobile phone shielding instrument itself and whether it is output normally;
4. The erection height and erection position of the shielding instrument on site;
5. Use the site's own wall material, door and window opening size, and door and window orientation;
6. Whether a signal amplifier is installed inside the unit or in the corridor of the building;
