Reason 1: The mobile phone value is not accurate, no signal but display full grid?
1. In the process of receiving and sending signals, the mobile phone has a baseband chip to encode and decode the signal. If the working efficiency of the chip is poor, the mobile phone signal will be weak.
2. Each mobile phone brand has no uniform regulations on the signal grid standard, and some brands will lower the value in order to highlight the ”signal is good”, so the mobile phone display signal is full, but the practical effect is poor.
Reason 2: Environmental impact signal propagation, resulting in “blind spots”.
Electromagnetic waves propagate in the direction controlled by the antenna, and obstacles that hinder the propagation of electromagnetic waves, such as metal shells of cars and trains, glass of buildings and other obstacles that can be penetrated, will attenuate the mobile phone signal. If it is in the basement or elevator, the area is not large or at the edge of the obstacle, the electromagnetic wave of the obstacle is difficult to penetrate or cannot diffract, the mobile phone may have no signal at all.
The standard to measure the strength of mobile phone Signal is called RSRP(Reference Signal Receiving Power). The unit of the signal is dBm, the range is -50dBm to -130dBm, and the smaller the absolute value, the stronger the signal.
Mobile phone with IOS system: Open the dialing keyboard of the mobile phone – enter *3001#12345#* – Click [Call] button – Click [serving CELL info] – Find [RSRP] and view the exact signal strength of the mobile phone.
Mobile phone with Android system 
pen the phone [Settings] – Click [About the phone] – click [Status Message] – click [Network] – Find [Signal strength] and view the exact value of the current signal strength of the phone.
Depending on the phone model and carrier, there may also be differences in operation. The above methods are for reference only.
lintratek is professional mobile phone signal amplifier manufacturer, welcome to contact us www.lintratek.com
Post time: Sep-25-2023