"Why are we not able to receive or transmit digital signal well, even though there is strong RF signal?"

 -RF Meter with a strong signal, illustrated in the above diagram, within the red box-

The importance of Signal-to-Noise ratio (SNR)

-Four antenna for 'Quadversity' mode is able to improve Signal-to-Noise ratio (SNR)-

 -Monitoring Signal-to-Noise ratio (SNR) by the Channel Quality Meter-

-Considering switch to a new frequency or move the transmitter closer to the receiver antenna when Channel Quality Meter's reading is below "3"-

-The RF Meter have dropped, but the Channel Quality Meter shows that there is still a good signal if the reading is “3” or above-

-A stable RF environment-