I need to rescan again once per two days as one channel might be not in service.
is that due to the signal level is too weak?
do I need to add a amplifier?
cyril7: Hi, quality is the important one, its an indication of the Carrier to Noise ratio that intern indicates the achieveable Bit Error Rate. As long as there is enough signal to achieve good quality figures then all is good. You could deploy an amplifier (not recommended unless really needed) or install a higher gain antenna, or position it more appropriatly to achieve a higher signal level, but with good quality levels as you have it is unlikely to achieve anything.