If the cable exceeds 100m, an amplifier must be installed, because the high-frequency coaxial cable that transmits the cable signal will attenuate the signal every 100m, and the signal level assigned to the user is 65db. If the transmission cable is 100m, 65dB-15db = 50db, the signal of 50db cannot meet the needs of watching TV normally. Therefore, when the cable exceeds 100m, the amplifier will be installed.
