The CM 7778HD has two switchable input choices. It has the option of VHF/UHF combined input or separate VHF and UHF inputs. The unit comes preset to combined input meaning the single input labeled "combined" will amplify both VHF and UHF signals. Connect the VHF/UHF antenna to the combined input of the CM 7778HD and both VHF and UHF signals will be amplified. If a seperate VHF and UHF antennas are in use set the input switch to seperate. Connect the VHF to the input labeled VHF and the UHF antenna to the input labeled UHF.
The CM 7778 gain control switch. It comes preset to the "Low" position. In strong signal areas leave the switch in the low position. In weaker signal areas set the gain switch to the "High" position.
To access the switch control panel of the Channel Master 7778HD preamplifier remove the 4 screws on the bottom of the preamplifier.
Switch #1. Combined or Separate input. Set to combined the preamplifier input labeled "combined" will amplify both VHF and UHF signals. Set to separate the preamplifier input labeled VHF will amplify VHF and the input labeled UHF will amplify UHF signals.
Switch #2. FM trap. Factory preset to the (IN) position. If the antenna in use will be used for FM reception set the switch to the (OUT) position.
Switch #3. (High) or (LOW) gain switch. In weaker signal areas when supplying multiple TV locations set this switch to the (H) position.