Six band pass filters were built to cover 10-80m bands on RX. Schematic utilizes Skywork solutions AS169 PHEMT GaAs SPDT switches, used in modern wirelless equipments. In order to perform individually “fine tune” a variable coil inductors are used. The module fully meets project CLICKLESS concept as there aren’t any mechanical switching components. MCP23008 serial controlled I/O expander is used to engage needed filter. The board has a provision for two optional filters.
Filters spectrum analyzer plots:
BAND PASS FILTERS