Additional Amplification To Compensate For CW Filter Insertion
In my Progressive Receiver I use two crystal filters. The 2.1kHz SSB filter is always kept in line while the 500Hz CW filter is switched in or out depending upon my listening preferences. Stacking the filters in this manner inserts some loss into the circuit. Therefore, additional IF amplification is also switched into the line when the CW filter is active. Note: This circuit was designed for my 200 ohm impedance filters. This circuit is not part of the original design for the Progressive, and was designed by "Mike," W3TS.