OptLowpass™ is a software program designed to quickly create transmitter output lowpass filters, particularly for use in the HF amateur radio bands. When you open the program, it will provide you with pre-made filters for each HF amateur band, using ideal parts values as specified in an article. You can also recall a prior design session, open a previously-saved design, or use the Design Wizard. The design page displays a schematic of the filter and a plot of the transmission and reflection responses.
