using a simple Calf BandPass Filter LV2 plugin to clean up square wave, raspy, harsh sidetone QRQ CW

[Chuck aa0hw]

CALF STUDIO GEAR

https://calf-studio-gear.org/

ZAMGATE

https://www.zamaudio.com/

setup

FLdigi is keying the PI 4's usb serial port's RTS PINs the RTS pin is 'keying' a 555 square wave oscillator the 555 square wave oscillator audio output is connected to the pi's usb sound card's LINE INPUT (note there is some leak through, when not being keyed, of the 555 osc... to stop the leak, a simple GATE plugin is used... 'ZAMGATE'