Setting up your K3S for FT-8, JT-65 and other digital modes.
Use this link to K8ZT's instructions:
However, the instructions are missing a key setting in step 3! The Menu options MIC SEL must be set to 'LINE' and MIC+LIN must be set to 'OFF'. This turns the MIC GAIN knob into a LINE GAIN knob for adjusting the level of the K3S USB Sound Card. You can change the levels using the Windows USB Codec volume control and the LINE gain (i.e. MIC Gain) knob. The K3S display will show LINE X, where X is the level setting.
After the levels are set, you can set MIC SEL to Fp or Rp and MIC+LIN back to ON. The K3S will remember the USB Sound Card line setting. With MIC SEL set to Fp or Rp, the MIC gain control will have no effect on the USB Sound Card level!
Also - note that plugging something into the K3S Line In jack on the back panel will disable the K3S USB Sound Card.