Hello,
After building few Ubitx , my experiment regarding digital mode is to tap the audio prior the LM386 on the R70 resistor.? this option is providing a fix audio level and you dont need to use the volume potentiometer to adjust the level but the volume control from your computer. Ater some quick testing it is quit easyvto find out the suitable decoding level. i add a switch in order to separate the Mic from the digital audio input . in addition i add a 1:1 transformer and a 4,7nf capacitor in serial in order to isolate and adapt the input level for decoding.
73's Didier
F5NPV