bitx20 v3 build – mic amp

Last night I continued my work on the bitx 20 by adding the mic amp.


I put it in next to the af amp. I also added some rails to the side of the board. One for 12 volts, one for transmit, and one for receive.


I’ve got some sharpie markings between each section to try to keep things separate in case I need to troubleshoot anything later on.


I soldered on an electret microphone and the amp appears to work correctly. Here is a shot of the scope while I blew air at the mic.


Next step is the BFO. I still haven’t decided if I am going to build the analog/crystal bfo and vfo or if I will use a DDS chip for both. I went ahead and ordered some crystals, but at this point I am leaning towards an si5351.