Softrock V6.3 build: The RX Mixer Stage

The mixer stage acts like two traditional direct conversion mixers operating in tandem. It centres around U10, a SOIC-16 Dual 4:1 Mux/Demux Bus Switch. A 2-pin and 3-pin socket also needed to be installed along with three resisters. And for testing the stage, an 80/40m Band Pass Filter board also needed to be built.

Care had to be taken once more when soldering the tiny pins of U10 into position.


This is the underside of the PCB with U10 top middle.

Building the BPF was relatively simple, with the exception of winding the two coils; these take time and care but aren’t particularly difficult to do.


The 80/40m BPF board in place.

Testing went well. Current and voltage readings were as expected. The only test I was unable to carry out at this stage was to test it with Rocky, a SDR software package that shows a chunk of spectrum. This was due to my Linux laptop’s sound card not showing up in Rocky.

Next will be to build the TX Op Amps.



1 thought on “Softrock V6.3 build: The RX Mixer Stage

  1. Thanks for sharing Grant. I’m enjoying reading about the development of the kit as you progress through each stage. It’s very interesting to read about the challenges and how you deal with them. I’m looking forward to the next installment.
    Andrew (VK1AD)

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