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Month: September 2016

homebrew ssb receiver part 3 – receiver

For labor day weekend, I had some extra time, so I put together the direct conversion receiver from the first chapter of EMRFD. I made some small changes to the circuit and used the si5351/arduino combo as the vfo.

receiver_web

The receiver uses a NE602 as the mixer and an LM386 as the audio amp. I connected it to my 40 meter dipole, but I wasn’t hearing anything. After playing around with it for a while, I put together a simple rf amp and added it to the input and that seemed to help. I started picking up morse code immediately. I could hear some ssb, but it was so low I couldn’t make anything out.

rf_amp_schematic_web

rf_amp_web

I actually ended up putting together another version of this circuit on a breadboard as a test, but I still had the same low audio output whether I was using headphones or a small speaker.

I also had some intermittent problems with parasitic oscillations that I never figured out. Even with all of the problems, I’d say the project was a success since this is my first non-sdr receiver that I have ever built, owned, or even used and I was able to actually hear rf signals.

I think I will continue with my original plan and use the discrete audio amp from the second homebrew ssb receiver post and the same arduino vfo and build my own version of this receiver.

 

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