Well, it’s been a month since my last post. So, I should provide my SDR receiver update, complete with video.

Since mid-December, I have continued to flesh out my SDR project to control dual channel radios and record two channels of baseband for later diversity processing. Good news. My basic architecture is sound and I now have most of it working.

Writing a driver for the SDRplay RSPduo was challenging, until I figured out the revised API. I now have a testbed running with both Perseus and RSPduo, and record multiple channels. My next steps are to write a driver to play recorded files, and do diversity. You can see the overall architecture shown above.

Here is a short SDR project update video of my software in action. As you can see, I also added spectrum and signal displays. It doesn’t look pretty but is mainly working.

I need to work on calibrating the program to show signal strength properly, as well as do some debugging on a few areas, particularly the sample rate conversion. I have some built in signal generation and measurement tools to help with that.

I am very happy that all the DSP work is done in about 3-5 milliseconds, even at 1 megabyte sampling. The program only consumes around 4% CPU cycles, compared to the 25-30% on popular applications like PowerSDR Thetis and SDR Console.

SDR Receiver Update and More

I hope you had a good Christmas and New Year’s. We spent lots of time with family. My wife Hilda continues to recover slowly from her stroke last April. This is a very long process. Most of my time is as a caregiver, with a few spells of playing in the radio room.

For years, I have found writing software both intellectually stimulating and emotionally satisfying. That continues to be the case.

Best wishes for 2024.