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by JKCalhoun 1002 days ago
Interesting. Also interested in getting into this. I have played with SDR, not FT8 though. Maybe you can point to a site that helped get you started with FT8.
1 comments
kunwon1 1002 days ago
I don't recall any specific how-to sites, I was all over a lot of them. There are three applications in my 'pipeline': SDR++ (a standard SDR client, any should work as long as you can choose your audio output device), WSJT-X [1], and GridTracker [2]

I'm on Linux, and I'm using PulseAudio. I need to route audio output from SDR++ to WSJT-X. I do this using these commands, which I found somewhere online that I can't recall:

    pacmd load-module module-null-sink sink_name=Virtual0
    pacmd update-sink-proplist Virtual0 device.description=Virtual0
    pacmd update-source-proplist Virtual0.monitor device.description=Virtual0
This creates a virtual device that I can select in the respective applications' options dialogs.

Connecting GridTracker to WSJT-X involves using the options dialogs in both programs, there is a UDP socket option, the details of which I don't immediately recall. My setup is different because I've written a one-off python script to log contacts for my own edification (sometimes I leave it running overnight to take advantage of the solar weather conditions)

WSJT-X is written by Joseph Hooton Taylor Jr. [3] He is an astrophysicist and Nobel laureate. It is well-documented software, but not very intuitive. Joe Taylor was also part of the team that developed the FT8 protocol. I recommend watching some videos about it or reading the documentation, as per your preference.

[1] https://wsjt.sourceforge.io/wsjtx.html [2] https://gridtracker.org/ [3] https://en.wikipedia.org/wiki/Joseph_Hooton_Taylor_Jr.?usesk...

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kunwon1 1002 days ago
Also, a few more items that I recall being difficult to figure out-

1. FT8 uses a standard frequency setting on each band. The presets are built-in to WSJT-X, or you can find them online. WSJT-X and your SDR client should be set to the same frequency.

2. To decode FT8, your radio should be in USB mode, and your system clock needs to be very accurate (By which I mean, you need NTP)

3. FT8 signals are practically invisible on a normal waterfall display

I had everything hooked up for a few days of head scratching before I realized that I hadn't setup NTP on my PC for reasons that escape me. As soon as my clock was synchronized, messages started pouring in. I have the most luck on the 20 and 40 meter bands.

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