SolidSDR: Web-based FlexRadio client (open source, cross-platform)

Something that would be useful for this use case would be a way to fine tune the frequency without a mouse .

I’m not sure what you mean. You should have the same control with a mouse or touch device. There was a bug that might have affected dragging a slice around in Chrome on touch devices, but it was fixed recently (v0.2.1 about 3 days ago). Is that what you were trying to do or something else?

Well, my problem seems to be that the app thinks chrome doesn't have audio permissions. When going to audio settings, it says audio permissions denied. Chrome has mic permissions but i don't see a setting other than that.

Apologies if you’ve already checked this. The only Android devices I have access to at the moment are old, so things might be a bit different. There are 2 different audio permissions… The OS level, where the OS allows Chrome to access the mic, and another where Chrome allows specific pages to access the mic. It sounds like the second one is what we’re missing.

It prompts you the first time you load the page but it’s easy to accidentally dismiss it, and Chrome will remember that forever. On my device there’s a little settings icon in the address bar, and tapping that shows Permissions with Microphone allowed. If it doesn’t say that, tap to change it. If that’s what you’re seeing too, then try a refresh or opening in a new tab and see if it picks it up.

If it still isn’t working can you share a screenshot of where you’re checking the Chrome mic permission?

On the fine tuning comment, I find it difficult to make small adjustments of say, a tuning step with the touch screen. I was thinking of something like the tuning wheel that Marcus has in the ios app or an up/down arrow that would move 1 step at a time.

Ah, yeah I get that. It's not too bad on a tablet, but on a phone it can be very fiddly, especially if your panadapter is zoomed way out. I usually just zoom in a bit until I can manage it 😀

Marcus' design is a good solution. I also thought about having buttons to nudge the slice like you suggested, or having up/down buttons for each digit on the slice frequency like what SDR++ does. We could also do something like doing a long press to enable "fine tuning mode" which takes a lot more movement to move the slice. I'll give it some thought over the weekend.

BTW, running the server on a pi 4. Runs great. No stuttering and the pa looks fine.

That’s great news! I did some testing on a Pi 3 and it was just barely able to do it, so I was hoping the Pi 4 would be a bit more capable. Pi 5 should have no problem at all. If you do end up having any performance issues, I wrote a wiki article with some suggestions specifically for the Pi.

https://github.com/daveisadork/solid-sdr/wiki/Raspberry-Pi#general-server-performance

I still need to figure out the correct assignments for DAX TX with Brave Browser and Ubuntu. I hear the tone on TX in the speaker, but it is not reaching the radio to TX.

OK, this was an adventure, but I think I found something that works. Modern Linux distros have virtual audio cable capabilities built in, so it's nice you don't need extra software like on Mac and Windows, but the downside is it's very difficult and confusing to configure. I tested this on Ubuntu, but it should work for any distro using pipewire.

Copy and paste these commands in the terminal:

#create the config directory
mkdir -p ~/.config/pipewire/pipewire.conf.d
#create the config file
touch ~/.config/pipewire/pipewire.conf.d/95-dax.conf
#edit the config file
open ~/.config/pipewire/pipewire.conf.d/95-dax.conf

You should have a text editor open with an empty file. If not, open the file with whatever text editor you like and paste this in:

context.modules = [
    # =================================================================
    # DAX TX: Virtual Transmit Bridge (Chromium + Firefox Compatible)
    # =================================================================
    # WSJT-X sends playback audio to the Sink ("DAX TX").
    # Chromium/Firefox record input modulation from the Source ("DAX TX Mic").
    { name = libpipewire-module-loopback
      args = {
          audio.position = [ FL FR ]
          capture.props = {
              media.class = "Audio/Sink"
              node.name = "dax_tx"
              node.description = "DAX TX"
          }
          playback.props = {
              media.class = "Audio/Source"
              node.name = "dax_tx_source"
              node.description = "DAX TX Mic" # True hardware-style input
          }
      }
    }

    # =================================================================
    # DAX RX 1: Virtual Receiver Channel 1
    # =================================================================
    # Browser SDR outputs VFO audio here. WSJT-X captures via Monitor.
    { name = libpipewire-module-loopback
      args = {
          audio.position = [ FL FR ]
          capture.props = {
              media.class = "Audio/Sink"
              node.name = "dax_rx1"
              node.description = "DAX RX 1"
          }
          playback.props = {
              media.class = "Stream/Output/Audio"
              node.name = "dax_rx1_playback"
              target.object = "none"
          }
      }
    }

    # =================================================================
    # DAX RX 2
    # =================================================================
    { name = libpipewire-module-loopback
      args = {
          audio.position = [ FL FR ]
          capture.props = {
              media.class = "Audio/Sink"
              node.name = "dax_rx2"
              node.description = "DAX RX 2"
          }
          playback.props = {
              media.class = "Stream/Output/Audio"
              node.name = "dax_rx2_playback"
              target.object = "none"
          }
      }
    }

    # =================================================================
    # DAX RX 3
    # =================================================================
    { name = libpipewire-module-loopback
      args = {
          audio.position = [ FL FR ]
          capture.props = {
              media.class = "Audio/Sink"
              node.name = "dax_rx3"
              node.description = "DAX RX 3"
          }
          playback.props = {
              media.class = "Stream/Output/Audio"
              node.name = "dax_rx3_playback"
              target.object = "none"
          }
      }
    }

    # =================================================================
    # DAX RX 4
    # =================================================================
    { name = libpipewire-module-loopback
      args = {
          audio.position = [ FL FR ]
          capture.props = {
              media.class = "Audio/Sink"
              node.name = "dax_rx4"
              node.description = "DAX RX 4"
          }
          playback.props = {
              media.class = "Stream/Output/Audio"
              node.name = "dax_rx4_playback"
              target.object = "none"
          }
      }
    }
]

Save the file and close the text editor. Then back at the terminal, run this command:

systemctl --user restart pipewire pipewire-pulse wireplumber

You might need to restart your browser and WSJT-X, but in both you should have new audio devices available.

In WSJT-X:

• Input: dax_rx1.monitor
• Output: dax_tx

Then in your browser in the DAX Settings dialog:

• DAX TX Input Device: DAX TX Mic
• DAX RX 1 Output Device: DAX RX 1

If it still isn't working, the system may have automatically muted some of the devices. This happened to me and I don't know why. I had to use pavucontrol to fix it, which is not installed by default. You can install it with:

sudo apt install pavucontrol

You can just run pavucontrol at the command line, or it shows up in the apps menu as "Volume Control"

Overall… kind of a frustrating process, but I did manage to get it working in the end. Good luck!