RADEv2 (FreeDV v2) on FLEX-6000/8000/Aurora with RPI

Mike-VA3MW

This is a draft of a 'how to' to get the RADE image running the Applmage on a RPI and then have the new mode show up in SmartSDR.

I 'think' this all works, but I welcome input to the document.

This assumes you know how to have some basic knowledge of a RPI.

From:

https://github.com/drowe67/freedv-gui/blob/master/src/integrations/flex/README.md

Mike va3mw

✅ Running the FreeDV-FlexRadio AppImage on a Raspberry Pi

Version 2.1.0 or newer

This guide walks through:

1. Downloading the FreeDV-FlexRadio AppImage to a Raspberry Pi
2. Making it executable
3. Running the AppImage
4. Selecting a specific FlexRadio radio (optional)
5. Important limitations

This process works on:

• Raspberry Pi 4
• Raspberry Pi 400
• Raspberry Pi Compute Module 4 (CM4)

The AppImage requires a 64-bit Raspberry Pi OS.

An AppImage is a way to distribute Linux applications as one single, portable file that runs on almost any Linux system without installation.

Think of it like a Windows .EXE or macOS .APP, but for Linux.

What an AppImage Is

An AppImage is:

• A self-contained application
• Bundled with all libraries it needs
• Delivered as one executable file
• That you can run with no installation
• And no root/sudo required

1. Download the FreeDV-FlexRadio AppImage onto the Raspberry Pi

Open a terminal on your Raspberry Pi and download the AppImage using wget:

wget https://github.com/drowe67/freedv-gui/releases/download/v2.1.0/FreeDV-FlexRadio-2.1.0-aarch64.AppImage

If the wget fails, the file name might have changed. You'll have to manually edit it to match the file on the FREEDV website.

Verify that the file was downloaded:

ls -l FreeDV-FlexRadio-2.1.0-aarch64.AppImage

You should see the file listed.

Make the AppImage Executable

AppImages must be marked as executable before running.

chmod +x FreeDV-FlexRadio-2.1.0-aarch64.AppImage

3. Run the AppImage

You can now run FreeDV-FlexRadio directly from the terminal:

./FreeDV-FlexRadio-2.1.0-aarch64.AppImage

✔ Tips:

• If you are connected via SSH, consider running in a screen or tmux session so the program doesn’t close if your SSH session disconnects.
  

Example:

screen ./FreeDV-FlexRadio-2.1.0-aarch64.AppImage

4. Selecting Which FlexRadio to Connect To (Optional)

If you have multiple radios on the network, you can tell FreeDV exactly which one to use by setting the environment variable SSDR_RADIO_ADDRESS before launching.

Example (radio at 10.0.1.11):

SSDR_RADIO_ADDRESS=10.0.1.11 ./FreeDV-FlexRadio-2.1.0-aarch64.AppImage

This forces the AppImage to connect to that specific radio instead of auto-discovering all FlexRadios on the LAN.

5. Using FreeDV in SmartSDR

Once the AppImage is running and connected to your radio, FreeDV modes will appear in SmartSDR just like any other mode:

• FDVU
• FDVL
  

You can select them from the mode dropdown on a slice. Set up your Mic levels as you would on SSB.

⚠️ Important Limitations

1. DAX must be turned OFF

If DAX is enabled, no audio will transmit in FreeDV mode.

2. Only one FreeDV slice can be active per radio

You cannot run multiple simultaneous FreeDV slices on the same FlexRadio unit.

W1WRA

I am multitasking at the moment, but was able to get it up and running and was receiving stations. When I have some more time, I will test transmitting, etc. Thanks for the heads up.

Andrew VK5CV

G’day Mike,

What Pi are you running?

Is a Zero enough?

Andrew VK5CV

W1WRA

I'm using a PI 4 . The 4 is not using many resources, but I would guess a Zero might not be enough. You can always give it a shot though.

Mike-VA3MW

A pi3 should do it, but try with a Zero and see if it works. monitor the cpu load with htop.

Andrew VK5CV

Hi Mike,

Cool stuff.

Well it took a while with a new Win 11 desktop repeatedly interrupting the SD card burner for the PiOS Trixie. Old Win 10 PC to the rescue!
Up and running on a Pi Zero 2 W. Flex 6500. About 35% CPU over 4 cores an 5% memory.

Power out on transmit. SSDR Win on LAN. Will see what happens with iOS over WAN.

I will leave it running headless for now and wait for some signals to turn up. I assume it’s RADE 1 only.

Is there a script to make it run on power on or boot up?

I also assume the Pi needs to be on the radio LAN.

Andrew VK5CV

Andrew VK5CV

PS Pi Zero won’t do 64 bit.

Howard K7JNX

Is there any reason we couldn't have a corresponding appimage compiled to run under WSL running on the same Windows machine that runs SmartSDR?

Howard, K7JNX

Martin Bérubé

Has anyone tried to compile a x86_64 linux image from the source code?

Andrew VK5CV

The app stops when I turn off the radio.

Andrew VK5CV

Mike-VA3MW

Maybe that is because the App looses connection to the radio.

Andrew VK5CV

It should go back to monitoring for an active radio rather than terminating.

Andrew VK5CV

Hm? It’s doing what I just said now.
Once or twice there has been no power on TX that needed a cold boot to fix.

MultiFlex and multiple clients may be an issue. Keeping it simple for now.

Andrew VK5CV