AetherSDR

A Linux-native client for FlexRadio Systems transceivers

AetherSDR brings FlexRadio operation to Linux without Wine or virtual machines. Built from the ground up with Qt6 and C++20, it speaks the SmartSDR protocol natively and aims to replicate the full SmartSDR experience.

Current version: 26.7.1 — CalVer (YY.M.patch[.hotfix]). | Download | Discussions | What's New

Cross-platform downloads available: Linux AppImage, macOS universal DMG, Windows installer and portable ZIP. Linux is the primary supported platform. macOS and Windows builds are provided as a courtesy.

Native. Open. Yours.

Highlights

• GPU-accelerated spectrum & waterfall — QRhi rendering on the GPU (OpenGL/Metal/D3D11) with a per-pixel FFT trace at up to 60 fps, an optional 3D stacked-trace spectrum mode (perspective FFT history, floor-anchored ridges), ~71% CPU reduction over CPU paint, GPU-composited slice flags, and multi-GPU adapter selection
• Multi-slice & multi-panadapter — colour-coded VFO overlays, independent TX assignment, diversity/ESC beamforming; up to 8 detachable pans with native VITA-49 waterfall tiles, with selectable S-meter / SmartMTR meter views per flag
• KiwiSDR public-receiver browser — find and connect to public KiwiSDR receivers worldwide through an API-policy-aware directory (diversity receive with receive-only TX inhibit)
• Aetherial Audio Channel Strip — a unified RX and TX DSP suite (gate, EQ, compressor, de-esser, tube, AetherVoice exciter, reverb, brickwall limiter) with a preset library and a per-side scope
• Six client-side noise-reduction engines — NR2 (spectral), RN2 (RNNoise), NR4 (libspecbleach), DFNR (DeepFilterNet3), BNR (NVIDIA GPU AI — the Maxine denoiser in-process on a local NVIDIA RTX/GeForce GPU, Linux + Windows; see docs/nvidia-bnr.md), and MNR (macOS)
• DAX virtual audio + IQ — 4 RX + 1 TX channels and raw I/Q at 24–192 kHz for WSJT-X / fldigi / VARA / JS8Call, plus a per-slice WFM demodulator for satellite data
• AetherModem packet radio — KISS-over-TCP TNC, connected-mode AX.25 BBS, a personal mailbox, and an APRS client (station map, GPS beacon, messaging) with a Direwolf-derived VHF demodulator
• AetherSweep — in-panadapter SWR analyzer with log scale, threshold-band shading, and interpolated bandwidth at SWR ≤ 1.5 / 2.0
• SpotHub — DX Cluster, RBN, WSJT-X, POTA, and FreeDV Reporter spots with auto-mode switch
• CW operator suite — real-time Morse decoder, MIDI/keyboard straight-key & iambic paddles with full QSK, optional Quindar tones
• FreeDV RADE — AI digital-voice codec with a client-side neural encoder/decoder
• SmartLink remote + TCI v2.0 server — Auth0/TLS WAN operation, and CAT + audio + IQ + CW + spots over a single TCI WebSocket
• Broad hardware control — rigctld + virtual-serial CAT, MIDI mapping, the FlexControl knob, serial PTT/CW keying, and Multi-Flex operation alongside SmartSDR/Maestro

How AetherSDR Is Built

AetherSDR is developed using an AI-augmented open-source workflow:

• Project lead (Jeremy KK7GWY) + a core contributor team working primarily through Claude Code and a mix of AI development tools — every commit goes through the merge gate; nothing reaches main without human review
• AetherClaude orchestrator bot auto-triages incoming issues, drafts implementation plans, and produces PRs for issues labelled aetherclaude-eligible
• Contributors use a mix of AI tools (Codex, Copilot, Cursor, Gemini, Aider) — the project's Constitution (14 principles, structured per Cisco's Foundry Constitution spec) codifies the conventions every contributor and every AI tool follows
• Branch protection enforces signed commits, CI green, and CODEOWNERS review — every change goes through the same gate regardless of which AI tool (or human) produced it
• At active pace: ~50 PRs per week, ~15,000–30,000 lifetime downloads, ≥6 distinct AI tools touching the codebase

See AGENTS.md for the canonical project guide that every AI assistant reads first, and CONSTITUTION.md for the principles that gate the contribution model.

The full list of code contributors is auto-generated from GitHub commit attribution — see the Contributors graph.

Supported Hardware

Works with any FlexRadio transceiver, including:

• FLEX-6000 series: FLEX-6300, FLEX-6400, FLEX-6400M, FLEX-6500, FLEX-6600, FLEX-6600M, FLEX-6700
• FLEX-8000 series: FLEX-8400, FLEX-8400M, FLEX-8600, FLEX-8600M
• Aurora series: AU-510, AU-510M, AU-520, AU-520M
• ML-, CL-, and RT-series devices

Supported external devices include the 4O3A/FlexRadio PGXL (Power Genius XL) power amplifier and TGXL (Tuner Genius XL) antenna tuner.

Active test target is FLEX-8600 firmware 4.2.18 (SmartSDR protocol v1.4.0.0); earlier 4.x firmware works; v3.x is unsupported.

Tested Controller Devices

AetherSDR supports external station-control hardware through USB serial, USB HID, MIDI, Stream Deck/StreamController plugins, and generic USB-serial adapters:

• FlexRadio FlexControl USB tuning knob
• Icom RC-28 USB remote encoder
• Griffin PowerMate USB knob
• Contour ShuttleXpress and ShuttlePro v2 jog controllers
• MIDI controllers with learn mode, profiles, and relative-encoder support
• Elgato Stream Deck devices through the bundled macOS/Windows Stream Deck plugin
• Stream Deck devices on Linux through the bundled StreamController plugin
• USB-serial PTT/CW interfaces for foot switches, straight keys, iambic paddles, amplifier keying lines, and external sequencers

Download

Pre-built binaries are available from Releases:

Building from Source

Dependencies

Install all dependencies for a full-featured build. Optional packages are noted — the build succeeds without them but the corresponding features are disabled.

# Arch / CachyOS / Manjaro
sudo pacman -S qt6-base qt6-multimedia qt6-websockets qt6-serialport \
  qt6-shadertools cmake ninja pkgconf autoconf automake libtool \
  fftw portaudio hidapi qtkeychain-qt6

# Ubuntu 24.04+ / Debian / Linux Mint
sudo apt install qt6-base-dev qt6-base-private-dev qt6-multimedia-dev \
  qt6-websockets-dev qt6-serialport-dev qt6-shader-baker qt6-shadertools-dev \
  cmake ninja-build pkg-config autoconf automake libtool \
  libfftw3-dev portaudio19-dev libhidapi-dev qtkeychain-qt6-dev \
  libxkbcommon-dev libopengl0 \
  gstreamer1.0-pulseaudio gstreamer1.0-plugins-base

# Fedora
sudo dnf install qt6-qtbase-devel qt6-qtbase-private-devel qt6-qtmultimedia-devel \
  qt6-qtwebsockets-devel qt6-qtserialport-devel qt6-qtshadertools-devel \
  cmake ninja-build autoconf automake libtool \
  fftw3-devel portaudio-devel hidapi-devel qtkeychain-qt6-devel

# macOS (Homebrew)
brew install qt@6 ninja cmake pkgconf autoconf automake libtool \
  fftw portaudio hidapi qtkeychain

What each dependency enables

Linux Mint / Ubuntu note: If PC audio devices show as "Dummy Output", install gstreamer1.0-pulseaudio. For PipeWire systems, also install gstreamer1.0-pipewire.

Ubuntu 26.04 note: If AetherSDR fails to start with a missing libOpenGL.so.0 error, install libopengl0. 26.04 stopped pulling it in by default for the desktop image; the build-deps line above includes it explicitly so this only bites users who install just the AppImage.

Build & Run

git clone https://github.com/aethersdr/AetherSDR.git
cd AetherSDR
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo
cmake --build build -j$(nproc)
./build/AetherSDR

RADE-enabled builds use a vendored Opus snapshot, so no additional Opus download is required during configure or build.

Windows 11

Prerequisites: Visual Studio 2022 (Build Tools, Community, or higher) with the MSVC C++ workload, CMake 3.25+, Ninja, and Qt 6.7+ (msvc2022_64; the release binaries ship 6.8.3 LTS).

:: 1. Activate the MSVC environment. Adjust the edition (BuildTools / Community /
::    Professional / Enterprise) to match your install; run "vswhere" if unsure.
"C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\Build\vcvars64.bat"

:: 2. Generate the single-precision FFTW import lib (needed by NR4/libspecbleach)
powershell -File scripts\setup\setup-fftw.ps1

:: 3. Configure. Ninja is required: the default Visual Studio generator is
::    multi-config (it ignores CMAKE_BUILD_TYPE) and takes a different
::    manifest-embed path. Point CMAKE_PREFIX_PATH at your Qt kit so
::    find_package(Qt6) resolves.
cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_PREFIX_PATH="C:/Qt/6.8.3/msvc2022_64"

:: 4. Build
cmake --build build --target AetherSDR

Qt 6.7+ for GPU Spectrum Rendering

GPU-accelerated spectrum/waterfall rendering requires Qt 6.7 or greater. If your distribution ships with an older version (e.g., Ubuntu 24.04, Debian 12, or Mint 21–22 include Qt 6.4.2), the build system automatically disables GPU rendering and falls back to the CPU-based QPainter path. (Release binaries ship Qt 6.8.3 LTS; the 6.7 floor is the source-build minimum for QRhi.)

To use GPU acceleration on these systems, install Qt 6.7+ manually:

1. Option 1: Using a PPA (Ubuntu/Mint) The kubuntu-backports PPA may provide a newer Qt — verify the version it ships before relying on it.

2. Option 2: Using the Qt Online Installer Install Qt into your home directory (e.g., ~/Qt/6.8.3/gcc_64). Because CMake otherwise defaults to the system-provided Qt, point it at the newer install with -DCMAKE_PREFIX_PATH:

bash cmake -B build -G Ninja \ -DCMAKE_PREFIX_PATH="$HOME/Qt/6.8.3/gcc_64" \ -DCMAKE_BUILD_TYPE=RelWithDebInfo

Make sure the qtshadertools and qt5compat (or equivalent) modules are selected in the Qt Online Installer along with qtbase.

Note: GPU rendering also needs the private QtGui headers (qt6-base-private-dev on Debian-family, included by default in the Qt Online Installer).

Install (optional, Linux)

sudo cmake --install build

Roadmap

• [ ] CW ultimatic keyer mode (#416)
• [ ] Native DAX audio channels on Windows

See the full issue tracker for all planned features.

Contributing

PRs, bug reports, and feature requests welcome! See CONTRIBUTING.md for guidelines.

Development environment: AetherSDR is developed using Claude Code as the primary development tool. We encourage contributors to use Claude Code for consistency. PRs must follow project conventions, pass CI, and include GPG-signed commits.

Not a developer? Click the lightbulb button in AetherSDR's title bar to create an AI-assisted bug report or feature request.

Verifying Downloads

Linux and Windows binaries are GPG-signed. macOS artifacts are Apple notarized. Each release includes .asc signatures and SHA256SUMS.txt.

curl -sSL https://raw.githubusercontent.com/aethersdr/AetherSDR/main/docs/RELEASE-SIGNING-KEY.pub.asc | gpg --import
gpg --verify AetherSDR-vX.Y.Z-x86_64.AppImage.asc AetherSDR-vX.Y.Z-x86_64.AppImage

See docs/VERIFYING-RELEASES.md for full instructions.

License

AetherSDR is free and open-source software licensed under the GNU General Public License v3.

AetherSDR is an independent project and is not affiliated with or endorsed by FlexRadio Systems.