AetherSDR

A cross-platform, open-source client for FlexRadio Systems transceivers

AetherSDR brings full FlexRadio operation to Linux, macOS, and Windows — each a native build, no Wine or virtual machines. A native aarch64 build also runs on Raspberry Pi and other embedded ARM devices. 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: 26.10.4 — CalVer (YY.M.patch[.hotfix]). | Download | Discussions | What's New

Native builds for Linux, macOS, and Windows — Linux AppImage (x86-64 + aarch64), macOS DMG (Apple Silicon + Intel), Windows installer and portable ZIP. Every platform is built, tested in CI, and released together.

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Highlights

• GPU-accelerated spectrum & waterfall — QRhi rendering (OpenGL/Metal/D3D11) with a per-pixel FFT trace at up to 60 fps, optional FFT Smooth and De-comb trace shaping, an optional 3D stacked-trace mode, ~71% less CPU than the paint path, GPU-composited slice flags and multi-GPU adapter selection
• Multi-slice & multi-panadapter — colour-coded VFO overlays, independent TX assignment, diversity/ESC beamforming, and up to 8 detachable pans with native VITA-49 waterfall tiles and per-flag S-meter / SmartMTR views
• KiwiSDR and Web-888 public-receiver browser — find and connect to public receivers worldwide through an API-policy-aware directory, with diversity receive and receive-only TX inhibit
• AetherTX and AetherRX — the transmit and receive chains, one window each. AetherTX is the channel strip (gate, EQ, compressor, de-esser, tube, AetherVoice exciter, reverb, brickwall limiter) with a preset library and scope; AetherRX puts noise reduction, gate, EQ, compressor, tube, AetherVoice and the output meter on tabs down its left edge
• Seven client-side noise-reduction engines, each denoising left and right independently so pans and diversity survive them — NR2 (spectral), RN2 (RNNoise), NR4 (libspecbleach), NNR (WDSP's Neural Noise Reduction), DFNR (DeepFilterNet3), BNR (the NVIDIA Maxine denoiser, in-process on a local RTX/GeForce GPU, Linux + Windows — docs/nvidia-bnr.md) and MNR (macOS)
• DAX virtual audio + IQ — up to 8 RX audio channels (radio-dependent) plus 1 TX, and 4 channels of raw I/Q at 24–192 kHz for WSJT-X / fldigi / VARA / JS8Call, with a per-slice WFM demodulator for satellite data
• AetherModem packet radio — KISS-over-TCP TNC, connected-mode AX.25 BBS, a personal mailbox, a WIDE1-1 fill-in digipeater, and an APRS client (station table, GPS beacon, messaging) on 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, FreeDV Reporter, N1MM+/DXLog contest bandmap, the EiBi shortwave schedule and the KiwiSDR DX Community database, with auto-mode switch and per-feed colouring
• Local voice keyer — twelve PC-microphone recordings up to 30 seconds each, with preview, import/export and F1–F12 playback; radio DVK remains available separately
• CW operator suite — ggmorse plus download-on-demand DeepCW and DeepFist receive decoders where ONNX Runtime is available (ggmorse only on Intel macOS), MIDI/keyboard straight-key and iambic paddles with full QSK, optional Quindar tones

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How AetherSDR Is Built

AetherSDR is developed through an AI-augmented open-source workflow. The project lead (Jeremy KK7GWY) and a core contributor team work primarily through Claude Code; contributors use a mix of AI tools (Codex, Copilot, Cursor, Gemini, Aider); and the AetherClaude orchestrator bot triages incoming issues, drafts implementation plans and opens PRs for anything labelled aetherclaude-eligible.

Every change passes the same gate regardless of which tool — or human — produced it: branch protection enforces signed commits, green CI and CODEOWNERS review, and nothing reaches main without human review. The project's Constitution (structured per Cisco's Foundry Constitution spec) codifies the conventions every contributor and every AI tool follows, and AGENTS.md is the canonical guide each assistant reads first.

At active pace that is roughly 50 PRs a week across six or more distinct AI tools. The full contributor list is auto-generated from commit attribution — see the Contributors graph.

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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, and — outside the radio seam entirely — ACOM S-series and SPE Expert (original 1K-FA / 1.3K-FA / 1.5K-FA / 2K-FA) amplifiers over serial or ser2net TCP, and VK3AMP (600 W / 1000 W / 2000 W) amplifiers over TCP control with UDP telemetry, and the Elecraft KPA1500 over TCP (not yet validated on hardware), the RF-KIT over its HTTP REST API (tested on an RF2K-S; other RF-KIT models untested), plus KPA500, KAT500 and KXPA100/KXAT100 over local serial or raw TCP, with Full/Mini applets and Advanced maintenance. Direct TGXL, PGXL and Antenna Genius connections authenticate with the device's access code.

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.

Other radio families ride the vendor-neutral IRadioBackend seam. None is a supported family yet (one Icom model is supported on its own, below), and FlexRadio remains the supported target:

• Hermes-Lite 2 — experimental. Four independent receivers, SSB, AM, DSB and simplex FM/NFM voice through WDSP's TXA modulator with a reduction-only ALC, CW/RTTY decoding, AX.25 packet, band switching with hardware filters, manual notch filters, a host-side impulse noise blanker, host frequency calibration, a derived dBm reference, an on-demand wideband bandscope, minimum-phase receive filtering outside CW, a declared board variant (bare HL2, AK4951 companion or SquareSDR 2), receive squelch, the CW audio peaking filter, RIT and XIT per receiver, backend-side FFT averaging, the CL1 external 10 MHz reference and per-radio state restore (AGC mode and threshold, TUNE power per band, FFT averaging, FPS and dBm range, receivers B–D with their own setpoints, and manual notches), and the N2ADR IO board's status registers.
• Networked Icom — early. CI-V over the RS-BA1 UDP transport, brought up on the IC-705 (receive, scope, transmit, FT8) and completed against a live IC-7300MK2 (controls, meters, ATU, WSPR, PC Audio routing and the CW decoder). The connect path asks the radio for its own CI-V address rather than assuming one. On the IC-7300MK2 and IC-705, and on the IC-9700, which is not yet verified, the panadapter runs in SCROLL-F, tuning in place and scrolling at its margins as on a Flex, with Center and Fixed selectable. Only the IC-705 and IC-7300MK2 are verified against their own CI-V guides — an unrecognised model gets no scope and no transmit rather than optimistic defaults. The IC-7300MK2 over built-in Ethernet/RS-BA1 is supported as of v26.9.5 (RFC #5517); every other Icom model keeps the early, experimental treatment.
• ANAN-G2 — experimental, receive-only. openHPSDR Protocol 2 discovery with a single receive path, spectrum and audio, live tuning and zoom, live DDC rate changes, and DDC0 edge-droop compensation derived from the Saturn gateware (an in-app calibration can override it). The panadapter is computed by WDSP's display analyzer at one point per screen pixel, and the S-meter, noise blanker and RF-gain attenuator work. The receiver's AF gain, mute and balance apply, and receive audio also plays through the radio's own speaker. AGC-T spans −20 to 120 dB, NB2 interpolates over impulses, the status bar shows the supply voltage and link, and frequency, mode, step, output level and dBm range are remembered per radio. Front-end settings are under Radio Setup → Radio, including receive band-pass filters that follow the tuned frequency and a speaker-amplifier mute; discovery probes each distinct attached IPv4 subnet. Transmit is a future phase.
• RTL-SDR — experimental, receive-only, bundled in every official package. Discovers supported USB dongles through and provides one panadapter and, at a normal launch, one host-demodulated slice, publishing only the receive state the dongle confirmed, with capture browsing, a 65,536-point zoom FFT, SSB/CW and AM/SAM reception, selected-receiver CW decoding and Copy Assist, WFM stereo, live PPM adjustment, per-receiver squelch and relative meters, and receive DAX/TCI feeds. Two, four or eight receivers are an explicit evaluation, not yet a production claim.

No radio at all? Demo mode runs the full UI against a synthetic backend that generates its own audio and spectrum.

Tested Controller Devices

AetherSDR supports external station-control hardware through USB serial, USB HID, MIDI, 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, manual mapping entry, importable/exportable profiles (including vendor-supplied SmartSDR .map files), and relative-encoder support
• AetherPad — an Arduino Giga R1 running the aether-pad RC-28 emulator firmware; over USB HID (hidapi builds) it drives the same RC-28 controls and LEDs
• Ulanzi Dial Bluetooth HID dial on Linux, Windows (hidapi builds) and macOS, its rotary and buttons mapped in Settings → Ulanzi Dial Mapping...
• Elgato Stream Deck+ natively over USB HID (hidapi builds), driving the LCD keys and the four encoder dials
• ELAD/WoodBoxRadio TMate 2 over USB HID (hidapi builds): three encoders, nine keys, and the LCD and backlight
• Other Stream Deck models, on any platform, through the TCI server or the automation bridge using the control-surface software of your choice — AetherSDR provides the protocol, not the button layer
• USB-serial PTT/CW interfaces for foot switches, straight keys, iambic paddles, amplifier keying lines, and external sequencers

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Download

Pre-built binaries are available from Releases:

Platform	Download	Notes
Linux x86_64	AetherSDR-*-x86_64.AppImage	Single file, no install needed. chmod +x and run.
Linux ARM	AetherSDR-*-aarch64.AppImage	Raspberry Pi, ARM laptops. chmod +x and run.
macOS Apple Silicon	AetherSDR-*-macOS-apple-silicon.dmg	Apple Silicon (M1+), macOS 14.4 or newer. Signed & notarized.
macOS Intel	AetherSDR-*-macOS-intel.dmg	Intel Macs, macOS 14.4 (Sonoma) or newer. Signed & notarized.
Windows Installer	AetherSDR-*-Windows-x64-setup.exe	Setup wizard with Start Menu shortcut and uninstaller.
Windows Portable	AetherSDR-*-Windows-x64-portable.zip	No install needed. Extract and run.

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Building from Source

Qt 6.12 is required — the Qt every release is built against. Few distros package it yet, so Qt comes from scripts/setup/setup-qt.sh (setup-qt.ps1 on Windows), which installs exactly the release Qt and qtkeychain in one command; CMake then finds it on its own. A distro Qt that is already 6.12 or newer also works. See docs/BUILDING.md for what the script checks and where it installs.

See BUILD-OPTIONS.md for compile-time switches, defaults and prerequisites, including optional decoders and experimental radio backends.

Dependencies

Everything except Qt and qtkeychain comes from the system. Optional packages are noted in the build docs; the build succeeds without them with the corresponding features disabled.

# Arch / CachyOS / Manjaro
sudo pacman -S cmake ninja pkgconf autoconf automake libtool python curl git \
  fftw rtl-sdr portaudio hidapi \
  libpulse libglvnd fontconfig libsecret wayland libxkbcommon-x11 pipewire \
  xcb-util-cursor xcb-util-image xcb-util-keysyms xcb-util-renderutil xcb-util-wm

# Debian / Ubuntu / Linux Mint
sudo apt install cmake ninja-build pkg-config autoconf automake libtool \
  python3 python3-venv curl git \
  libfftw3-dev librtlsdr-dev portaudio19-dev libhidapi-dev \
  libgl1-mesa-dev libpulse-dev libasound2-dev libpipewire-0.3-dev pipewire-bin \
  libdbus-1-dev libglib2.0-dev libsecret-1-dev libfontconfig1-dev libfreetype6-dev \
  libx11-dev libx11-xcb-dev libxcb1-dev libxkbcommon-dev libxkbcommon-x11-dev \
  libxcb-cursor0 libxcb-glx0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 \
  libxcb-randr0 libxcb-render-util0 libxcb-shape0 libxcb-sync1 libxcb-util1 \
  libxcb-xfixes0 libxcb-xinerama0 libxcb-xkb1 \
  libopengl0 gstreamer1.0-pulseaudio gstreamer1.0-plugins-base

# Fedora
sudo dnf install cmake ninja-build autoconf automake libtool python3 curl git \
  fftw3-devel rtl-sdr-devel portaudio-devel hidapi-devel \
  libglvnd-devel pulseaudio-libs-devel fontconfig-devel freetype-devel \
  dbus-devel glib2-devel libsecret-devel libX11-devel libxcb-devel \
  libxkbcommon-devel libxkbcommon-x11-devel \
  xcb-util-cursor xcb-util-image xcb-util-keysyms xcb-util-renderutil xcb-util-wm

# macOS (Homebrew); Qt needs Xcode 16 — see docs/BUILDING.md
brew install ninja cmake pkgconf autoconf automake libtool \
  fftw librtlsdr portaudio hidapi

Build & Run

git clone https://github.com/aethersdr/AetherSDR.git
cd AetherSDR
scripts/setup/setup-qt.sh            # Qt 6.12 (cached per user) + qtkeychain
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.

Install (optional, Linux)

sudo cmake --install build

Source installs depend on the Qt location used at build time. If that Qt generation is replaced, rebuild and reinstall AetherSDR before pruning the old Qt generation.

Platform setup and troubleshooting — Windows 11 and macOS step-by-step, the dependency-to-feature table, GPU/QRhi rendering and its AETHER_NO_GPU escape hatch, Wayland vs XWayland selection, and older-distro Qt: see docs/BUILDING.md.

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Roadmap

Currently in flight:

• aetherd — splitting a headless engine from thin UI clients across the vendor-neutral IRadioBackend seam that six backends already ride. Local receive control, bounded telemetry and credential-bound transmit grants with Flex PTT handoff have landed, and the desktop's slice receive controls travel as typed backend requests. Radio Setup, TX Band, USB, profile and memory controls, slice lifecycle and split routing, and panadapter/waterfall control now use that seam too; per-client propagation, transmit for the other families and a thin client to replace direct model access have not.
• Non-Flex backends — Hermes-Lite 2 (experimental), networked Icom (early; the IC-7300MK2 over RS-BA1 is supported), and ANAN-G2 and RTL-SDR (experimental, receive-only). Current coverage and remaining work for each is under Supported Hardware.
• Workspace canvas — an experimental alternative shell; remaining work is live cross-window drag and field time against the Classic shell.
• In-app updates (RFC #5304) — the check, badge and Updates window ship; the Windows install and restart wiring, then the other platforms, remain.
• The visual canon — the AetherSDR style guide (RFC #6226) is applied one surface at a time; the multiFLEX Dashboard, TX Band Settings, RC-28 mapping and FFTW Wisdom windows now join the earlier ones, and a single base-token flip comes last.
• AppSettings nested-JSON refactor — storage is on SQLite with per-radio versioned feature documents; the legacy flat keys still need migrating.
• Flathub submission — the AppStream metainfo and manpage are in; the Flathub PR and manifest are the remaining step.

See ROADMAP.md for the full picture and the community backlog, and the issue tracker for everything else.

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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? Choose Help → Submit your Idea... 💡 in AetherSDR to create an AI-assisted bug report or feature request.

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Related projects

• Aether-gate — put any radio into AetherSDR. A bridge that presents an Icom/Kenwood/Yaesu/Elecraft CAT rig (via Hamlib), an Icom LAN rig, or a SoapySDR dongle to AetherSDR as if it were a FlexRadio — live panadapter, waterfall, and frequency/mode control. Receive + control today (no transmit yet). By Nigel Fenton (G0JKN); GPL-3.0-or-later. (aethersdr/Aether-gate tracks upstream nigelfenton/Aether-gate.)

AetherSDR integrates radios that earn deep native support directly in-engine; the gate covers the long tail of legacy/CAT radios and dongles. Networked Icoms now have an in-engine CI-V backend, so for those the gate is the fallback for models the native backend does not yet cover.

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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.

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License

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

Bundled third-party libraries retain their own licenses (see each third_party/<lib>/LICENSE), all GPLv3-compatible. Notably, on-device speech-to-text uses whisper.cpp and ggml (MIT) — vendored under third_party/whisper.cpp/ (Vulkan/Metal GPU backends included); Whisper model weights are downloaded on demand and are MIT-licensed, not redistributed in this repository.

AetherSDR is an independent project and is not affiliated with or endorsed by FlexRadio Systems. D-STAR is a registered trademark of Icom Inc. AetherSDR is not affiliated with or endorsed by Icom Inc.