OpenFreq

Real-time network voice radio with real-time physics simulation for Falcon BMS.

Features

• Seamless integration into Falcon BMS - no extra configuration required
• Realistic radio propagation: signal strength, line-of-sight, Doppler and more (via OpenFreqAudio)
• Frequency-based voice channels with per-channel PTT and hotkeys (keyboard or joystick)
• Squelch simulation
• Hot-swappable audio devices
• Dedicated GCI (Ground Controlled Intercept) client mode with unlimited positions & channels
• Full 3D audio effects enabled in GCI mode — identical physics simulation as BMS mode
• GCI Position sources: static via map UI picker & address search or live Tacview/ACMI feed
• Transmitter / Receiver performance presets and SFX
• Opus audio compression and modern RTP stack
• Peer list
• Experimental: sidetone (microphone monitoring)
• Server: Native Windows & Linux support
• Client: Native Windows & Linux support (GCI mode only), BMS mode tested in WINE (see the Handbook for detailed WINE info)

Quick Start

BMS Mode

1. Make sure IVC is not running
2. Launch BMS and OpenFreq in any order
3. Check that OpenFreq is set to BMS mode
4. Connect via BMS UI and enter OpenFreq server address in the BMS IVC field. Make sure the IVC checkbox is selected in BMS.

GCI Mode

Note: BMS is not required for GCI Mode

1. Launch OpenFreq Client, set it to GCI Mode
2. Select Theater. Linux: specify Theater heightmap file
3. Enter connection data and Display name, Connect
4. Don't forget to switch to "Game" mode when clients move to 3D

Server

1. Verify ports 9987 (TCP), 9988 (UDP) are open (default configuration)
2. Launch OpenFreq Server (sensible defaults preconfigured)
3. The configuration file is automatically created (OpenFreq.Server.json) - adapt and restart if necessary

Documentation

See the Handbook for in-depth usage and configuration.

Requirements

• Self-contained builds — no dependencies, runs as-is
• Framework-dependent builds — requires .NET 10.0 Runtime
• Building from source — requires .NET 10.0 SDK

Architecture

Component	Role
OpenFreq.Server	Central relay — signaling (WebSocket) + audio (UDP)
OpenFreq.Client	Avalonia desktop GUI for end users
OpenFreq.Common	Shared protocol, RTP pipeline, jitter buffer
OpenFreq.Testclient	Minimal CLI client for testing

Build & Run

# Build all
dotnet build OpenFreq.sln

# Run server
dotnet run --project OpenFreq.Server/OpenFreq.Server.csproj

# Run client
dotnet run --project OpenFreq.Client/OpenFreq.Client.csproj

Contributing

Pull requests are welcome. Due to the complexity of the project, please keep them small. For bugfixes, please specify clear testing/repro cases.

License

Mozilla Public License 2.0