AntennaSim

Free, open-source antenna simulator for the browser -- powered by NEC2

_{...or self-host in one line: docker run -p 80:80 ea1fuo/antennasim}

17 antenna templates  ·  3D radiation patterns  ·  SWR & Smith charts  ·  Wire editor + optimizer  ·  NanoVNA overlay  ·  Dark / light theme

Antenna modeling without the install. No license fee, no Windows-only desktop app, no account -- open a browser (or your phone) and start designing. Powered by the same NEC2 engine the classic tools (EZNEC, 4nec2, MMANA-GAL) are built on.

Design antennas from built-in templates or build your own from scratch in the wire editor. Run NEC2 simulations and instantly visualize SWR, impedance, Smith chart, 3D radiation patterns, current distribution, and near-field heatmaps -- all in your browser.

Two deployment modes: self-hosted with Docker (backend + Redis) or fully static via WebAssembly on GitHub Pages -- zero server required.

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Quick Start

Prerequisites

• Docker and Docker Compose (v2+)
• That's it. No Python, Node.js, or nec2c installation needed.

One-liner (Docker Hub)

docker run -p 80:80 ea1fuo/antennasim

Open http://localhost in your browser. Done. This pulls the all-in-one image from Docker Hub with everything bundled (frontend, backend, Redis, nginx).

From source

git clone https://github.com/EA1FUO/AntennaSim.git
cd AntennaSim
cp .env.example .env
docker compose up --build

The first build takes a few minutes (downloading base images, compiling nec2c, installing dependencies). Subsequent starts are fast.

Prefer to run it without a server? AntennaSim also runs fully in the browser via WebAssembly -- see the Deployment guide.

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Documentation

Full guides live in the docs/ folder:

Guide	What's inside
Usage	Antenna templates, full feature list, keyboard shortcuts
Development	Dev setup, local WASM build, architecture, project structure, tech stack
Deployment	GitHub Pages (WebAssembly) and production Docker deployment
API Reference	REST + WebSocket endpoints and configuration (.env)

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Highlights

• 17 antenna templates -- dipoles, verticals, loops, Yagi/Moxon/Hex beams, LPDA, magnetic loop, and more (full list)
• Full NEC2 pipeline -- card deck generation, nec2c execution, and parsed results, all automated
• Interactive 3D viewport -- radiation patterns, current distribution with animated flow, near-field heatmaps
• Charts & analysis -- SWR, impedance, Smith chart, polar pattern, balun/unun matching, NanoVNA .s1p overlay
• Wire editor -- build arbitrary geometries, import/export .nec and .maa files
• Optimizer -- Nelder-Mead with 5 objective functions and real-time progress
• Runs anywhere -- desktop, tablet, or phone; touch-friendly controls and a responsive layout, no install or account

See the Usage guide for the complete feature list.

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Contributing

Contributions are welcome -- this is a free and open-source project for the amateur radio community. See CONTRIBUTING.md for setup, branch/commit conventions, and how to add an antenna template.

Found a bug or have an idea? Open an issue or a discussion.

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License

AntennaSim is free software released under the GNU General Public License v3.0.

You are free to use, modify, and distribute this software. If you distribute modified versions, they must also be released under the GPL-3.0. See LICENSE for the full text.

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Acknowledgments

• NEC2 -- the Numerical Electromagnetics Code developed at Lawrence Livermore National Laboratory. The foundation of antenna simulation for decades.
• nec2c -- the C translation of NEC2 by Neoklis Kyriazis (5B4AZ), making NEC2 accessible on modern systems.
• The amateur radio community -- for decades of antenna design knowledge, experimentation, and sharing.

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_{Built for amateur radio operators, by amateur radio operators.
73 de AntennaSim}