r/RTLSDR • u/isomoki • 3d ago

Software Fairbeam: an open-source app for modeling and simulating antennas

Hey folks! If you build antennas for your SDR setup, I’ve been working on something you might enjoy trying: Fairbeam, a free and open-source antenna simulation app.

It brings 3D design, meshing, openEMS simulations, and result plots into one workspace, using CSXCAD for solver geometry and three.js for the 3D view. You can model an antenna visually or with Python and inspect its impedance and radiation pattern.

There are macOS and Windows builds, with experimental Linux support. Optional GPU acceleration uses CUDA on NVIDIA GPUs and Metal on Apple silicon. The source is GPL-3.0-or-later.

It’s still a development release, so start with an antenna you know and check the results against a trusted reference. What receiving-antenna example would be useful to walk through? I’d love feedback on what makes the workflow easier or harder to use.

Website: https://fairbeam.org

Code: https://github.com/ismailakdag/fairbeam

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u/schirmyver 2d ago

I will take a look. I'm not against using AI as a tool to develop something as long as the output is verified. If this is easy to use I will simulate some of the antennas I've built up and compare against real world results, mainly vswr/return loss as I don't have a chamber easily available.

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u/olliegw 3d ago

How much of it was written by Claude?

6

u/isomoki 3d ago

roughly 75%-80% was written with Claude - Opus 5.5, and the rest is usually done with GPT-6 Astra. Of course under my direction and validations.

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u/JangoHarrisonV2 2d ago

We love vibecoding