method-of-moments antenna modeling

NECfull

A cross-platform antenna modeling app in the spirit of EZNEC. Build wire antennas, run a pure-Dart method-of-moments simulation, and inspect impedance, SWR, and radiation patterns — on desktop, mobile, or right here in your browser.

Launch the Web App View on GitHub

Runs entirely client-side — no install, no server.

What Is NECfull?

NECfull is a wire-antenna simulator written in Flutter/Dart. The simulation engine is a thin-wire Galerkin method of moments solving the mixed-potential electric field integral equation — the same class of numerical method used by NEC-5 and EZNEC. Lay out wires by their end coordinates, add voltage sources and lumped loads, pick a ground model, and NECfull computes the feedpoint impedance, current distribution, and full 3D radiation pattern. Everything runs locally in the browser; there is no server and nothing to install. Unlike EZNEC, it is open source and runs on Linux, MacOS and Windows.

Features

🧵

Wire geometry editor

Define straight wires by end coordinates, diameter, and segmentation. Coincident ends connect electrically, with a global Z-offset to raise or lower the whole antenna.

⚡

Sources & loads

Place voltage sources (magnitude/phase) and lumped loads (R+jX or series RLC) anywhere along a wire.

🌍

Ground models

Free space, perfect ground via image theory, and real ground using a Sommerfeld-Norton reflection-coefficient approximation.

📊

Impedance & SWR

Read feedpoint impedance, SWR, input power, and the full current distribution along every wire.

🧭

Radiation patterns

2D polar azimuth/elevation cuts with gain cursor, beamwidth, and front-to-back readouts, plus a rotatable 3D far-field gain surface.

🔄

3D geometry view

Rotatable 3D geometry with current-magnitude coloring so you can see where the RF actually flows.

📈

Frequency sweeps

Sweep across a band and chart SWR and R/X to find resonance and usable bandwidth.

💾

Save & load

Store models as JSON .nful files with open/save buttons in the toolbar.

✅

Accuracy check

The 3D gain surface reports an average-gain accuracy check so you can trust the numbers.

Built-in Antenna Templates

Start from a parameterized design (toolbar → “New antenna from template”) and NECfull turns the classic design formulas into real wire geometry, then solves it with the MoM engine:

Dipole Yagi-Uda Full-wave loop Vertical / ground plane Magnetic loop Log-periodic dipole array Axial-mode helix Moxon rectangle Phased verticals Corner reflector

Also ships with ready-to-run examples: a 20 m dipole, a free-space dipole, a 40 m vertical, a 40 m inverted V, and a 2 m 3-element Yagi.

Get Started

Launch the web app — no download required.
Pick a built-in example or start a new antenna from a template.
Edit wire coordinates, add a voltage source, and choose a ground model.
Set the frequency and hit solve to get impedance, SWR, and current.
Inspect the 2D pattern cuts and rotatable 3D gain surface.
Run a frequency sweep to find resonance and bandwidth, then save your .nful model.

Get NECfull

Run it now in your browser, or download a native desktop build.

Web App Source on GitHub

Windows x64 .zip macOS .dmg Linux x64 .AppImage Linux x64 .deb Linux x64 .tar.gz Linux arm64 .AppImage Linux arm64 .deb Linux arm64 .tar.gz All releases

The web build runs the solver on the main thread, so very large sweeps take a little longer than the native desktop build (which uses background isolates). File save dialogs are unavailable on web — use a desktop build to write .nful files.