Skip to content

AntennaKNoBs

Turn a knob, watch the antenna. A browser-based wire-antenna MoM simulator — no install, no NEC deck to hand-write.

New in v0.86.0

One range for the dial and the sweep. The measurement dial now travels exactly the band the sweep covers: right-click it (long-press on touch) to set the range, a step or a point count, and linear or log spacing, and a deck’s own sweep arrives with the file. SimNEC files round-trip more faithfully: loads and insulated wires export in the forms SimNEC applies, JamSegments counts are honoured, and every block of a station is a measurement plane, with rig at the generator and feed at the antenna. The NEC-2 engine now solves the network decks NEC-5 does, razor-2p serves buried radials on momwire 0.62, and a rescan button picks up a design file you just dropped into your folder.

antennaknobs describes an antenna as Python code — a small parametric builder, its geometry computed from named knobs — then lets you explore it two ways: drive it from a script (sweep, optimize, compare, export a NEC deck), or open it in a browser and turn the knobs live, watching the radiation pattern, SWR, and impedance respond as you drag. Most antenna tools are a static formula calculator or a desktop app you have to install; this is neither.

A live modeling session, end to end: a 10 m Moxon built from knobs, tuned by dragging, and read out in real time.

And the other half of the story — writing an antenna as code: a full tutorial building a parameterized single-wire dipole from an empty file to knobs turning in the workbench.

Antennas as Python code

Describe an antenna once as a small parametric builder — geometry computed from named knobs — then sweep, optimize, compare, or open it in the browser. Most tools make you hand-place every coordinate.

Multi-basis MoM

Sinusoidal and B-spline bases in one engine, cross-validating each other — basis quality that otherwise costs four figures in commercial tools.

Fast on big arrays

H-matrix / ACA acceleration with GMRES, where every free NEC tool is dense O(N²). Demonstrated O(N log N) on a 2142-segment Yagi.

Cross-checked physics

A NEC-2 reference engine runs alongside the in-house solver — and a licensed NEC-5 can join as a third — so you get a built-in accuracy check most tools lack.

No platform lock-in

A web UI by default — works anywhere a browser does, while the competition is Windows/Linux/macOS desktop-only or a GUI-less library.