The model

Everything in antennaknobs is built on one small idea: an antenna is a function from parameters (the knobs) to a list of wires.

AntennaBuilder

A design subclasses AntennaBuilder and declares its parameters:

from antennaknobs import AntennaBuilder

class Builder(AntennaBuilder):
    default_params = {
        "design_freq": 28.47,
        "freq": 28.47,
        "length": 5.2,
        # ...
    }

    def build_wires(self):
        ...

Parameters are read and written as plain attributes (ant.length = 5.2); under the hood that’s backed by the parameter dict. Variant parameter sets (e.g. a design retuned for a different height or band) live alongside default_params, and a ui_params block carries hints for the web knobs (ranges, the default 3D view, and so on).

The build_wires() contract

build_wires() returns a flat list of edges, each a tuple:

((x0, y0, z0), (x1, y1, z1), nsegs, excitation)

• the two endpoints are 3D coordinates (metres),
• nsegs is how many segments to mesh that wire into,
• excitation is None for a structural wire, or a complex value for the driven segment carrying the source.

That single list is the entire interface to the solver and every renderer — nothing downstream cares how you produced it, which is what makes the geometry layer so flexible.

House conventions

• Angles are in degrees throughout, with a _deg suffix on parameter names (the web UI shows a compact °-suffixed label and the full program name in a tooltip).
• Segment counts are derived from a wire’s length relative to a reference (usually a quarter-wavelength) so meshing stays consistent across designs.

Ready to write one? Write your first design builds a tunable dipole from a single hardcoded wire, one change at a time.