Act I — From a wire to a matrix
Why the answer is an integral equation, how a basis turns it into
Z I = V, and what the delta-gap feed really is. You leave with a
dipole solver you wrote yourself.
Start here →
A voltage in a gap
You put 1 volt across a tiny gap in a wire. What current flows, and what does it radiate? A method-of-moments primer, keyed line-by-line to a real solver.
What this is
Section titled “What this is”Most method-of-moments explanations stop at the blackboard, and most MoM codebases never explain themselves. This site does both at once: every chapter first builds the idea in ~20 lines of Python you can run, then shows the production version in momwire — the pure-Python MoM engine behind the antennaknobs simulator — and explains exactly what the engineering added. Source links are pinned to a release tag, every figure is generated by a checked-in script, and every number in the prose comes from a real run.
Act II — Bases and accuracy
Sinusoids (NEC’s bet), B-splines and junctions, quadrature done honestly, and how you know any of it is right. Coming next.
Act III — The ground
Mirror images, cheap real dirt via reflection coefficients, and paying full price with Sommerfeld integrals. Planned.
Act IV — Scale
N² is the enemy: batched frequency sweeps, ACA / H-matrices, arrays that know their own symmetry, and a compiled mirror of the Python spec. Planned.
The rules of the house
Section titled “The rules of the house”- The idea in 20 lines, the real thing in momwire. Naive runnable code first, production code second, and an honest account of the gap between them.
- One antenna, all the way down. A half-wave dipole carries the first three acts; it graduates to a yagi and a bowtie array when the story needs scale.
- Nothing typed from memory. Figures regenerate from scripts in the repo; source permalinks are pinned to a tag and checked at build time.
Turn the knobs live Everything in this primer runs when you drag a knob in the browser simulator.
antennaknobs docs The workbench built on momwire — designs as Python code, solver guide, benchmarks.