02 — Antennas
Ranges, regions and practical geometry.
Which field region a test distance sits in, and how to pull real numbers out of a manufacturer's beamwidth plot — the practical side of antennas in test work. A rebuilt polarisation and aperture-coupling explainer is in the workshop, and the beam coverage animator grows as more antennas are digitised.
Tools
Antenna Region Plotter
Reactive, transition and Fraunhofer far-field regions against frequency, antenna size and test distance.
Open → 02Frequency Beamwidth Reader
Digitise E- and H-plane beamwidth curves from a datasheet plot in four guided steps, then export CSV.
Open → 03Beam Coverage Animator
Watch a horn's beam breathe across its band, and get the worst-case beamwidth and real coverage at your test distance.
Open →Hard-won
The antenna doesn't care what the datasheet says — it cares where you put it.
Where it comes from
From tracking radars to near-field ranges.
My first antennas were part of the radar systems at QinetiQ Aberporth, tracking aircraft entering a weapons test range and pulling telemetry from targets and payloads. At Powerlink the scale shrank to the bench: RF amplifiers, tuning, and test equipment you could hold.
Airbus brought my first planar range and pulled antenna measurement, EMC and spacecraft qualification together. At Mangata, as Director of Spacecraft Test, that turned into working with suppliers on how a spherical near-field range could be built into a satellite test facility in Scotland — antenna measurement not as a test, but as a building.