Radio in motion – radio technology as animation
What happens in the cable and in the air is invisible. The animations make it visible: waves that propagate and superimpose, antennas that focus, modulation that shapes a spectrum. Every scene is adjustable and backed by calculation.
Open in the browser
No installation, no sign-up needed.
What the page does
- Wave propagation, superposition, standing waves
- Yagi directivity with gain and front-to-back ratio
- Smith chart with line transformation
- AM and FM spectrum with Bessel functions and Carson bandwidth
- Propagation via ground, ionosphere and troposphere
Background
With frequency modulation the power is distributed between carrier and sidebands whose amplitudes follow the Bessel functions of the modulation index. At an index of 2.405 the carrier vanishes completely – which lets you set the deviation of an FM transmitter precisely. Carson's rule estimates the bandwidth: B ≈ 2 · (Δf + f_m).
In practice
How it works: choose a scene and play with the sliders. With standing waves, change the load and watch nodes and antinodes move; with the Yagi, add directors and follow the gain. Each scene names the underlying formula and links to the matching exercises and calculators.
Frequently asked questions
Who are the animations for?
For anyone who wants to understand radio – from beginners to exam preparation.
Do they run on a smartphone?
Yes, all scenes adapt to the screen size.