Before bands, channels and modulation there is the physics underneath them. These topics cover the few ideas that every later topic leans on: what a wave is, how waves add up, and how engineers talk about power. Each one has live models you can move.
TopicsStart with waves
Frequency and wavelengthWavesFrequency, wavelength, period, amplitude and phase, and what happens when two waves meet.dB, dBm and dBiDecibelsWhy Wi-Fi power is written in decibels, and how to add gains and losses along a chain.Path loss and antennasPropagationHow far a signal reaches, what antennas do, and how to build a link budget.
Why this comes first. Almost every Wi-Fi puzzle is one of two things: a wave that arrived weaker than the receiver needs, or waves that arrived at the wrong moment and cancelled. These two topics give you the vocabulary for both.