Welcome to the library

This is the "book" side of OpenHertz: an interconnected knowledge base on SDR and the HackRF, written to take you from "what is a wave?" all the way to "I detected a drone". Notes link to each other (click the highlighted links) and are welded to the missions: every concept has a button to go see it live.

Where to start?

1. The basics: Les ondes radio → Les décibels (dB et dBm) → Bruit de fond, SNR et sensibilité
2. Going digital: Échantillonnage, Nyquist et aliasing → Les échantillons I/Q
3. Seeing the signal: De l'IQ au spectre : la FFT → Le waterfall (cascade temporelle)
4. The hardware: C'est quoi un SDR ? → Le HackRF One → Antennes
5. Understanding signals: Modulations : graver l'information sur une onde
6. In the field: Bien l'utiliser en live : la méthode → Bandes intéressantes à explorer → Détecter vs décoder → Légal & sécurité

Preparing for the amateur-radio exam? A dedicated track covers the whole syllabus (regulations, technical, propagation, operating): start with Préparer l'examen radioamateur.

How does it work? Plug in your SDR (or stay on the simulator), open a mission, and come back to read the theory whenever a word escapes you. Practice and reading reinforce each other.

👉 Ready? Start with First contact