Interesting bands to explore
A treasure map for your SDR. (Frequencies vary by country — here, Europe.)
| Band | What | On screen |
|---|---|---|
| 88–108 MHz | Commercial FM radio | wide (~200 kHz), stable stripes |
| 118–137 MHz | Aviation (AM) | intermittent carriers, voice |
| 1090 MHz | ADS-B: aircraft positions | very short, numerous bursts |
| 162 MHz | AIS: ship positions | bursts |
| 137 MHz | NOAA APT: weather-satellite imagery | slow sweep during a pass |
| 433 / 868 MHz | ISM: sensors, remotes, LoRa | brief, intermittent bursts |
| 2.4 GHz | WiFi, Bluetooth, drones | wide bands, frequency hopping |
For every target the approach is the same: the right antenna, tune, Le waterfall (cascade temporelle), identify the modulation. Some signals only need to be detected (presence), others can be decoded with a dedicated tool — see Détecter vs décoder.
The academy's missions train you on three of these bands:
Going further: the hunting notebook
| Band | What | Why it's fascinating |
|---|---|---|
| 27 MHz | Citizen Band | truckers — the licence-free ancestor of it all |
| 77.5 kHz | DCF77 (German atomic clock) | the official time of millions of alarm clocks |
| 131–137 MHz | ACARS | airliners' "text messages", decodable |
| 174–240 MHz | DAB+ | digital radio, big OFDM blocks |
| 400–406 MHz | Weather radiosondes | balloons at 30 km altitude — some people recover them on the ground! |
| 446 MHz | PMR446 | licence-free walkie-talkies |
| 466 MHz | POCSAG | hospital pagers, still alive |
Best hours: ISM wakes up in daytime (sensors, remotes), HF opens in the evening (propagation — see Propagation des ondes), and ADS-B never sleeps.
Responsible listening: observe and learn — never disclose the content of private communications, even decodable ones. Re-read Légal & sécurité before exploring.