Field Report: Mapping the 433 MHz Spectrum in Berlin

Between March 18-20, we conducted a passive RF spectrum mapping operation across central Berlin using 4 M0M0-Spectrum units in a distributed grid pattern.

Total signals detected: 2,847 unique transmissions across the 433.92 MHz ISM band. 68% identified as commercial garage remotes, 14% weather stations, 9% car key fobs, 4% alarm systems, and 5% unidentified protocols.

Hot zones with highest signal density correlated tightly with residential areas. Industrial zones showed surprising 868 MHz LoRa traffic — likely IoT inventory systems.

Unexpected: persistent 433.78 MHz beacon detected in Friedrichshain, transmitting every 47 seconds with consistent payload. Origin unknown. Investigation ongoing.

All findings disclosed to local CERT. No replay attacks performed — survey was strictly passive observation.