rtl_433

What is rtl_433?#

rtl_433 is an open-source tool that decodes radio signals in the 433 MHz ISM band (and other frequencies). It supports a wide range of devices: weather stations, tire pressure sensors, wireless thermometers, domotic remotes, and many other IoT sensors.

Despite the name, rtl_433 works with any SDR supported by SoapySDR, not just RTL-SDR dongles.

Installation#

sudo dnf install rtl_433

Usage#

Live Capture with BladeRF#

Listen on 433.92 MHz using a BladeRF via SoapySDR:

rtl_433 -d soapy=0,driver=bladerf -f 433920000 -g 60

Analysis Mode#

Use -A to enable analysis mode, which prints detailed pulse/gap timing information and attempts to guess the modulation:

rtl_433 -d soapy=0,driver=bladerf -f 433920000 -g 60 -A

Saving Signals#

Use -S 2M to save detected signals as .cs16 files (complex signed 16-bit IQ samples):

rtl_433 -d soapy=0,driver=bladerf -f 433920000 -g 60 -A -S 2M

Files are numbered sequentially (g001_433.92M_250k.cs16, g002_433.92M_250k.cs16, …), preserving chronological order.

Replaying Captured Signals#

Replay a single .cs16 file:

rtl_433 -r g001_433.92M_250k.cs16 -A

Batch Analysis#

Replay all captured files and count occurrences of each decoded frame:

for f in *.cs16; do rtl_433 -r "$f" -A 2>/dev/null; done \
  | grep "^codes" | sort | uniq -c | sort -rn

Extract unique codes of a specific size in capture order:

for f in $(ls -1 *.cs16 | sort); do rtl_433 -r "$f" -A 2>/dev/null | grep "^codes.*{52}"; done | awk '!seen[$0]++'

Key Flags#

File Format#

Saved signals use the .cs16 format: complex signed 16-bit IQ samples. The filename encodes the capture frequency and sample rate (e.g., g001_433.92M_250k.cs16 = 433.92 MHz at 250 kSPS).

Related Articles#

• Analyzing 433 MHz Signals with BladeRF

References#

• rtl_433 GitHub
• rtl_433 Wiki