Title: Capturing Signals
Description: Record and decode SubGHz signals from remotes and transmitters
URL: /v2.1/subghz/capturing/
Version: v2.1
Section: SubGHz
Search index: /search-index.json

# Capturing Signals

> Record and decode SubGHz signals from remotes and transmitters

## On this page

- [Before you start](#before-you-start)
- [Capture modes](#capture-modes)
- [Capturing a signal](#capturing-a-signal)
- [On-device UI](#on-device-ui)
- [Command line](#command-line)
- [Protocol decoding](#protocol-decoding)
- [File storage](#file-storage)
- [Tips for successful captures](#tips-for-successful-captures)
- [Notes](#notes)
- [Troubleshooting](#troubleshooting)

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Capture signals from remote controls, garage door openers, and other SubGHz devices. GhostESP automatically decodes supported protocols and saves signals for later replay.
## Before you start
- Hardware: Board with CC1101 SubGHz support (see [Hardware Support](/v2.1/subghz/hardware/)).
- SD card: Inserted and mounted so GhostESP can save .sub files under /mnt/ghostesp/subghz/.
- Frequency: Know or determine the target frequency using [Scanning](/v2.1/subghz/scanning/) or [Frequency Analyzer](/v2.1/subghz/freq-analyzer/).
## Capture modes
GhostESP supports two capture modes:
- Normal capture - Attempts to decode the signal using supported protocols. Best for known remotes and standard devices.
- Raw capture - Records raw timing data without decoding. Use for unknown protocols or when normal capture fails.
## Capturing a signal
### On-device UI
- Open SubGHz → Capture to start scanning on the current frequency.
- Press the button on your target remote while the scanner is running.
- When a signal is detected, GhostESP will attempt to decode it.
- Review the decoded information (protocol, bits, frequency) in the preview.
- Confirm to save the signal to the SD card.
### Command line
# Start the scanner
subghz start
# Enable raw capture mode (optional)
subghz capture_on
# Disable raw capture (return to normal mode)
subghz capture_off
# Capture the current signal
subghz capture [name_hint]
# Save the captured signal
subghz save [name_hint]
## Protocol decoding
GhostESP automatically attempts to decode captured signals using 30+ protocols including:
- Princeton
- CAME
- Nice Flo
- PT2260/PT2262
- Chamberlain
- Linear
- KeeLoq
- Dooya
- Dickert MAHS
- Nord ICE
- And many more (see [Supported Protocols](/v2.1/subghz/protocols/))
If the protocol is recognized, GhostESP displays:
- Protocol name
- Bit count
- Decoded code in hexadecimal
- Frequency
If decoding fails or the protocol is unknown, the signal is saved as raw timing data.
## File storage
Captured signals are saved as .sub files in /mnt/ghostesp/subghz/ using the Flipper SubGhz Key File format. See [Files](/v2.1/subghz/files/) for details on the file structure.
File names are auto-generated based on:
- Decoded protocol and code (if successful)
- Timestamp (if raw capture)
- Optional name hint provided during capture
## Tips for successful captures
- Frequency matching: Ensure you’re scanning on the correct frequency band for your target device.
- Distance: Start with the remote within 1-2 meters of the device for best signal quality.
- Multiple presses: Some remotes use rolling codes; capture multiple presses to identify patterns.
- Interference: Avoid areas with strong RF interference (near other transmitters, power lines, etc.).
- Raw fallback: If normal capture consistently fails, try raw capture mode to record the signal timings.
## Notes
- Captured signals are stored in Flipper-compatible format, allowing interchange with Flipper Zero devices.
- Rolling code protocols (like some KeeLoq implementations) may not replay successfully due to counter synchronization.
- Some devices require multiple button presses to transmit the full command sequence.
## Troubleshooting
- No signal detected: Verify the frequency band, check antenna connection, and ensure the target device is transmitting.
- Decode fails: Try raw capture mode, or move closer to the target device to improve signal quality.
- Save fails: Check that the SD card is mounted and the /mnt/ghostesp/subghz/ directory exists.
- Replay doesn’t work: Some protocols use rolling codes or require specific timing; raw capture may be necessary.