Title: Capturing Signals
Description: Record and decode SubGHz signals from remotes and transmitters
URL: /latest/subghz/capturing/
Version: latest
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 (On-Device UI)](#capturing-a-signal-on-device-ui)
- [Capturing a Spectrum Snapshot (CLI)](#capturing-a-spectrum-snapshot-cli)
- [Protocol Decoding](#protocol-decoding)
- [Tips for Successful Captures](#tips-for-successful-captures)
- [Notes](#notes)
- [Troubleshooting](#troubleshooting)

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Capture SubGHz activity from remote controls, garage door openers, and other SubGHz devices. There are two separate capture paths:
- On-device UI - captures and decodes real signals and writes Flipper .sub files for later replay.
- subghz CLI - captures RSSI spectrum snapshots (the 64 levels the scanner shows), not decodable signals, and cannot transmit.
Both paths write under /mnt/ghostesp/subghz/ on the SD card, but produce different files; see [Files and Management](/latest/subghz/files/) for the formats.
## Before You Start
- Hardware: Board with CC1101 SubGHz support (see [Hardware Support](/latest/subghz/hardware/)).
- SD card: Inserted and mounted. CLI snapshots and on-device .sub files both live under /mnt/ghostesp/subghz/.
- Frequency: Know or determine the target frequency using [Scanning](/latest/subghz/scanning/) or [Frequency Analyzer](/latest/subghz/freq-analyzer/).
## Capture Modes
The on-device signal capture supports two 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.
subghz capture_on / subghz capture_off select raw mode for that on-device/remote signal-capture path. They have no effect on the CLI spectrum snapshot.
## Capturing a Signal (On-Device UI)
- Open Menu → 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.
## Capturing a Spectrum Snapshot (CLI)
The CLI works on the scanner’s RSSI level buffer, not on decoded signals. A snapshot records the current name, cursor and 64 levels values - it is a picture of RF activity, not a signal you can replay or transmit.
# Start the scanner
subghz start
# Capture the current RSSI spectrum into the snapshot buffer
subghz capture [name_hint]
# Save the captured spectrum snapshot to the SD card
subghz save [name_hint]
subghz load and subghz replay restore a saved snapshot back into the scanner display; neither transmits. Snapshot names are auto-generated as snapshot_%08X (based on the tick counter) unless you pass a name hint.
## Protocol Decoding
The on-device capture path 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](/latest/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.
## 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
- On-device captured signals are stored in Flipper-compatible format, allowing interchange with Flipper Zero devices.
- 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.