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Tune FFT size and squelch to reduce false-positive recordings

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Increase fft_size from 512 (default) to 2048 for better NFM channel
isolation, and add squelch_snr_threshold = 15.0 dB per channel to
reject noise-triggered recordings.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Michael Smith
2026-03-19 13:25:37 +00:00
parent 9ff0506cae
commit 733fe76ed5
7 changed files with 122 additions and 1 deletions
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17
openspec/specs/false-positive-reduction/spec.md Normal file
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### Requirement: FFT size configured for NFM channel isolation
The system SHALL use an `fft_size` of 2048 or greater to provide sufficient spectral resolution for separating NFM channels spaced 10 kHz apart.
#### Scenario: FFT size set in config
- **WHEN** the RTLSDR-Airband configuration is loaded
- **THEN** the `fft_size` is set to 2048
### Requirement: Squelch SNR threshold configured per channel
Each monitored channel SHALL have a `squelch_snr_threshold` set to reduce false triggers from noise and weak signals.
#### Scenario: Squelch threshold applied
- **WHEN** a signal is detected on a monitored channel
- **THEN** the squelch only opens if the signal exceeds the configured SNR threshold (starting value: 15.0 dB)
#### Scenario: Noise below threshold is rejected
- **WHEN** noise or interference is present but below the SNR threshold
- **THEN** no recording is triggered