1.6 KiB
Context
The system monitors CB radio channels using RTLSDR-Airband running in Docker on a Pi 400. The SDR is tuned to a center frequency of 27.035 MHz with a 2.4 MHz sample rate, covering approximately 25.835–28.235 MHz. Three channels are currently monitored (3, 7, 10). CB channel 16 at 27.155 MHz falls well within this window.
Goals / Non-Goals
Goals:
- Add CB channel 16 (27.155 MHz) to the monitored channel list
- Use identical recording and squelch settings as existing channels for consistency
Non-Goals:
- Changing center frequency, sample rate, or gain settings
- Adding any other channels beyond channel 16
- Modifying the cleanup, web, or Docker configuration
Decisions
Use identical channel parameters as existing channels. All current channels use 8 kHz bandwidth, NFM modulation, 9.0 dB squelch SNR threshold, and file output with split-on-transmission. Channel 16 will use the same settings. There's no reason to deviate — CB channels have uniform characteristics.
Filename template follows existing convention: CB_CH16_27155.
This matches the CB_CH{nn}_{freq} pattern used by channels 3, 7, and 10, keeping recordings consistent for the cleanup script and web browser.
Risks / Trade-offs
Additional CPU load from fourth channel → Minimal risk. RTLSDR-Airband's multichannel mode handles many channels efficiently within a single FFT pass. One more channel adds negligible overhead on the Pi 400.
More recordings consuming disk space → Mitigated by the existing cleanup container which removes files under the 3k size threshold.