## 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.