MeshHall-SAME

A NOAA SAME/EAS alert decoder for the MeshHall MeshCore bot.

Decodes NOAA Weather Radio SAME headers via RTL-SDR and writes alerts directly to a MeshHall SQLite database. The main bot then serves them via !alerts and !alert <id> with zero internet dependency.

Runs as a separate systemd service alongside MeshHall. Both share the same SQLite database safely via WAL mode.

Status: Untested - My hardware for validation isn't working. The decoder logic is complete but has not been run against a live RTL-SDR + NOAA signal. Contributions and test reports welcome.

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Disclaimer

There is no warranty of fitness of this code for any purpose. It was originally written to meet my needs of running on a Raspberry Pi 3B+, but likely will work on other Linux or Unix-like operating systems.

This code is developed with both human authoring and agentic assistance.

Requirements

Hardware

• RTL-SDR dongle (RTL2832U-based, e.g. RTL-SDR Blog v3)
• Antenna suitable for 162 MHz (VHF weather band)

Software

sudo apt install rtl-sdr multimon-ng

Python dependencies are minimal - the decoder uses only stdlib plus the aiosqlite package already present in a MeshHall venv.

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Installation

1. Clone or copy this repository to the Pi

git clone <repo> ~/meshhall-same
cd ~/meshhall-same

2. Run the installer (as root)

The installer creates a meshhall-same service account, installs to /opt/meshhall-same, creates a Python venv, installs dependencies, and registers the systemd service. It detects whether a previous version is installed and upgrades in place.

sudo bash install.sh

Options:

--yes               Skip all confirmation prompts (for automation)
--install-dir PATH  Custom install path (default: /opt/meshhall-same)
--db-path PATH      MeshHall database path (default: /opt/meshhall/data/meshhall.db)

3. Find your strongest NOAA WX frequency

NOAA Weather Radio broadcasts on one of seven frequencies (MHz):

162.400  162.425  162.450  162.475  162.500  162.525  162.550

Find the strongest station in your area: https://www.weather.gov/nwr/station_listing

4. Set your frequency in the service file

sudo nano /etc/systemd/system/meshhall-same.service
# Edit the --freq argument in the ExecStart line
sudo systemctl daemon-reload

5. Start the service

sudo systemctl start meshhall-same

# Watch logs
sudo journalctl -u meshhall-same -f

Upgrading

Run the installer again - it detects the existing installation and upgrades in place without touching any configuration:

sudo bash install.sh

Uninstalling

sudo bash uninstall.sh

The MeshHall database is not touched - alerts already decoded remain queryable via !alerts.

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Usage

# Run manually (stop the service first)
sudo systemctl stop meshhall-same
/opt/meshhall-same/venv/bin/python /opt/meshhall-same/same_decoder.py \
    --db /opt/meshhall/data/meshhall.db \
    --freq 162.550M \
    --device 0

Multiple RTL-SDR dongles are supported - duplicate the service file with --device 1 and a different --freq for a second dongle.

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How It Works

rtl_fm (tunes SDR to WX freq) → multimon-ng (decodes SAME headers) → same_decoder.py → SQLite

same_decoder.py parses the SAME protocol fields (event code, FIPS codes, duration, originator) and writes decoded alerts to the alerts table in MeshHall's database. The main bot reads from this table for !alerts and !alert <id> responses.

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Database Schema

The decoder writes to the alerts table, which is expected to already exist in the MeshHall database (created by the weather plugin's schema registration). Do not run the decoder against a database that hasn't been initialized by MeshHall at least once.

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License

GPLv3 - see LICENSE file for full license text.