A professional Emergency Alert System (EAS) research platform — CAP ingestion, SAME encoding, SDR verification, and multi-channel distribution, all on commodity hardware.

EAS Station is a software-defined drop-in replacement for commercial EAS encoder/decoder hardware costing $5,000–$7,000, built on a Raspberry Pi or any Linux server. It delivers a complete, automated CAP-to-broadcast workflow with PostGIS spatial intelligence, real-time SDR verification, and a polished web dashboard — wired together from boring, battle-tested open-source components.

⚠️ Laboratory Use Only — EAS Station is experimental software for research, training, and development. It is not FCC-certified and must only be used in controlled test environments. Never connect to production broadcast chains or on-air RF. See Legal & Compliance.

• NOAA/NWS CAP feeds — poll and parse all active weather alerts for your region
• FEMA IPAWS — federal Integrated Public Alert and Warning System integration
• Custom CAP endpoints — add any CAP 1.2-compatible feed source
• Automatic deduplication — stores once, no duplicate processing
• FIPS & NWS zone lookup — built-in setup wizard to find the right codes for your coverage area

• Full SAME encoding — generates bit-perfect Specific Area Message Encoding headers per FCC Part 11
• Attention tone synthesis — 853/960 Hz two-tone sequence generated in software
• Text-to-Speech voice-over — eSpeak TTS narrates alert details automatically
• Manual EAS print — compose and broadcast custom SAME messages for drills and tests
• Raw SAME parser — paste any ZCZC-… string for instant field-by-field decode and validation
• MDC1200 selective calling — optional 1200-baud FFSK pre/post signaling for forwarding EAS audio over Motorola-style two-way radio systems. Supports PTT-ID, Emergency, Request-to-Talk, Remote Monitor, Call Alert, and Voice Selective Call (unmute a specific target subscriber), plus DTMF tone bursts. See Alert Signals guide.

• County/state spatial filtering — alerts matched to your exact geographic footprint
• Polygon-based targeting — NWS zones, FIPS codes, and custom shapefile boundaries
• Interactive Leaflet maps — visualize alert areas and your coverage zone in the web UI
• Shapefile import — load ESRI boundary data directly into PostGIS for custom regions
• US Census TIGER/Line integration for authoritative boundary data

• RTL-SDR and Airspy support via SoapySDR abstraction layer
• FM demodulation — tunes to 162 MHz NOAA Weather Radio and custom frequencies
• Live SAME decode — decodes received EAS headers in real time to confirm broadcast
• Audio spectrum monitoring — waveform display and signal metrics in the dashboard
• Icecast streaming — demodulated audio streamed over HTTP for remote monitoring
• Multi-bitrate stream profiles — configure multiple Icecast streams with different formats

• GPIO relay control — switch transmitters, PTT lines, and external equipment
• LED sign support — RS-232 protocol driver for scrolling marquee displays
• OLED display — I2C status display showing current alert and system state
• VFD (Vacuum Fluorescent Display) — custom screen editor and graphic support
• Zigbee integration — optional wireless sensor/device control
• Multi-relay HAT support — coordinate multiple relay outputs for complex workflows
• GPIO pin map — visual interface showing every pin assignment and current state

• GPS-disciplined precision time — a Uputronics Raspberry Pi GPS/RTC HAT (u-blox MAX-M8Q multi-GNSS: GPS, GLONASS, Galileo, BeiDou) with hardware PPS delivers sub-microsecond reference time directly to the kernel
• True stratum 1 — chrony consumes the NMEA fix and the PPS edge as a kernel refclock, so the station serves NTP at stratum 1 with no upstream internet time required. Logged alert timestamps, audit trails, and SAME header JJJHHMM fields are accurate to the satellites themselves.
• Real broadcast-grade hardware — battery-backed RTC (RV-3028-C7 on current revisions, DS3231 on older boards) keeps the clock disciplined across power cycles even before GPS lock, and survives complete network isolation. Adafruit Ultimate GPS HAT (#2324, MTK3339) is supported as a drop-in alternative; any standard 9600-baud NMEA UART module with PPS will also work.
• One-click setup — Admin → Hardware Settings → GPS runs a checklist that probes every prerequisite (RTC overlay, PPS device, gpsd/chrony/util-linux-extra package state, /boot/firmware/config.txt overlays, chrony's currently-selected source) and offers a single Run button per remediation step. RTC seeding after a coin-cell change is one click.
• Live status in the dashboard — fix quality, satellite count, HDOP, sky plot, PPS pill, and chronyc tracking are surfaced in real time so an operator can prove stratum 1 lock at a glance.
• Why it matters — every EAS event is timestamped, geofenced, and audited; a station that drifts seconds against NIST is a station whose RWT logs and CAP sent/effective/expires math eventually cease to match the real world. Timing is treated as first-class infrastructure, not an afterthought.

See the GPS HAT Setup guide for hardware options, wiring, and the manual configuration steps the admin UI automates.

• Responsive Bootstrap 5 UI — works on desktop, tablet, and mobile
• Real-time updates — Socket.IO pushes live alert and system data without page refresh
• Alert timeline — full history with search, filter, and detail view
• Analytics dashboard — alert frequency, type breakdown, and geographic distribution charts (Chart.js), with one-click PDF export of the full statistics report (jsPDF + html2canvas)
• Audio monitoring — live receive history, source routing view, and playback
• System health panel — CPU, memory, disk, and service status at a glance
• Operator-selectable display units — coords (D.dddd / DMS), altitude (m / ft), speed (kn / mph / km/h / m/s) and distance (m / ft / mi / nmi) chosen per-browser via Settings → Personalization → Display Units (also reachable from the Help dropdown and the inline Units button on the GPS Dashboard and System Health pages)
• Dark-mode-friendly design with accessible color system

• Role-based access control (RBAC) — admin, operator, and viewer roles
• Multi-factor authentication (MFA) — TOTP-based second factor for all accounts
• API key management — generate and revoke keys for automation integrations
• Built-in HTTPS — nginx reverse proxy with Let's Encrypt auto-provisioning
• Self-signed fallback — works out of the box before DNS/cert setup

• Email alerts — configurable SMTP for alert and system health notifications
• SMS — outbound SMS notifications for critical alerts
• SNMP v2c traps — send traps to any NMS target for system health events

• Required Weekly Test (RWT) scheduler — automatically generates and schedules FCC-required weekly EAS tests
• Required Monthly Test (RMT) support — configurable monthly test scheduling
• Cron-style scheduling — flexible time rules for any recurring broadcast task

• Settings Hub — single /settings dashboard with links to every configuration page
• Stream Profile Manager — multi-stream Icecast configuration with bitrate and format control
• sudo eas-config — interactive whiptail TUI to reconfigure any .env setting without manual file editing
• Alembic database migrations — schema upgrades run automatically on update
• Comprehensive diagnostics — built-in web diagnostics page and CLI scripts for SDR, network, and database
• Alert Self-Test — replay bundled RWT captures to verify your FIPS codes trigger correctly
• System logs viewer — tail journalctl logs from any service directly in the browser
• Docs viewer — browse the full 90+ document library from within the web UI

• Full REST API namespaced under /api/
• X-API-Key header authentication — keys generated in the web UI
• Endpoints for alerts, GPIO, audio, streaming, and system control
• JavaScript API client for browser-side integrations
• Complete API reference →

Five focused systemd services with clear ownership — a web crash won't affect audio, and a hardware fault won't bring down the dashboard.

graph TB
    subgraph External["External Sources"]
        SRC[Alert Sources<br/>NOAA · IPAWS · CAP]
        RF[RF Signals<br/>162 MHz · SDR]
    end

    subgraph Services["Systemd Services"]
        POLL[eas-station-poller<br/>CAP Feed Polling]
        WEB[eas-station-web<br/>Flask · Gunicorn]
        SDR_SVC[eas-station-sdr<br/>SDR Hardware]
        AUDIO_SVC[eas-station-audio<br/>EAS Monitoring]
        HW_SVC[eas-station-hardware<br/>GPIO · Displays]
    end

    subgraph Infrastructure["Infrastructure"]
        DB[(PostgreSQL 17<br/>+ PostGIS 3.4)]
        REDIS[(Redis 7<br/>Cache · Pub/Sub)]
        NGINX[nginx<br/>HTTPS · Proxy]
    end

    subgraph Output["Outputs"]
        TX[FM Transmitter<br/>GPIO Relay]
        UI[Web Browser<br/>HTTPS]
        LED[LED · OLED · VFD<br/>Displays]
        STREAM[Icecast<br/>Audio Stream]
    end

    SRC -->|CAP XML| POLL
    RF --> SDR_SVC

    POLL -->|Store Alerts| DB
    WEB -->|Query Data| DB
    WEB -->|Commands| REDIS
    SDR_SVC -->|IQ Samples| REDIS
    AUDIO_SVC -->|Decode| REDIS

    NGINX -->|Reverse Proxy| WEB
    WEB --> UI
    HW_SVC -->|Relay Control| TX
    HW_SVC -->|Messages| LED
    SDR_SVC -->|Demod Audio| STREAM

    style External fill:#3b82f6,color:#fff
    style DB fill:#8b5cf6,color:#fff
    style WEB fill:#10b981,color:#fff
    style AUDIO_SVC fill:#f59e0b,color:#000
    style UI fill:#6366f1,color:#fff

Infrastructure: PostgreSQL 17 + PostGIS 3.4 for persistent storage · Redis 7 for real-time metrics and inter-service messaging · nginx for HTTPS termination.

Frontend libraries (all vendored locally under static/vendor/): Bootstrap 5, jQuery, Font Awesome, Leaflet (maps), Mermaid (diagrams), Chart.js 3 with the datalabels, matrix and date-fns adapter plugins (dashboards), and jsPDF + html2canvas (client-side PDF report export from the Statistics dashboard).

git clone https://github.com/KR8MER/eas-station.git
cd eas-station
sudo bash install.sh

The interactive whiptail TUI installer guides you through every option and then handles everything automatically:

Then open https://your-server-ip and log in — your station is live.

💡 Debian 13 (Trixie) and Python 3.13 are fully supported. The installer auto-detects your OS and selects the right packages.

cd /opt/eas-station
sudo bash update.sh

Backs up optionally → stops services → pulls latest code → preserves .env → migrates database → restarts everything.

sudo eas-config        # interactive whiptail TUI for any .env setting

Or visit /settings in the web UI to configure hardware, Icecast, notifications, TTS, FIPS codes, and more.

sudo bash uninstall.sh   # stops services, removes files, optionally removes PostgreSQL/Redis/nginx

The install script handles all system packages and Python dependencies automatically. See requirements.txt for the full Python dependency list (50+ packages).

Core infrastructure settings live in /opt/eas-station/.env (auto-generated by the installer):

SECRET_KEY=<64-char hex>
DATABASE_URL=postgresql+psycopg2://eas_station:<password>@127.0.0.1:5432/alerts
REDIS_HOST=localhost
REDIS_PORT=6379
DOMAIN_NAME=your-domain.com
SSL_EMAIL=admin@example.com

All feature settings (hardware, Icecast, TTS, notifications, FIPS codes, stream profiles) are stored in the database and managed through the web UI at /settings.

💡 Production SSL: The installer can provision Let's Encrypt automatically, or run sudo certbot --nginx -d your-domain.com at any time after pointing DNS.

See Changelog and Feature Roadmap for full details.

Quick diagnostics:

• SDR not working? bash scripts/collect_sdr_diagnostics.sh → SDR Quick Fix Guide
• Connection issues? bash scripts/diagnostics/troubleshoot_connection.sh

git clone https://github.com/KR8MER/eas-station.git
cd eas-station
python3 -m venv venv && source venv/bin/activate
pip install -r requirements.txt
cp .env.example .env   # edit with local DB settings
python app.py

See Contributing Guide and Code Standards.

🚨 EAS Station generates valid SAME headers and attention tones. These signals will trigger downstream EAS equipment if coupled to any RF, STL, or streaming chain.

• Not FCC-certified — for laboratory, research, and training use only.
• Never connect to on-air infrastructure without explicit authorization.
• Unauthorized broadcast has real consequences: iHeartMedia paid a $1M settlement (2015); the Olympus Has Fallen trailer misuse cost $1.9M.
• The maintainer will cooperate fully with authorities against any misuse.

See Terms of Use, FCC Compliance, and Trademark Policy.

EAS Station is dual-licensed:

Free to use, modify, and distribute under the GNU Affero General Public License v3. Modifications to network-deployed versions must be made available as source.

For proprietary or closed-source use without AGPL obligations — no source disclosure required, priority support, custom development assistance. See LICENSE-COMMERCIAL.

Copyright (c) 2025-2026 Timothy Kramer (KR8MER)
EAS Station — https://github.com/KR8MER/eas-station

Branding governed by the Trademark Policy. See NOTICE for required attribution details.

NOAA/NWS · FEMA/IPAWS · PostGIS Team · U.S. Census Bureau (TIGER/Line) · Putnam County GIS Office · Allen County GIS Office · Flask Community · RTL-SDR Project · Amateur Radio Community