# heardlog

APRS RF coverage logger and map for amateur radio digipeaters.

Collects every packet heard on RF by a Direwolf digipeater and builds an
interactive coverage map showing which Maidenhead subsquares have been reached,
which paths were used, and which stations have been heard.

Live: [aprs.sa6anw.se](https://aprs.sa6anw.se)

---

## Architecture

```
[Shack LAN]                         [DMZ]
Direwolf AGW :8000
      |
agw_forwarder.py  --POST/Bearer-->  FastAPI :8085  -->  TimescaleDB + PostGIS
                                          |
                          rotate.aprs2.net|  (APRS-IS regional feed, outbound)
                                          |
                                     nginx :80/443
                                          |
                                     index.html  (Leaflet map)
```

| Source | Table | Key data |
|---|---|---|
| Direwolf AGW (RF) | `rf_frames` | Every packet received over the air |
| APRS-IS regional | `is_frames` | Regional feed within 200 km radius |

---

## Repository layout

```
heardlog/
????????? .env.example
????????? README.md
????????? docker-compose.yml
????????? collector/               # DMZ - runs in Docker
???   ????????? Dockerfile
???   ????????? requirements.txt
???   ????????? config.py
???   ????????? db.py                # TimescaleDB schema + insert helpers
???   ????????? maidenhead.py        # Maidenhead subsquare calculations
???   ????????? aprs_is.py           # APRS-IS client
???   ????????? main.py              # FastAPI app + APRS-IS background task
????????? agw-forwarder/           # Shack - runs directly on the Direwolf machine
???   ????????? agw_forwarder.py
???   ????????? requirements.txt
???   ????????? agw-forwarder.service
????????? web/
    ????????? index.html           # Leaflet map (served by nginx)
    ????????? nginx.conf
```

---

## Getting started

### DMZ

```bash
git clone <repo> heardlog
cd heardlog

cp .env.example .env
# Edit .env - set DB_PASSWORD and API_KEY

# Generate API key
python3 -c "import secrets; print(secrets.token_hex(32))"

docker compose up -d
docker compose logs -f collector
```

Expected output:
```
INFO  db    Database schema ready
INFO  main  Startup complete - listening for RF frames
INFO  aprs_is  APRS-IS login: # logresp SA6ANW-1 unverified, server T2...
```

### Shack (agw-forwarder)

```bash
pip3 install requests

cat > heardlog/agw-forwarder/.env << 'EOF'
AGW_HOST=localhost
AGW_PORT=8000
COLLECTOR_URL=http://<dmz-ip>:8085
API_KEY=<same key as DMZ .env>
STATION_CALL=SA6ANW-1
LOG_LEVEL=INFO
EOF

# Test manually first
cd heardlog/agw-forwarder
python3 agw_forwarder.py
```

### Run as systemd services (shack)

```bash
sudo cp heardlog/agw-forwarder/direwolf.service /etc/systemd/system/
sudo cp heardlog/agw-forwarder/agw-forwarder.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now direwolf
sudo systemctl enable --now agw-forwarder
journalctl -u direwolf -u agw-forwarder -f
```

`agw-forwarder` has `Wants=direwolf.service` - systemd starts Direwolf automatically.

---

## Configuration

### DMZ (`.env`)

| Variable | Default | Description |
|---|---|---|
| `STATION_CALL` | `SA6ANW-1` | Your callsign |
| `DB_PASSWORD` | - | Postgres password |
| `API_KEY` | - | Shared secret with forwarder |
| `APRS_IS_PASSCODE` | `-1` | `-1` for receive-only |
| `APRS_IS_FILTER` | `r/58.35/14.05/200` | lat/lon/km around your QTH |
| `LOG_LEVEL` | `INFO` | `DEBUG` for per-frame logging |

### Shack (`agw-forwarder/.env`)

| Variable | Default | Description |
|---|---|---|
| `AGW_HOST` | `localhost` | Direwolf host |
| `AGW_PORT` | `8000` | Direwolf AGW port |
| `COLLECTOR_URL` | - | DMZ API URL |
| `API_KEY` | - | Same as DMZ `.env` |
| `STATION_CALL` | `SA6ANW-1` | Your callsign |

---

## Map

The map has three zoom levels:

| Zoom | Display |
|---|---|
| < 7 | One dot per Maidenhead subsquare |
| 7 - 13 | Transparent subsquare rectangles (~5 x 4.6 km each) |
| >= 14 | Individual observation points |

Clicking a square opens a popup with two tabs:

- **PATHS** - actual digipeater hops heard from that square, sorted by count. Digipeaters without a known position are shown in red.
- **STATIONS** - callsigns heard from that square. Clicking a station shows detailed statistics including distance, timestamps, and top paths.

Hovering over a path row draws the route on the map: square center to each digipeater to RX station. The RX station marker (pulsing yellow dot) shows all paths heard aggregated across all squares.

Clicking **SQUARES** in the header opens a feed of all squares sorted by most recently added, with distance from the RX station.

Popups can be dragged to move them out of the way.

---

## API

| Endpoint | Auth | Description |
|---|---|---|
| `POST /ingest/rf` | Bearer | RF frame from forwarder |
| `GET /health` | - | Liveness check |
| `GET /coverage/squares` | - | Subsquares with path and station breakdown |
| `GET /coverage/points` | - | Individual observation positions |
| `GET /coverage/digis` | - | Latest known position per callsign |
| `GET /coverage/rx-stats` | - | All paths aggregated across all squares |
| `GET /coverage/station/{callsign}` | - | Detailed statistics for one station |

Swagger UI: `http://<host>:8085/docs`

---

## Implementation notes

### AGW monitoring format
Direwolf sends `U`-frames in monitoring mode with a leading space and full
monitoring header before `\r`:

```
 1:Fm SM6MJW-9 To UXRT8L Via WIDE1-1,WIDE2-1 <UI pid=F0 Len=17 F=0 >[16:46:13]\r<info>
```

The via path is extracted with a regex between `Via ` and ` <UI`.

### Path reduction
Raw APRS paths like `SK6WW,WIDE2-1` are reduced to actual physical digipeaters
by stripping alias hops (`WIDE*`, `RELAY`, `TRACE`, `ECHO`, `GATE`). This means
`SK6WW,WIDE1` and `SK6WW,WIDE2-1` both reduce to `SK6WW` and are counted together.

### Null bytes
APRS frames can contain `0x00` bytes in the info field. These are stripped
before database insert since Postgres UTF-8 rejects null bytes.

---

## Useful queries

```sql
-- Latest RF frames
SELECT ts, src_call, lat, lon, path
FROM rf_frames
ORDER BY ts DESC
LIMIT 20;

-- Stations heard in the last 30 minutes
SELECT src_call, MAX(ts) AS last_seen, COUNT(*) AS frames
FROM rf_frames
WHERE ts > NOW() - INTERVAL '30 minutes'
GROUP BY src_call
ORDER BY last_seen DESC;

-- Coverage grid
SELECT
    ROUND(lat::numeric, 2) AS grid_lat,
    ROUND(lon::numeric, 2) AS grid_lon,
    COUNT(*) AS hits
FROM rf_frames
WHERE lat IS NOT NULL
GROUP BY grid_lat, grid_lon;
```

Access the database:
```bash
docker exec -it heardlog-db-1 psql -U aprs -d aprs
```