Tower Finder

Web application and API that helps passive radar operators find suitable broadcast tower illuminators near their location.

Given geographic coordinates, the system queries the Maprad.io transmitter database for nearby FM/VHF/UHF broadcast towers, then filters and ranks them by suitability for passive radar use.

Project Structure

backend/          Python API (FastAPI)
frontend/         React SPA (Vite)
dashboard/        Admin dashboard (React/Vite)
libs/             Git submodules
  retina-geolocator/   Bistatic passive radar geolocation solver
  retina-tracker/      Multi-target Kalman tracker with anomaly detection

Quick Start

Clone (with submodules)

git clone --recursive https://github.com/offworldlabs/Tower-Finder.git
cd Tower-Finder

# If already cloned without --recursive:
git submodule update --init --recursive

Backend

cd backend
python -m venv .venv && source .venv/bin/activate
pip install -r requirements.txt
pip install -e ../libs/retina-geolocator -e ../libs/retina-tracker
cp .env.example .env    # add your Maprad.io API key
uvicorn main:app --reload

The API runs at http://localhost:8000. Interactive docs at /docs.

Frontend

cd frontend
npm install
npm run dev

Opens at http://localhost:5173. API calls are proxied to the backend during development.

API

GET /api/towers

Parameter	Type	Required	Default	Description
lat	float	yes		Latitude (-90 to 90)
lon	float	yes		Longitude (-180 to 180)
altitude	float	no	0	Receiver altitude in metres
limit	int	no	20	Max towers to return (1–100)
source	string	no	au	Data source: au, us, ca

Response:

{
  "towers": [
    {
      "rank": 1,
      "callsign": "ATN6",
      "name": "ABC Tower 221 Pacific Highway GORE HILL",
      "state": "NSW",
      "frequency_mhz": 177.5,
      "band": "VHF",
      "latitude": -33.820079,
      "longitude": 151.185,
      "distance_km": 5.9,
      "bearing_deg": 337.5,
      "bearing_cardinal": "NNW",
      "received_power_dbm": -7.7,
      "distance_class": "Too Close",
      "eirp_dbm": 79.1,
      "licence_type": "Broadcasting",
      "licence_subtype": "Commercial Television"
    }
  ],
  "query": { "latitude": -33.8688, "longitude": 151.2093, "altitude_m": 0, "radius_km": 80, "source": "au" },
  "count": 20
}

How Ranking Works

1. Fetch all FM, VHF and UHF transmitters within 80 km from Maprad.io
2. Discard towers whose estimated received power is below −95 dBm
3. Classify each tower by band (VHF / UHF / FM) and distance suitability:
   • Too Close (< 8 km) — direct signal may overwhelm the receiver
   • Ideal (8–30 km) — best bistatic geometry
   • Good (30–60 km) — workable
   • Far (> 60 km) — fallback only
4. Rank by: band preference (VHF → UHF → FM) → distance class → signal strength
5. Return top N results

Tech Stack

• Backend: Python 3.11+, FastAPI, httpx
• Frontend: React 18, Vite, Leaflet
• Data source: Maprad.io GraphQL API (ACMA RRL, FCC ULS, ISED SMS)