RF Field Survey · Signal Terrain
Start beside your router and walk. The map paints itself from the phone's motion — strong coverage glows green, and as you move away it deepens through amber into red dead zones. Speed is measured live against a free Cloudflare backend.
Stand right at your router before you tap — that exact spot becomes the fixed centre of the map. Then Walk with phone and move outward. (Demo walk shows how it behaves.)
What's real: speed & latency are measured against
/api/download and /api/ping; the terrain colour reflects those real numbers.
Position comes from the phone's DeviceMotion / DeviceOrientation sensors
(dead-reckoning) — no floor plan, no GPS. Raw WiFi signal (dBm) still isn't exposed to browsers, so
"Signal" is a 0–100 quality index derived from measured speed. If no backend is reachable, the app
says so and falls back to a simulated field.