Use this tool to check whether an RF transmitter and receiver have line-of-sight. Click the map to set a station — first Station A, then Station B — and drag either pin to fine-tune.
Click map to place:
ANot set — click the map
BNot set — click the map
Fresnel footprint ⓘ
Add obstructions
Trees, buildings, ridgelines — anything not in bare-earth data.
Drawn obstructions
STATION A
STATION B
Elevation data via Open-Meteo (Copernicus DEM, ~30m resolution), with Open-Elevation as backup. Antenna heights above are always used, however you set the coordinates.
Result
Drag either antenna marker (amber = A, red = B) up or down to adjust its height — the analysis updates live as you release.
Click the map to place the base, then click again to place the intruder. Drag either marker to reposition — adjust velocity and altitude to see time-to-base, and optionally overlay an interceptor's pursuit profile.
Place a base, then add interceptor positions (each covers a 20km-diameter area) — click "Optimize" to lay them out automatically, or place them by hand. Whichever position is closest to the intruder responds.
Click map to place:
BNot set — click the map
TNot set — click the map
— km—— min to base
Altitude: 1500 m
No position in range
Time to intercept: —
55 m/s
1500 m
60 m/s
000°
Terminal phase (tail chase) is auto-set to 70 m/s. Turn rate is notionally 360° in 12s, so the 180° J-turn after passing the target takes 6s (plus a 2s reaction delay). If the target is already closer to base than the launch point, there's no pass to make — it's a straight pursuit with no J-turn. Turn arcs on the map are drawn at a visible size for clarity — the real turn radius at these speeds is only ~100–300m, too small to see against the range rings.