Important Disclaimer: Results are based on public SRTM elevation data.
The tool considers terrain only - it does NOT account for buildings, trees, vegetation, or man-made obstacles.
Field verification is required before deploying any link.
1Upload your links CSV
Required columns:
NE, FE, NE Lat, NE Long, FE Lat, FE Long, NE Height (m), FE Height (m), Frequency (GHz)
2Run Analysis
After a valid CSV is uploaded, this button will be enabled.
Output Legend
Green Route = Clear
Required clearance met at every sampled point.
Orange Route = Critical
The ray passes over the terrain, but the Fresnel zone is cut - expect diffraction loss.
Red Route = Obstructed
Terrain rises above the direct ray - no line of sight.
Blue Pin = Site
How the analysis is calculated
Terrain sampling. Every 40 m for links up to 30 km, every 100 m beyond that.
Elevations are bilinear-interpolated from SRTM tiles. Earth curvature.bulge = d1 x d2 / (2 x k x 6371) x 1000 metres, added to the terrain so the ray stays straight. Fresnel radius.F1 = 17.32 x sqrt( d1 x d2 / ( f x (d1+d2) ) ) metres, with d in km and f in GHz. Required clearance.required = max( F1 x pct/100 , minimum clearance ) - whichever is larger governs.
The Fresnel term governs mid-path; the minimum clearance governs near the towers where F1 shrinks to zero. Clearance and margin.clearance = ray - (terrain + bulge) and margin = clearance - required. Verdict. Obstructed if clearance < 0, Critical if margin < 0, otherwise Clear. Diffraction loss. Estimated with the ITU-R P.526 knife-edge model. 0 dB at 60% of F1, about 6 dB at grazing.
A broad or rounded ridge loses more than a knife edge. Accuracy. SRTM is roughly ±16 m vertically and models bare terrain only - no buildings or vegetation.
These results rank links for survey; they do not approve them.