LoS Link Check & Fresnel Zone

Validate any wireless link
before you climb the tower.

GridVisio's LoS Link Check gives you an instant terrain cross-section with the first Fresnel zone, obstruction detection, bearing, and free-space path loss — for any two map points. Three elevation sources including USGS 10m for the US. Export as PDF or PNG.

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LoS Link Check with Fresnel zone overlay

Everything you need to validate a link

Click any two points on your coverage map — tower to subscriber, hypothetical site to cluster, or any two custom pins. The analysis runs in seconds.

Terrain cross-section

Elevation profile between any two map points using real terrain data. See exactly where the path rises above line-of-sight.

First Fresnel zone

The Fresnel ellipsoid is overlaid on the terrain profile. Any intrusion into the first zone is flagged as an obstruction — stricter than line-of-sight alone.

Instant verdict

Clear or obstructed, at what distance the obstruction occurs, and the free-space path loss in dB. Compare results across three elevation sources.

Export PDF or PNG

Generate a clean PDF or PNG of the terrain profile, Fresnel zone, and link details. Share with clients or attach to grant documentation.

Save links on the map

Save LoS links with custom colour, line style, and width. Saved links are visible alongside towers and subscribers on your coverage map.

Three elevation sources

SRTM 30m (global default), ASTER 30m (global alternative), and USGS NED 10m (continental US, highest precision).

Validate from a hypothetical tower site

Drop a hypothetical tower pin anywhere on the map, then use the LoS tool to check links from that location to any subscriber or point. Evaluate a potential site before committing to installation.

The Reach Estimate panel shows how many unserved subscribers fall within the configured radius and beamwidth — live as you adjust parameters. Promote to a real tower with one click when you're confident.

LoS link popover showing distance, bearing, and link parameters

LoS link parameters — distance, bearing, frequency, antenna heights

LoS powers the lead widget too

The same LoS engine that powers the map tool also runs inside the coverage widget embedded on your website. When a visitor checks their address, GridVisio runs a real LoS analysis to your nearest towers — not just a polygon overlap.

The lead you receive is already qualified: you know which tower serves them, whether the path is clear, and the free-space path loss before you make the first call.

GridVisio layers panel — towers, coverage, subscribers, links, white areas all toggleable

Layers panel with LoS links visible

Frequently asked questions

What elevation data does the LoS checker use?

Three sources: SRTM 30m (global default), ASTER 30m (global alternative), and USGS NED 10m (continental US only — highest resolution for US deployments). Choose per analysis.

What is the Fresnel zone and why does it matter?

The Fresnel zone is an ellipsoid around the line-of-sight path. For reliable radio performance, the first Fresnel zone must be at least 60% clear. A link can appear line-of-sight but still be degraded if terrain intrudes into the first Fresnel zone.

Can I check LoS from a hypothetical tower location?

Yes. Drop a hypothetical tower pin anywhere, then use the LoS tool to check links from that location to any subscriber or point.

Does the LoS tool account for antenna height?

Yes. Set antenna height at both endpoints. The terrain clearance check is calculated from the antenna height above ground, not ground level.

Can I export the LoS analysis for a grant application?

Yes. Export PDF or PNG for a clean report including the terrain profile, Fresnel zone, link parameters, and verdict — useful for BEAD and other broadband grant applications.

Validate any wireless linkbefore you climb the tower.