Engineering & mechanics
Fresnel zone clearance
Find a radio Fresnel-zone radius at a point along a path.
A clear answer. Here’s how.
Uses rₙ=√(nλd₁d₂/(d₁+d₂)), with distances converted to metres. Returns the geometric zone radius and your requested fraction of it. Clearance percentage is an input, not an assurance of link performance. Does not include terrain height, Earth curvature, atmospheric refraction, diffraction loss or antenna pattern.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Frequency (GHz)
- 5
- Transmitter to obstacle (km)
- 1
- Obstacle to receiver (km)
- 1
- Fresnel zone order
- 1
- Requested percentage of zone radius
- 60
Example result
- Zone radius at obstacle (m)
- 5.47533065668
- Requested radius clearance (m)
- 3.28519839401
- Path length (km)
- 2