Fresnel zone clearance
First Fresnel-zone radius at a point along a radio path.
First-zone radius--
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Fresnel Zone Clearance Calculator
Calculate first Fresnel-zone radius and recommended 60 percent clearance along a radio path.
About this calculator
How to use it
Set the frequency, total path distance and measurement point to calculate the first Fresnel-zone radius.
Understanding the result
Good line of sight is not always enough. Aim to keep at least 60 percent of the first Fresnel zone clear of terrain and structures.
More ham radio calculators
Use this calculator as a practical starting point. Check critical radio, electrical and installation work with suitable test equipment and current licence requirements.