Fresnel Zone Calculator

Find the radius of the first Fresnel zone of a radio link.

Distance to point 1

Distance to point 2

Frequency (GHz)

First Fresnel zone radius 17.667

Formula: r = 17.31·√(d₁·d₂ ÷ (f·(d₁+d₂)))

Step-by-step with your numbers:

1. Values used:

2. Distance to point 1 = 5

3. Distance to point 2 = 5

4. Frequency = 2.4 GHz

6. First Fresnel zone radius = 17.667

Did we solve your problem today?

The Fresnel zone is the elliptical region around a radio path that must stay clear of obstacles.

The math behind it

r = 17.31·√(d₁·d₂ ÷ (f·(d₁+d₂))) in metres, with distances in km and frequency in GHz.

5 km + 5 km at 2.4 GHz → about 17.7 m radius at midpoint.

How much must stay clear?

Keep at least 60% of the first Fresnel zone unobstructed for a reliable link.