Inputs
Location A
Location B
RF / Atmosphere
Notes:
- "Reach" circles use radio horizon (distance to horizon) for each site, not guaranteed coverage.
- LOS check includes Earth curvature (k-factor) but no terrain/obstructions.
- Fresnel zone 1 clearance requires a frequency — enter MHz above to enable it.
- Optional power shows free-space received power estimate (isotropic unless you enter dBi gain).
Results
Enter values and click Calculate.
Top-down Overlapping Reach (Circles)
A reach
B reach
overlap
not to geographic scale (diagram)
Profile View (Earth Curve + Towers + LOS)
Earth curve uses effective radius (k-factor)
line = straight LOS path
Fresnel zone 1
What's being computed
- Great-circle distance (Haversine)
- Radio horizon per site:
d ≈ √(2·Reff·h) - Earth bulge along the path:
b(x)=x(d-x)/(2·Reff) - Clearance: LOS height − bulge (sampled along path)
- Fresnel zone 1 radius:
F₁(x) = √(λ·d₁·d₂/d)where d₁, d₂ are distances from each end - Fresnel margin: clearance − F₁ radius at each point; worst case reported
- Optional FSPL & received power estimate if Tx power is provided