Line of Sight Calculator

Calculate radio horizon and assess signal path clearance for wireless links. This tool helps engineers, technicians, and RF planners determine if a direct line of sight exists, accounting for Earth’s curvature and atmospheric refraction.

Path Parameters

Calculated Results

Line of Sight Distance ($d_{los}$): --

Radio Horizon ($d_r$): --

1st Fresnel Zone Radius: --

Fresnel Clearance at Midpoint: --

Drag the slider to adjust the obstacle's height.

Obstacle Height: 0m

How It Works: The Formulas Behind LOS

Visual Line of Sight

The maximum distance to the horizon from an antenna at height ($h$):

$$d_{los} = 3.57\sqrt{h}$$

(where $d_{los}$ is in km and $h$ is in meters)

Radio Horizon

Radio waves bend with Earth's curvature, extending the range beyond the visual horizon:

$$d_r=4.12\sqrt{h}$$

(where $d_r$ is in km and $h$ is in meters)

The Fresnel Zone

A clear ellipsoidal area around the direct path is required. Obstructions here cause attenuation. The radius ($r$) at midpoint is:

$$r = 17.32\sqrt{\frac{d}{4f}}$$

(where $r$ is in meters, $d$ is in km, and $f$ is in GHz)

Ideally, ensure at least **60% clearance** of the first Fresnel Zone.

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Engineering checks for Line of Sight Calculator

Before using Line of Sight Calculator in a PCB, firmware, repair, or validation workflow, confirm the details that usually decide whether the design works reliably instead of only reading the headline specification.

Design and troubleshooting checklist

AreaWhat to checkWhy it matters
Formula inputsCheck the units, tolerance, and boundary values used by the line of sight calculator between two points calculationWrong units or ideal assumptions can make a correct formula misleading
Circuit contextCompare the result with voltage, current, power, thermal, and safety limits on the PCBCalculator output still needs board-level validation
VerificationConfirm the result with datasheet limits, simulation, or bench measurement before releaseMeasured behavior catches parasitics and loading effects

These checks help connect the search intent around line of sight calculator between two points with practical board-level decisions, component selection, and failure analysis.

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