Fresnel Zone Calculator – LinkZoneTools
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Fresnel Zone Calculator — Terrain Profile & LOS Analysis
Fresnel Zone Calculator
Enter GPS coordinates for both sites (address geocoding is optional). Terrain elevation is retrieved automatically from free open-source datasets. Add manual obstructions for trees or buildings not captured by terrain data.
⚠ Important: Terrain elevation from SRTM/ASTER APIs (ground surface only, 30-90m resolution). Does not include buildings or vegetation. Verify antenna heights with a physical site survey before procurement.
⚠ This tool: Fresnel Zone Calculator — Terrain elevation from SRTM/ASTER 30–90m APIs. Does not include buildings or vegetation. Always conduct a physical site survey before specifying antenna heights.
Site A — Transmitter / End 1
Site A Coordinates
Address or Place Name
?
Latitude (°)
?
Longitude (°)
?
Antenna Height Above Ground
?
m
Site B — Receiver / End 2
Site B Coordinates
Address or Place Name
?
Latitude (°)
Longitude (°)
Antenna Height Above Ground
?
m
Antenna Height Units
Link Parameters
Frequency ?
?
GHz
Fresnel Clearance Target
?
Manual Obstructions (Trees / Buildings)
?
Terrain Profile Samples
?
Fetching terrain elevation data, please wait…
Elevation Data Sources (free & open, no API key required):
1st: Open-Meteo (SRTM 90m, global) · 2nd: OpenTopoData SRTM 30m · 3rd: ASTER GDEM 30m.
All use WGS84 datum. Ground surface only — add manual obstructions for trees/buildings.

Address fields are optional — you can enter GPS coordinates directly without geocoding.
🗻

Enter Two Locations & Frequency

Enter or geocode coordinates for both sites, set your antenna heights and link frequency, then click Analyze Path to generate the terrain profile and Fresnel zone clearance analysis.

Path Profile & Fresnel Zone — Site A to Site B

Line of Sight 1st Fresnel Zone (upper) Terrain Obstruction

Antenna Height Recommendations

Scenario Site A Height AGL Site B Height AGL Fresnel Clearance Status

First Fresnel Zone Radius Along Path

Point Along Path Distance from A F1 Radius 60% F1 (min clear) Terrain Elev. LOS Height Clearance

⚠ Important — Please Read Before Using This Tool

LinkZoneTools LLC · Fresnel Zone Calculator · Terms of Use & Disclaimer

📋 Reference & Educational Use Only

This tool is provided for reference, planning, and educational purposes only. It is not intended to constitute, and shall not be construed as, professional RF engineering advice or a guarantee of wireless link performance. Results are estimates based on theoretical models and published data.

⚠ Tool-Specific Notice — Fresnel Zone Calculator

Terrain elevation data is sourced from third-party APIs (SRTM 90m / OpenTopoData / ASTER GDEM) representing ground surface only — buildings, tree canopy, and above-ground obstructions are NOT included. Resolution is 30-90 meters which may miss narrow ridges or point obstructions. Antenna height recommendations must be verified against an actual site survey before tower construction or equipment procurement.

🌐 Third-Party Data & APIs

Some LinkZoneTools tools use third-party data sources including OpenStreetMap geocoding, Open-Meteo elevation API, OpenTopoData, and ASTER GDEM terrain data. LinkZoneTools LLC does not control these sources and makes no warranty as to their accuracy, availability, or currency.

⚖ Limitation of Liability — No Warranty

LINKZONETOOLS LLC PROVIDES THIS TOOL "AS IS" WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. LINKZONETOOLS LLC SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR EXEMPLARY DAMAGES ARISING FROM USE OF OR RELIANCE ON THIS TOOL, INCLUDING FAILED WIRELESS LINK DEPLOYMENTS, EQUIPMENT LOSSES, LOST REVENUE, OR BUSINESS INTERRUPTION. THE USER ASSUMES ALL RESPONSIBILITY FOR FINAL DESIGN DECISIONS AND THEIR OUTCOMES.

👤 User Responsibility

By using this tool, you acknowledge that: (1) you will independently verify all outputs against current authoritative sources; (2) you will use manufacturer link planning software as the final design authority; (3) you will conduct a physical site survey before specifying equipment or antenna heights; and (4) LinkZoneTools LLC bears no responsibility for any errors, omissions, or outcomes resulting from use of this tool.

LinkZoneTools LLC · Sarasota, FL · linkzonetools.com
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📅 Tool last reviewed: June 2026
⚠ Reference & Educational Use Only — Terrain elevation from SRTM/ASTER APIs (ground surface only, 30-90m resolution). Does not include buildings or vegetation. Verify antenna heights with a physical site survey before procurement. LinkZoneTools LLC makes no warranty as to accuracy. 📅 Last reviewed: June 2026

📚 How the Fresnel Zone Calculator Works

What does this tool do?

This tool shows whether a wireless link between two points has a clear path through the terrain. Radio signals spread out in an egg-shaped zone around the direct line. Objects near (but not in) this zone can still block your signal.

Key concepts

  • Line of sight: Can you draw a straight line between antennas without hitting terrain?
  • Fresnel zone: The elliptical zone around the path. You need 60% of this clear for a good link.
  • Earth bulge: The Earth’s curvature causes terrain to rise between distant points — even flat ground has significant rise over long paths.

How to use it

Enter both site coordinates, set antenna heights, and click "Generate Path Profile." The tool fetches real terrain data and shows exactly where obstructions exist. Red segments need to be cleared by raising antennas.

⚠ Ground surface only. Buildings and trees are not included in the elevation data. Add 5–15 m margin for vegetation in forested or suburban areas.