Antenna Range Calculator

Inputs

Choose a model. Then calculate maximum range for the chosen margin.

Units are converted internally to dBm and MHz.

Signal & Hardware

Frequency

Transmit Power

Tx Gain (dBi)

Rx Gain (dBi)

Cable Loss (dB)

Misc Loss (dB)

Losses include feeders, connectors, filters, and polarization mismatch.

Receiver & Reliability

Receiver Sensitivity (dBm) Fade Margin Target (dB) Propagation Model

The calculator solves for maximum distance where received power meets sensitivity plus margin.

Geometry & Horizon

Tx Height (m)

Rx Height (m)

k-Factor

k=1.333 is a common refraction assumption. Use 1.0 for geometric Earth radius.

Apply Horizon Cap

Two-ray and horizon settings are most meaningful for line-of-sight links.

Results will appear above this form.

Formula used

This tool uses a link budget and solves for the maximum distance.

Pr(dBm) = Pt(dBm) + Gt + Gr − Losses − PathLoss
Pr(dBm) ≥ Sensitivity(dBm) + FadeMargin(dB)

Free-space path loss

FSPL(dB) = 32.44 + 20log10(f_MHz) + 20log10(d_km)

Log-distance model

PL(dB) = PL0 + 10·n·log10(d/1m)

Two-ray ground model

Pr(dBm)=Pt+Gt+Gr−Losses+20log10(ht)+20log10(hr)−40log10(d)

Radio horizon cap

d(km) ≈ 3.57·sqrt(k/(4/3))·(sqrt(ht)+sqrt(hr))

How to use this calculator

Enter frequency and transmit power using your preferred units.
Add antenna gains and estimated losses from your RF chain.
Set receiver sensitivity and your desired fade margin.
Select a propagation model that matches your environment.
Optionally apply the horizon cap using antenna heights.
Press Calculate Range to view results and download reports.

Example data table

Scenario	Frequency	Pt	Gt/Gr	Losses	Sensitivity	Margin	Model	Notes
Short-range Wi‑Fi bridge	2.4 GHz	20 dBm	6/6 dBi	2.5 dB	-90 dBm	10 dB	Free-space	Clear line-of-sight testing link.
Urban telemetry	915 MHz	14 dBm	2/2 dBi	3.0 dB	-115 dBm	12 dB	Log-distance (n=3)	Buildings and clutter increase loss.
Rural tower to client	3.5 GHz	30 dBm	15/12 dBi	4.0 dB	-95 dBm	15 dB	Two-ray	Heights matter; horizon may limit.

Use these examples as starting points. Always validate with local measurements and regulations.

FAQs

1) What does this calculator estimate?

It estimates the maximum distance where received power can meet your sensitivity plus fade margin, using your chosen propagation model and optional horizon cap.

2) Which propagation model should I pick?

Use free-space for clear line-of-sight. Use log-distance for cluttered environments with empirical tuning. Use two-ray when antenna heights dominate and ground reflections matter.

3) Why add a fade margin?

Fade margin helps maintain performance during interference, rain, multipath, and hardware drift. Higher margins reduce range but improve reliability.

4) What losses should I include?

Include feeder and connector losses, inline filters, duplexers, lightning arrestors, polarization mismatch, and any known insertion losses in the RF chain.

5) What is the horizon cap and k-factor?

The horizon cap approximates line-of-sight limitation due to Earth curvature. The k-factor models atmospheric refraction; 1.333 is a common engineering assumption.

6) Why can two-ray results differ a lot?

Two-ray has strong dependence on antenna heights and distance. It can underpredict or overpredict if terrain, obstructions, or antenna patterns deviate from the model assumptions.

7) Is this range guaranteed in the real world?

No. Real performance depends on terrain, interference, regulations, antenna alignment, and implementation details. Treat outputs as planning estimates and validate with field tests.