Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For Students · Radio Range

Radio Range for a building collapse

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a building collapse live below — adjust the inputs and watch it respond, right in your browser.

Radio Range / Link BudgetLive

VHF/UHF horizon + path loss

Estimated usable range

9.7mi

Controls

Presets

Base antenna (ft)

Portable height (ft)

Power (W)

Frequency (MHz)

Rx sensitivity (dBm)

Combines the radio horizon (1.23·(√h₁+√h₂), feet→miles) with a free-space link budget (EIRP minus path loss vs receiver sensitivity). Actual range depends on terrain, foliage, and buildings — treat this as a best-case planning estimate.

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Data Inspector

Radio horizon9.7 mi

Link budget147 dB

Limited byline-of-sight

Governing equation

FSPL = 20 lo g_{10} (\frac{4 π d}{λ}) = 147 dB (d = 9.7 mi, f = 155 MHz)

Reading this result: Range is capped by the horizon at 9.7 mi — raising the base antenna helps more than adding power here.

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Also for:Researchers Educators Engineers Hobbyists & Makers K-12 Students First Responders General version →

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Frequently asked questions

Is this good for students?: Yes — this version of "Radio Range for a building collapse" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.