RF Link Budget Calculator

Link-budget calculation emerged from the satellite-communications industry in the 1960s. Arthur C. Clarke\'s 1945 paper proposing geosynchronous-orbit communications satellites could only be realized after engineers methodically accounted for every dB of signal loss between Earth and space and back — TX power, antenna gains, atmospheric attenuation, rain fade, polarization mismatch, feed losses, and receiver noise figure all summed to produce a predicted carrier-to-noise ratio.

The Intelsat I satellite (1965) was the first commercial satellite with a documented link budget in its engineering manuals; subsequent NASA deep-space missions pushed the technique to extremes — Voyager 1\'s 23W transmitter is received on Earth at -175 dBm through 70m dishes, with every step of the link documented in the mission plan.

Today every wireless product — WiFi router, cellular base station, Bluetooth speaker, IoT sensor — ships with a link budget showing expected range vs. environment. The basic equation (P_tx + G_tx − L_path + G_rx = P_rx) has not changed since 1946.

Enter the 8 link parameters: TX power (typically 10-30 dBm for consumer gear, up to +50 dBm for cellular), antenna gains (0-30 dBi depending on type), cable losses (typically 0.5-3 dB), frequency and distance (FSPL computed automatically), and receiver sensitivity (typically -80 to -120 dBm).

For a reliable outdoor link, target ≥ 20 dB total margin. For critical mission links (SAR beacons, satellite uplinks), target ≥ 40 dB. The waterfall visualization shows each term on a dB bar so you can spot which parts of the budget are eating your margin. Everything runs client-side.