Friis Equation

Calculate Received Power (Pr) in wireless links.

RECEIVED POWER (Pr): 0 dBm Path Loss: 0 dB

What is the Friis Transmission Equation?

Formulated by Danish-American radio engineer Harald T. Friis in 1946, the Friis Transmission Equation is a vital formula in telecommunications. It calculates the power received by an antenna under idealized conditions given another antenna some distance away transmitting a known amount of power. It is the mathematical foundation for establishing point-to-point wireless links, Wi-Fi bridges, and satellite communications.

Understanding Link Budgets and Path Loss

To establish a stable wireless connection, the received signal must be stronger than the receiver's minimum sensitivity threshold. Our calculator performs a "Link Budget" analysis. First, it calculates the Free Space Path Loss (FSPL) based on the distance (km) and frequency (GHz). Higher frequencies and longer distances result in massive signal attenuation. Then, it takes your transmit power (dBm), adds the gain of both your transmitting and receiving antennas (dBi), and subtracts the Path Loss to give you the final Received Power (Pr) in dBm.

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AI-generated estimates. No guarantee of accuracy. We assume no liability for decisions based on these results. Independent verification is recommended.