Friis Equation

Friis equation calculates the received power from an antenna at some distance given a transmission frequency and antenna gains.

The subject of the equation can be changed to find the distance R, between two antennas as shown below;

where,

  • = Receiver Efficiency
  • = Impedance Mismatch Coefficient
  • = Polarization Coefficient
  • Pth = Chip Threshold Power
  • Pr = Receiver Power
  • Gr = Receiver Antenna Gain
  • Gt = Transmitter Antenna Gain

Friis Distance Calculator

Enter the correct values of the variables in the input boxes provided below to calculate the distance R, between antennas.

N/B : Enter only numbers

Distance, R: ?