Friis formula

The Friis formula permits to calculate the distance between the transmitter and the receiver.

<applet code="friis.class" archive="friis.jar" width="500" height="1000"></applet>


Applet owner erg2332
Applet identifier friis
Applet title Friis formula
Applet description The Friis formula permits to calculate the distance between the transmitter and the receiver.
Applet credits Eduardo Reyes, 2013 11 22
Applet font name Bitstream Vera Sans Mono
Applet font style 0
Applet font size 18
Applet html width 500
Applet html height 1000
Applet data number 14
Applet results number 8

Variable 1 f
Label 1 f [Hz]
Description 1 f
Initial value 1 100E6
Variable 2 FPP
Label 2 FPP [1/1]
Description 2 Polarization loss factor
Initial value 2 1
Variable 3 Vg
Label 3 Vg [V]
Description 3 Vg
Initial value 3 15
Variable 4 Rg
Label 4 Rg [ohm]
Description 4 Rg
Initial value 4 5
Variable 5 Xg
Label 5 Xg [ohm]
Description 5 Xg
Initial value 5 -21.25
Variable 6 Rit
Label 6 Rit [ohm]
Description 6 Rit
Initial value 6 36.5
Variable 7 Xit
Label 7 Xit [ohm]
Description 7 Xit
Initial value 7 21.25
Variable 8 Gt
Label 8 Gt [1/1]
Description 8 Gt
Initial value 8 3.28
Variable 9 Vca
Label 9 Vca [V]
Description 9 Vca
Initial value 9 1E-3
Variable 10 Rir
Label 10 Rir [ohm]
Description 10 Rir
Initial value 10 36.5
Variable 11 Xir
Label 11 Xir [ohm]
Description 11 Xir
Initial value 11 21.25
Variable 12 Rl
Label 12 Rl [ohm]
Description 12 Rl
Initial value 12 100
Variable 13 Xl
Label 13 Xl [ohm]
Description 13 Xl
Initial value 13 -21.25
Variable 14 Gr
Label 14 Gr [1/1]
Description 14 Gr
Initial value 14 3.28

Variable 1 lambda
Label 1 lambda [m]
Description 1 Wavelength
Formula 1 3E8/f
Variable 2 Pdt
Label 2 Pdt [W]
Description 2 Available power of the transmitter
Formula 2 (1.0/8.0)*pow(abs(Vg),2)/Rg
Variable 3 Kt
Label 3 Kt [1/1]
Description 3 Impedance mismatch losses in the transmitter
Formula 3 1-(pow(Rit,2)-2*Rit*Rg+pow(Rg,2)+pow(Xit,2)+2*Xit*Xg+pow(Xg,2))/(pow(Rit,2)+2*Rit*Rg+pow(Rg,2)+pow(Xit,2)+2*Xit*Xg+pow(Xg,2))
Variable 4 Pet
Label 4 Pet [W]
Description 4 Delivered power of the transmitter
Formula 4 Pdt*Kt
Variable 5 Pdr
Label 5 Pdr [W]
Description 5 Available power of the receiver
Formula 5 (1.0/8.0)*pow(abs(Vca),2)/Rir
Variable 6 Kr
Label 6 Kr [1/1]
Description 6 Impedance mismatch losses in the receiver
Formula 6 1-(pow(Rl,2)-2*Rl*Rir+pow(Rir,2)+pow(Xl,2)+2*Xl*Xir+pow(Xir,2))/(pow(Rl,2)+2*Rl*Rir+pow(Rir,2)+pow(Xl,2)+2*Xl*Xir+pow(Xir,2))
Variable 7 Per
Label 7 Per [W]
Description 7 Delivered power of the receiver
Formula 7 Pdr*Kr
Variable 8 distance
Label 8 distance [m]
Description 8 Distance between transmitter and receiver
Formula 8 (1.0/4.0)*sqrt(Per*FPP*Kt*Kr*Gt*Gr*Pdt)*lambda/(Per*PI)

Return