GPS L1 Link Budget
Satellite Tranmitter
Transmitter Power (25 Watts) 14.25 dBW
RF Losses in trasmitter path -1.25 dB
Antenna Gain (with respect to an isotrope) 13.5 dBi
Satellite EIRP (wrt isotropic radiator) 26.50 dBW 446.68 Watts
Propagation
Atmoshperic and Polarization Losses -0.5 dB
where d = distance from antenna = 2.52E+07 meters
c = speed of light = 3.00E+08 m/sec
f = frequency = 1.58E+09 Hz
lambda = wavelength = c/f = 1.90E-01 meters

= -10log10 3.17E+08 1.90E-01
= -10log10 1.67E+09

Free Space Path Loss over Distance -184.43 dB
Received Power on Earth -158.43 dBW
-128.43 dBm 1.44E-04 pW
Gain of Receive Antenna 38 dBic
RF losses in 300 feet of LMR400UF cabling and
connectors from Receive Antenna to Line Amplifier -6.7 dB
Gain of Line Amplifier 20 dB
RF Power at Input to Re-Radiating Antenna -77.13 dBm 19.36 pW
Gain of Passive Re-Radiating Antenna 3 dBic
Re-Radiated EIRP (wrt isotropic radiator) -74.13 dBm 38.64 pW
Re-Radiated ERP (wrt dipole radiator) -76.28 dBm 23.55 pW
= λL o s sP a t h
24






=
λ
pi d
L o s sP a t h














×−=
2
10
4log10 λ
pidLossPathSpaceFree
2
2
where d = distance from antenna = 100 feet

= -10log10 383.023 1.90E-01
= -10log10 2.01E+03

Free Space Path Loss over Distance -66.07 dB
RF power level at 100 ft distance = -140.20 dBm wrt isotropic antenna
-142.35 dBm wrt dipole antenna














×−=
2
10
4log10 λ
pidLossPathSpaceFree
2
2