RF Link Budget Calculator
EIRP · FSPL · noise floor · SNR · link margin · range sweep
Link parameters
Link preset
— current design —
WiFi 2.4 GHz point-to-point
LoRa 868 MHz
LEO satellite downlink 2.2 GHz
Microwave backhaul 18 GHz
Frequency
MHz
GHz
Distance
km
mi
TX power (dBm)
TX feedline loss (dB)
TX antenna gain (dBi)
RX antenna gain (dBi)
RX feedline loss (dB)
Extra path losses (dB)
Fade margin req. (dB)
RX noise figure (dB)
Receiver bandwidth
Hz
kHz
MHz
Required SNR (dB)
Temperature (K)
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Free-space model. Math: FSPL = 32.45 + 20·log₁₀(f
MHz
) + 20·log₁₀(d
km
); EIRP = P
tx
− L
feed
+ G
tx
; noise floor = 10·log₁₀(kT·1000) + 10·log₁₀(BW) + NF (k = 1.380649×10⁻²³); sensitivity = noise floor + required SNR; link margin = SNR − required SNR − fade margin. Fresnel zone-1 radius r₁ = √(λ·d₁·d₂ / (d₁+d₂)) at midpath — keep ≥ 60 % of it clear. Max range is the analytic FSPL inversion at zero margin (fade margin included).
Budget waterfall
Node
Δ dB
Level dBm