G/Tsys calculator

Updated 8 February 2016

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Antenna Diameter m
Antenna Efficiency %
Antenna Noise Temperature Kelvin dB(290K)
Operating Frequency MHz
Feed loss dB(10log)
LNB VSWR 1:
LNB Noise Figure dB(290K) or Kelvin
Calculated Gain dB
System noise temperature at antenna Kelvin dB(290K)dB(10log)
G/Tsys dB

2003 Jens T. Satre

G/Tsys= 10*log(G)-10*Log(Tsys)

alfa= 10^(FeedLoss/10)] - the antilog of the feedloss in dB (abs value).

Beta= 10^(LNBVSWRLoss/10)] - the antilog of the VSWR LNB loss in dB (abs value).

L=alfa+beta

Tsys= Tant+ 290*[L-1] + Tlnb*L

(G/T is referred to the input of the antennafeed - before WG losses)