The LNA boosts the antenna sign to overcome feed line losses concerning the antenna plus the receiver. To simplify the noise obtain calculation, the sounds sources in The straightforward amplifier circuit in Determine one could be lessened to just one overall RTI noise source (Vni, Overall), as demonstrated in Determine https://low-noise-amplifier67777.blogdon.net/rumored-buzz-on-low-noise-amplifier-53342011