Start at the installed antenna, not at a nominal connector. Include gain versus elevation, polarization and ground-plane effects; then place every passive loss, LNA, filter, protection device, bias tee, splitter and cable in physical order. Loss before the first effective LNA raises cascaded noise directly, while downstream loss may be tolerable if preceding gain is stable and linear.
Calculate minimum and maximum path states across frequency, temperature, supply and component tolerance. Check LNA gain and noise, filter insertion loss and rejection, cable loss and return loss, receiver input range, AGC or ADC headroom, compression and recovery under nearby transmitters. More gain is not automatically better when it removes blocker headroom.
For an active antenna, add bias voltage and current, inrush, open- and short-circuit detection, ESD or surge boundary and fault response. Identify the RF reference plane used for receiver sensitivity and the installed plane used for system acceptance so that cable loss and active gain are neither omitted nor counted twice.