Techniques for monitoring transmission performance of a satellite communications systems are provided, including techniques for measuring the primary contributors to the end-to-end SNR, including the uplink SNR, the downlink SNR, and the C / I for each link in the network. These individual measurements are used to estimate satellite effective isotropic radiated power (EIRP), satellite antenna gain-to-noise-temperature (G / T), and loss due to an Earth Terminal pointing error. The EIRP, satellite antenna G / T and loss due to Earth terminal pointing error may then be used to determine operating parameters for the satellite communications network that enable the network to operate more efficiently.