At present the testing of power amplifiers within base station transmitters is limited to testing at component level as opposed to testing at the system level. While the detection of catastrophic failure is possible, that of performance degradation is not. This paper proposes a base station model with respect to transmitter output power with the aim of introducing system level monitoring of the power amplifier behaviour within the base station. Our model reflects the expected output levels of second or third generation CDMA base stations conforming to the Open Base Station Architecture Initiative (OBSAI) open base station reference architecture. The simulated base station output power is verified by comparison to field data using such metrics as power complementary cumulative distribution function (CCDF), volatility, absolute deviation, mean absolute deviation and rate of change.