Irradiance data were collected over a 1km horizontal terrestrial path using several different sized receiving apertures. The data were collected under moderate-to-strong turbulence conditions. The receiver system consisted of a 154mm (6") refracting telescope outfitted with several removable apertures. The path was instrumented with three 3-axis anemometers and three scintillometers, two of which were capable of measuring the inner scale of turbulence in addition to Cn2. Histograms were formed with the data and compared to the Log-Normal and Gamma-Gamma PDF models. As expected, neither PDF model was applicable under all conditions of aperture averaging. Hypotheses are made as to why the models were unable to completely capture the effects of aperture averaging on received irradiance data.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.