Microsoft Corporation builds many wireless devices, including the Surface tablet. These devices connect to a variety of wireless networks and often operate in an interior environment where building structures (e.g. walls, floors) interfere with signal propagation. The Microsoft Surface Clinic team is characterizing the impact of interior environments (e.g. hallways, walls, floors) on RF propagation at commonly used WiFi and cellular data bands. From their experiments, the team developed a revised model for predicting path loss in a variety of indoor environments.