In today's environment, in which WLAN technology is being deployed extensively, in order to improve the effectiveness of such deployments it is necessary to have a detailed understanding of WLAN signal characteristics. Radio signal attenuation and path losses depend on the environment and have been recognized to be difficult to calculate and predict. Past studies of the signal propagation, in both an indoor and in an outdoor environment have used several models with varying degrees of success and/ or complexity. I present here a simple analytic model for an indoor environment, and use it for determining the signal strength in a 3-D environment with one transmitter. The model is experimentally verified and is shown to yield a good match with the measurements. Several consequences of the model are studied and contour plots mapping signal strengths are generated. Signal strengths in the presence of an obstruction in the field of the transmitter are studied.