Radio Tomographic Imaging (RTI) is a new method for tracking and localizing moving objects within an area surrounded by wireless nodes. Signal blockage caused by one or multiple objects (i.e. a person) will attenuate the Received Signal Strength (RSS). In this paper, we experimentally present the limits where RTI may not operate properly, taking into account some of the main parameters such as number of nodes, channel, area, number of pixels, power of transmission and calibration time. Since RTI is an ill-posed problem, we use a simplified linear model using Tikhonov’s regularization for image reconstruction. Kalman filtering allows to keep track of moving objects, hence the average error and its limits.