In the fall of 1995, a unique unattended ground sensor experiment was conducted at the Nevada Test Site. In the experiment, a variety of electro-mechanical equipment was operated, while data was gathered using a number of different types of unattended sensors at different locations. The sensors in this study included seismometers, accelerometers, electric dipole sensors, magnetometers and microphones. In this paper, the authors present some key results form the signal processing of the data from this experiment. The goal of the signal processing was to quantify some of the effects of range on signal propagation, and to determine the ability to detect signals from the equipment, to identify the equipment and to locate the equipment. Some of the physical phenomenon which can affect unattended ground sensor performance will be discussed. The paper will also include a discussion of how the geophysical site characteristics can affect the performance of unattended ground-deployed sensors. While data from a number of different types of sensors were gathered in this experiment, in this paper the authors concentrate on physical phenomenon which can affect seismic sensors and the processing of seismic data