A primary challenge in SDI systems is to transfer information reliably from sensors and within the battle management system. The volatile, hostile environment associated with an SDI system may include multiple-hop communications through channels with anomalous propagation conditions in the face of jamming and multiple-access interference. This paper addresses multiple-hop communications system performance in the face of such disturbances. A systems viewpoint is taken by postulating an SDI configuration involving multiple nodes, which may consist of sensors, weapons platforms, and battle management stations as well as hostile platforms such as jammers. A computer model is used to set up the geometry as well as to evaluate link ,performance parameters such as carrier-to-noise ratio (CNR), jamming-to-signal ratio (JSR), and bit error rate (BER). These can then be used to evaluate derived parameters such as packet error probabilities, packet delay, and throughput. Thus, conditions under which the system is potentially stressed can be considered in a direct manner, and alternative means to alleviate the sytem degradation can be considered.