The development of a model to estimate the bistatic transmission loss associated with intersystem interference

This paper presents a new method for evaluating transmission loss, which is a key factor used in determining the impact of interference between terrestrial radio relay systems and Earth-satellite systems operating at the same frequency. The current model used by the CCIR was developed in the early 1970´s when system packing density was low and large earth station antennas allowed the consideration of narrow beam approximations, resulting in a small common volume of intersection of the two beams. The recent increase in microwave communications traffic and improvements in technology have meant that smaller earth station antennas, including very small aperture terminals (VSATs), can be employed and hence the model requires revision. Results from the new model proposed are compared with two experimental geometries and good agreement is found