Linear microcells employing low base station antennas have been proposed for emerging PCS systems. In such systems, the characteristics of the propagation on line-of-sight (LOS) radio links will fundamentally determine the system performance. In this context, it is meaningful to discuss the effect on system design of the two commonly used propagation models, the two-slope model and the single-slope model. In this paper we present several methods to compare the frequency reuse pattern and base station separation based on these two propagation models, and verify the importance of correct propagation modeling for efficient system design. We consider interfering signals coming from two cochannel base stations in the first tier, and include slow fading loss when comparing system performances. Based on system design results and subsequent performance, the two-slope model is recommended for LOS PCS microcells.