Secondary multiple-access interference processes are characterized for multi-hop packet radio networks, in which users are assumed to be Poisson-distributed in the plane and to use frequency-hopped spread-spectrum signaling with a receiver- oriented assignment of frequency-hopping patterns. The throughput per node and the average forward progress are then evaluated for frequency-hopped multi-hop networks which employ (i) random forward routing with fixed transmission radius (RFR) and (ii) most forward progress routing with fixed transmission radius (MFR). The optimal average number of neighbors and transmission radius are derived for these cases when Reed-Solomon forward- error-control coding with minimum distance decoding or binary convolutional coding with Viterbi decoding is employed.