Low-Earth-orbit store-and-forward satellites in the amateur radio service

The authors review the current state of the art in amateur radio store-and forward satellite communications. Several operating satellite systems are described along with the procedures, equipment, and software required to access them. For PACSAT-1 empirical data have been used to estimate a downlink bit error probability of 6.0E-5. A further description of downlink performance is given through the examination of data-link layer frame retry rates encountered during file downloading operations. Typical examples of characteristics of downlink signal fading are given for PACSAT-1. A breakdown of downlink usage by data type is given for PACSAT-1. To show how the PACSAT-1 and UoSAT-5 satellites are utilized on a day-to-day basis, graphical summaries of two weeks of PACSAT-1 and three weeks of UoSAT-5 operation are included