This month we finish the satellite tracking program by W6WNK as modified by WA6DLI. It was run in installments as it is quite a long program. The underlying program was distributed by AMSAT when the ZX81 was the official AMSAT computer. Bob modified the program when N6VMO, John, asked for any Timex satellite tracker so he could put his to use. It is very instructive to see the tricks used to straighten out dates in this program. It has been modified for OSC-13 with the latest parameters included. G2 has also been amended to cover the sidereal parameters for later years.