As a former AT&T Mgr. satellites were not used in 1970 for anything but experimentation..Overseas call were a combination of AT&T to the Trans-ocean cable or to High {4.0 MHz to 18.0 MHz range}Freq AM radio. Once you connected to the other country's technology, you became a victim of their equipment which was not 100% compatible with ours. Plus many of these countries were in the "dark ages" as far as telephone equipment. Fading was probably caused by use of the HF radio connection.
Ok thanks the AM makes since by it's very nature there would be fading issues. The only place I managed to make a call back to the states from a phone booth was in Vience. It went right through.
We could call home via HAM Radio relaying but that was limited and no privacy. My cousin deployed on the USS LINCOLN a few years back and he could call home from on the ship at about any time via satellite. But he paid through the teeth to do it to.