In October of 1945, an article titled "Extra-Terrestrial Relays — Can Rocket Stations Give Worldwide Radio Coverage?" was published in Wireless World magazine, in which world-renowned science fiction author Arthur C. Clarke discussed the idea that, in the near future, artificial satellites placed in a geostationary orbit (now sometimes known as a "Clarke Orbit") could be used as repeaters to relay radio signals.
Eleven years later, Clarke wrote the following letter to Andrew G. Haley. In it, he mentions the aforementioned article and then expands on his earlier writings by correctly predicting the future development of both satellite television and GPS.
(Source: Res Communis; Image: Arthur C. Clarke on the set of 2001, via.)
Odd that we should have crossed in the post!
I am afraid that I am too much out of touch with current communication theory and technique to provide much of value for you. (In any event, all my war-time experience was in radar, not radio.)
As you may know, my main interest in this subject is in the use of satellite relays, which I think may revolutionise the pattern of world communications. To the best of my knowledge, I was the first to suggest this possibility (see "Extraterrestrial Relays", Wireless World, October 45). By another odd coincidence I've just sent my agent an article on these lines, entitled "The Billion Dollar Moon", giving my latest view on this subject. My general conclusions are that perhaps in 30 years the orbital relay system may take over all the functions of existing surface networks and provide others quite impossible today. For example, the three stations in the 24-hour orbit could provide not only an interference and censorship-free global TV service for the same power as a single modern transmitter, but could also make possible a position-finding grid whereby anyone on earth could locate himself by means of a couple of dials on an instrument about the size of a watch. (A development of Decca and transistorisation.) It might even make possible world-wide person-to-person radio with automatic dialling. Thus no-one on the planet need ever get lost or become out of touch with the community, unless he wanted to be. I'm still thinking about the social consequences of this!
But as for details of frequencies and powers, I'll have to leave that to the experts to work out; I'll get on with my science fiction and wait to say "I told you so!"
Arthur C Clarke
P.S. Any chance of seeing you in London? I leave for N.Y. on 28 August.