Heh, the all-mighty Alpha 1!!! So, let's say we did have radio transmissions from Earth... What circumstances do you think they'd keep that from the rest of the GTVA, including military personnel? Sol system was the terran's anchor, so you would think that they'd release to everyone that they've been in contact with Earth/Sol system just to keep morale and hopes up... Unless something so bad had gone down in Sol to keep it from everyone else.
What do you guys think was so bad that they'd keep it from everyone? Civil unrest? At least with Earth, we've survived thousands of years on our own and don't think we'd crumble so quickly; we're pretty adaptive. Maybe other colonies getting stupid and attacking Earth? Possible... Do we know how many colonies there were in the Sol system besides Earth?
I can imagine that during the decades away from Sol that a lot of terran citizens of the GTVA would protest, complain massively and noticably, and generally be restless about getting contact to Earth. And I think people in that age would know it would only take a few years (maybe less if technology was that advanced) for a radio transmission to reach Sol. It would certainly be interesting to see a campaign about those times of Sol's uncertainty...
I'm sure they probably did contact Sol during those years, or at least lied to the populations that they did (just to calm them). I think it was one of those historical things that V didn't put into the game either because they didn't have time (like the developers of Mechwarrior 2, where they had this history database that was never finished because they ran out of time) or because they didn't think it was relevant to the actual game.