In classic MP Prime base get's knocked out by a bio followed by a nuke. The Base computer was programmed to randomly send out wake up codes. This brings up a lot of issues.
Firstly the bad guys know where they popped the nuke. Any radio signals originating from that location would likely have triggered some sort of investigation. The PB crew would have known this was a risk. How would they have dealt with it? One way is to only bounce signals off the Moon
https://en.wikipedia.org/wiki/Earth%..._communication
Now this means they would have needed a directional antenna.