I don't understand why it would be difficult to retransmit on the same frequency... I might be missing a very huge piece of this, but if I simply have an antenna, then I filter out all frequencies that aren't in my range, then I amplify those signals, won't I have the exact same signal I started with, only amplified? And couldn't I just as easily put an antenna on the end of this that will simply transmit that signal again?
Are you thinking that I'm going to have to take the signal, demodulate it or whatever, and then remodulate it on another antenna? Maybe you are, and if so, I would definitely have a problem...