Radio tubes

I've been toying with the idea of transmitting data at a low bandwidth using soundcards and walkie-talkies, but the range of a cheap walkie-talkie is very low, a fraction of a nautical mile in fact. This could presumably be improved by some kind of dish which focuses the signal onto a particular point, possibly several minutes of latitude away, but this would have to be precisely aimed, the focal point would be hard to locate and jogging it slightly would shift it to the houseboat next door or something, plus all the bobbing up and down would make it difficult. So, what if instead of having a dish something like a metal tube or pipe were used between two walkie-talkies? Would this not increase the range of the signal? Obviously i'm talking about on land, not in the water.

Also, if you had two mobiles/cellphones using Bluetooth, could you not then communicate using such a tube over a greater distance, if you only ever texted (et caetera) one person?