Peter Cochrane has a simple and very useful explanation of Claude Shannon’s mathematical law of communication, complete with diagrams. And a warning that, when it comes to technology, magic won’t work there, either.

We might thus imagine the energy of a signal dispersed inside such a solid form in the same way that water is retained by the skin of a balloon. We can change the shape of the balloon but the amount of water stays the same. Similarly, different coding and modulation schemes can alter the ratios of the sides presented by Shannon’s equation.

We can certainly trade off signal power against noise and/or bandwidth and time, but we can never exceed the bounds set by nature.