Very roughly, long wavelengths are better suited to applications that require transmission over large distances. For this reason, applications of infrared waves are currently somewhat limited, but an important one to those who like the easy life is in remote controllers for TV sets. The carrier is a pure sine wave, with some fixed frequency and amplitude. The modulation makes slight changes in some property of the wave, depending on the information to be transmitted. Mathematicians prefer to think about the so-called Fourier decomposition of the radio signal, which indicates how the radio signal is made up of a mixture of different frequencies.
Wide pipes can carry more information than narrow pipes.
A little politics To accommodate many users simultaneously in the spectrum, we would like to give them all their own channel, but there simply are not enough channels to go round. Fortunately, he was pessimistic. Advances in radio equipment have meant that we can now use higher frequencies than in the 1920s, and use them more efficiently. Nevertheless, in the late 1990s, even arch-optimists would concede that the spectrum is now acutely congested. Congestion in the spectrum means it is increasingly difficult to avoid the radio interference caused when two people, geographically nearby, try to use the same channel for different purposes.