How Radio REALLY Works
©2005 William Beaty

Radio signals are a lot like sound; a kind of sound which we cannot hear. High pitched sound or "ultrasound" is not audible to humans. Imagine for a moment that Radio is a kind of sound wave.

With ultrasonic sound, we could be surrounded by those sound waves right now and not know it. The sounds could be really loud, but our ears don't detect anything. And perhaps there are naturally occuring sources of these inaudible sounds. Perhaps certain animals could hear this type of high-pitched sound, while for centuries humans might remain unaware of an entire complicated sound environment made of inaudible sound. We's finally discover its existence when special microphones were built which could pick up the high pitch signals. Scientists and engineers would soon learn how to transmit powerful but inaudible sound, how to reflect it and focus it, how to use it as a tool. It's just sound... but because it's inaudible, we can use it for all sorts of things where normal sound would cause problems.

And just think: what if we built some really powerful loudspeakers which could broadcast ultrasonic music for hundreds of miles? And what if we made some little electronic receivers which would turn the inaudible sound back into normal music? That would be cool. Someone could sell a lot of them. Can't do that with normal sound. You couldn't put a hundred thousand watt loudspeaker anywhere near a city. But if the loudspeakers were not audible, then we could put lots of them right in populated areas. But people might not want to live right next to a hundred kilowatt ultrasound broadcaster. We can't hear the sound, but REALLY LOUD sound can do weird things.

Radio... is not sound. But do you see all the similarities? We usually think of radio as something really weird, something inexplicable without complicated math and physics. But when you get right down to it, radio is very much like high-pitched sound; like music and voices that we can't hear.

OK, so how is radio DIFFERENT from high-pitched sound?

1. Sound in air is reflected by solid walls, while radio is only reflected by metal walls (and other electrical conductors such as wet dirt.)
This means that a big "radio loudspeaker" can send inaudible music right into closed rooms hundreds of miles away. Ultrasonic music would be blocked by the walls. So I guess my wonderful idea about megawatt sound transmitters wouldn't work, because the special microphones would have to be up on the roof outside your house. (Hey, wait a minute!)

The radio "sounds" will go through almost any substance except metal.

2. Sound-music is made of waves moving through physically vibrating materials, while radio-music is made of vibrations in the magnetic fields present in empty space (and also vibrations of the electrostatic fields of space.)
Radio can travel through empty space. Can't bounce sound waves off the Moon. But we
3. Ultrasonic music can travel through narrow tubes... but much of it is lost as it travels. We can send radio-music along wires with almost no losses.
Ultrasound can only travel a short distance through a narrow pipe. Even worse, it's hard to put junctions on the pipes, and hard to control how the acoustic energy splits at the junctions. And if a pipe got crushed, even crushed a little bit, it would reflect the ultrasound backwards down the pipe. This means that a technology based on "ultrasonic hollow pipes" would be a big problem. But radio music can travel along pairs of thin metal rods thousands of feet long. The rods can be bent and crushed with little effect on the signals. Junctions are easy to make; you just touch the metal parts together. And the radio energy follows simple rules when it splits at a junction. We could create an entire technology based on "radio music" traveling along very thin curvy metal rods.
    by metals.

lots of ultrasonic channels

resonant chambers

microphones must transmit in order to receive