Why does FM sound better than AM?

Someone gave me an analogy some time ago that made a lot of sense.

If you shine a flashlight through a tree blowing in the wind and vary the brightness to convey information, the signal can get distorted pretty easily.

However, if you have a constant brightness source and vary the color, it’s a lot easier to figure out what the source is trying to convey.

I always shy away from analogies because more often than not they give the wrong "feel" for a concept. But this is one of those rare exceptions.

It's not an analogy. This is precisely how it works.

Unless your car radio consists of a flashlight and a tree, this is an analogy.

The flashlight is the radio tower, the tree is the tree, and the radio in the car is your eyes. There is no analogy here, it is literally the same EM waves shifted up to where our eyes can see them.

It's like saying that the violins is merely an analogy for how a double base works.

> it is literally the same EM waves shifted up to where our eyes can see them

Rubber ducks aren't battleships because they both float. Visible light and radio attenutate in meaningfully-different ways. It's an analogy.

> Visible light and radio attenutate in meaningfully different ways. It's an analogy.

Lol news to me and my physics degree, Do tell because as far as I'm aware Maxwell's equations don't have an asterisk on them that say "doesn't work below 1 GHz".

> Do tell because as far as I'm aware Maxwell's equations don't have an asterisk on them that say "doesn't work below 1 GHz".

Did you really just pull out Maxwell's equations?

EM interacts with matter in different ways. Glass hardly attenuates visible light, but wood does. 2.4 Ghz can pass through walls better than 5Ghz.

There's the concept of permittivity wherein Maxwell's equations are defined in free space with vacuum permittivity.

https://en.wikipedia.org/wiki/Vacuum_permittivity#Permittivi...

To accurately model EM waves, you need more than just Maxwell's equations. You require material equations to model interactions of EM with media.

If you want to get really advanced, whereas Maxwell's equations are classical physics, there's Quantum electrodynamics (QED) which can model interactions of EM and matter.

https://en.wikipedia.org/wiki/Quantum_electrodynamics

> There's the concept of permittivity

> You require material equations to model interactions of EM with media

> Quantum electrodynamics (QED) which can model interactions of EM and matter.

It's amazing how condescending some people on here are; how could you possibly have missed literally in the first sentence of my response

> ... my physics degree