Hey everyone, thanks for coming back to Wi Fi fundamentals with location and analytics. This course will help you to muster the air. We are starting arranging and location part. To understand it properly. We must first learn of signal propagation. The way our signal travels from one side to the other, how signal propagate in space?

How do they lose their power? How much power is lost in their path? signal propagation is a science of itself. We will touch on the basics that will lead us to a good foundation when we deal with Wi Fi signal. Our waves propagation are affected by many things, our atmosphere, different layers of the atmosphere the troposphere the area that flies from the Earth's ground up to about eight kilometres, and the ionosphere, the layer above that actually reflects our waves and make them turn back to Earth. Our Sun state, time of day temperature and air steering.

The first type of propagation is ground wave propagation. This signals are below two megahertz and they will follow the curvature of the earth. They're used by long wave radio stations to reach almost any spot. The second type are skywave this signals are between two and 30 megahertz the waves actually bounces between the ionosphere and The Earth, they're being reflected and they are affected by many reasons including the state of the sun. The third type are signals that relies on the line of sight. These are the signals above 30 megahertz.

In order to receive them, we need the path to be without obstacles. Wi Fi networks use line of sight propagation. Signal propagation is a great theory but in real deployments, we will see that Wi Fi signals tend to attenuate very fast they will be absorbed by different obstacles. Some of the signals will reach the receiver weaker, some will not. And the real question is how much is the received signal compared to the transmitted signal? How a signal attenuates over a distance?

And this is the topic of our next video. How much power do we lose?