conducting a wireless network site survey
You can throw the ball down once, but if you bounce off a wall, you can see the ball bouncing back and forth between the two parties since the transverse corridor. Radio waves do that too, only more like this: A part of the wave goes straight down the hall, but each edge of the wave bounces between the walls. The part of the wave is moving directly towards the corridor when the first antenna and the signals will bounce milliseconds later. The network card is smart enough to know that while you receive the same transfer again, only one copy of the transfer used.
As a column casts a shadow on the path of a flashlight beam, the obstacles in the way of an RF wireless transmission of generated shadows. If you have an antenna mounted on the access point a column of the building, the air in the rear of the column in the shadow of the RF.
