wireless communication. How does the signal know where to go? How is data transmitted through air?
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to answer the second part of your question, data is transmitted in binary, which is sort of a fancy morse code, so it is just like using a flashlight to send a coded message in the dark. the light being used is just in a wavelength that our eyes don’t see.
Radio and light are both electromagnetic radiation. There are some differences due to the different wavelengths but for a lot of things they are very similar.
How does light know where to go? It doesn’t, it goes in all directions. Or if you put a lens/reflector around the bulb you can make a small patch of light.
The radio equivalent is the antenna, some are designed to send Radio signals equally in all directions, some to send a narrow beam in only one direction.
How is data transmitted? By varying the radio signal. The most basic system would be the equivalent of turning a light on and off, the radio version of signal lights on ships.
This turns out to be a very inefficient way to send data. It’s better to use AM modulation (varying the brightness), FM modulation (varying the colour) or a number of other more complicated methods that don’t have easy to explain equivalents.
How do lots of radio signals travel at the same time? This is done in a number of ways. By taking turns and by each transmitter using a different colour light are two common and easy to understand methods. There are again other more complex methods that are also used.
Just like with sound, wireless (or radio) goes in all directions (like a donut). Radio waves are essentially light, but way below what is visible to us.
Note that it is possible to focus or direct radio waves. This was done with the “rake” antennae for old school television, dishes for satellite, and MIMO in WiFi.
Wireless communication almost always uses electromagnetic waves or other electromagnetic phenomena like magnetic fields. Sound is an alternative but quite impractical for most applications.
Light is an electromagnetic wave too. If you look at it for communication the main difference is that lots of material that is not transparent to visible light is transparent to radio waves.
The transition of information is like if you do it by blinking with a lamp. Use morse code with a blinking lamp and you have wireless communication. Signal lamps are used that way on military ships for communication.
You can have a lamp that emits light in all directions equally. You can also have a lamp with a reflector that only emits light in one direction. the light does not know where to go, to direct it you need to do it at the sender.
Radio signal do not know where to go just like light, but the device that send them can do that in a specific direction.
The same way light knows where to go when you turn on a light bulb. It doesn’t first scan the room and go “there’s a guy reading over there, we’d better send some light his way”. It just goes all over the place, lighting the entire room. It’s not really directed at all.
In some cases you may have directional antennae, but that just works something like a flashlight: light is sent in *that* general direction, but again, not guided towards any *specific* object or receiver.
The signal isn’t directed to a specific end user device. It’s broadcasted out in a dome around the Access Point (AP), the client device then receives the radio waves, then sends out its own it the same dome shape for the AP to receive.
WiFi is transmitted on either the 2.4 GHz or 5 GHz radio wave frequency.
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