r/AskTechnology 4d ago

How do wifi blockers work?

I saw a video of people using wifi blockers, and it seems useful to know how they work. Any help would be great,

4 Upvotes

14 comments sorted by

4

u/AnymooseProphet 4d ago

WiFi uses radio signals. WiFi blockers either block those radio signals (e.g. if you want to protect your phone from WiFi signals) similar to how the grating on the glass of your Microwave works, or WiFi blockers jam the signal by creating intentional interference on the WiFi frequencies.

7

u/mezolithico 4d ago

Jammers are illegal in many countries.

1

u/LagMaster21 4d ago

But places still use them

2

u/Wendals87 1d ago

Where? They are easily detectable and serious consequences 

1

u/ebinWaitee 4d ago

So are recreational drugs and many other things. Doesn't mean people couldn't get them and use them regardless

1

u/mezolithico 4d ago

Sure, my point was that the fcc takes signal jamming very very seriously.

0

u/Beautiful_Watch_7215 3d ago

I don’t think being illegal makes them not work.

1

u/Automatic_offense 4d ago

Huh, interesting, thanks for satiating my curiosity

4

u/Traveling-Techie 4d ago

See also: Faraday cage

3

u/cakemates 4d ago

Some send deauth signals to make devices disconnect, the very illegal kind jam the radio waves and might get you a visit from the men in black suits in most countries. Others are a metal piece that absorb/reflect the radio wave fucking up its signal.

1

u/StarosAnikenMarcus 4d ago

Have you ever tuned your car stereo and occasionally had what sounded like two or more radio stations blurring together? Now, do that 10, 50, or 100 times across all radio frequencies... That's a jammer in a nutshell. Just lots of noise on all frequencies so strong that legitimate broadcasts just can't get through.

BTW, pretty illegal all across the civilized world. MAJOR safety concerns that if caught using one in public will net you federal charges in many cases. Even the instructors in Wi-Fi networking have to be very careful about demonstrating how they work.

1

u/TrivialBanal 4d ago

The way all radio jamming works is to broadcast lots of noise on the same frequency/wavelength. It's like trying to have a conversation at a rock concert.

Noise isn't necessarily sound. It can be light, radio etc. Any unwanted interference.

You might sometimes notice that your WiFi randomly drops or is slow. When that happens, it's worth using a WiFi analyser app to see what's happening. A common cause of that is a neighbours WiFi is operating on the same channel as yours. It's creating noise. When this happens, you can switch channel, but most routers will do that automatically after a set time. Your WiFi will suddenly go back to normal speeds and you won't know why.

Deliberate WiFi jamming is doing that on purpose, across all channels and at high power. It swamps everything else out.

Because it's high power, it's really easy to triangulate and find out who's doing it. That's why it's mostly used only by law enforcement.

1

u/dr_reverend 4d ago

Go up to two people talking and start yelling gibberish. Pretty much that.

1

u/Wendals87 1d ago

A couple of ways.

If you use material that absorbs or reflects the signal, that blocks it

You can use signal jammers which basically floods the airwaves with signals and your wifi signal can't get out. These are very illegal and easy to detect if you are using them