# How Wi\-Fi and Bluetooth Work

See the invisible radio conversations on a home desk: how Wi\-Fi links a laptop to the router and the internet, how Bluetooth links a phone to earbuds, and how both share the 2\.4 GHz band\.

By PETE\!

Topic: Computing, AI & Electronics

[Open the interactive Jig](https://ask.jig.com/j/uMlRbbxEGJIk)

## Transcript

### 1. Invisible conversations

This desk is full of radio\. The router talks to the laptop over Wi\-Fi, and the phone talks to the earbuds over Bluetooth\. Both send data as radio waves you cannot see, so here they are drawn as glowing ripples\. Tap any device to make it call out\.

Drag the room to look around; scroll or pinch to move closer\.

### 2. Radio waves

A radio wave is a ripple of electric and magnetic fields that travels at the speed of light\. Wi\-Fi and Bluetooth both use waves that wiggle about 2\.4 billion times a second, so one crest is about 12\.5 centimetres from the next\. Wi\-Fi can also use 5 GHz: shorter waves that carry more data but fade sooner through walls\.

Look for the small print on the router front\.

### 3. Bits ride the wave

A steady wave carries no message\. To send ones and zeros, the radio changes the wave many times a second\. Wi\-Fi changes its height and its timing together, packing many bits into each change\. Bluetooth simply nudges its frequency a little up or down for each bit\.

Wi\-Fi 6 can pack 10 bits into one change, using a pattern called 1024\-QAM\.

### 4. Wi\-Fi: through the router

Wi\-Fi is the wireless hop between your device and the router, not the internet itself\. Before sending, the laptop listens to check that no one else is talking\. Then its message flies to the router, which passes it down the cable to the internet, and the answer comes back the same way\.

Every Wi\-Fi message is acknowledged\. If no ACK arrives, it is sent again\.

### 5. Bluetooth: a personal link

Bluetooth links two nearby devices directly, with no router\. New earbuds advertise on three special channels: here I am\. The phone answers, they pair and agree on a shared plan, and then music streams in short, regular bursts that let the earbuds sleep between them to save battery\.

Typical reach is about 10 metres; the strongest radios manage around 100 metres\.

### 6. Hopping between channels

Both radios share the same crowded 2\.4 GHz band\. This router uses Wi\-Fi channel 6, a wide 22 MHz slice\. Bluetooth splits the band into 79 narrow channels and hops to a new one 1,600 times a second, slowed right down here\. With adaptive hopping it learns to skip the busy Wi\-Fi channel\.

Both ends know the hop pattern in advance, so the hopping is not random chaos\.

### 7. Two radios, one phone

Wi\-Fi is built for speed: wide channels and a router that connects you to the internet\. Bluetooth is built for low power: narrow hopping channels between your own devices\. Your phone uses both at once, streaming a song from the internet over Wi\-Fi and on to your ears over Bluetooth\.

A microwave oven works near 2\.45 GHz too, which is why it can disturb 2\.4 GHz Wi\-Fi\.