A torch and a lamp
A lamp in the middle of a room lights every corner a little. A torch lights one spot a long way off.
Wi-Fi antennas work in the same two ways. Some spread the signal all around. Some point it in one direction.
Which one you pick decides who gets a signal, and how far it goes.
Key words
| Word | What it means |
|---|---|
| Antenna | a part that sends and receives radio waves |
| Omni-directional | sending the signal equally in all directions around it |
| Directional | sending the signal mostly in one direction |
| Gain | how much an antenna focuses its signal in one direction |
| Dipole | the simplest antenna: two short rods, often the one on a router |
| Patch | a flat, square antenna that points one way, often fixed to a wall |
| Yagi | a long antenna with rods in a row, like a roof TV aerial, with a narrow beam |
| Network | computers and devices joined together so they can share data |
| Router | a device that joins one network to another |
| Access point | a device that gives Wi-Fi to a wired network |
| Point-to-point link | a radio link between two fixed places, such as two buildings |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can describe five kinds of antenna and choose the right one for a job.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Omni-directional and dipole
An omni-directional antenna sends the signal in all directions around it, like a lamp. It covers a whole room or floor. But the signal is spread thin, so the range is short.
A dipole is the simplest antenna: two short rods. It is the "stick" you see on a router. Its pattern is omni-directional, shaped like a ring around the rod.
Directional, patch and yagi
A directional antenna focuses the signal one way, like a torch. It reaches much further in that direction, and almost nothing is sent behind it. This focus is called gain.
A patch antenna is flat. It is fixed to a wall and sends a wide beam into a room or a corridor.
A yagi has rods in a row. Its beam is narrow and goes very far. It suits a point-to-point link between two buildings.
Quick check
Have a go
Quick check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.