What is a wireless bridge, and how does one work?

A wireless bridge is a pair of radios that link two locations over the air, behaving like an ethernet cable buried between them. One sits at the building that has the internet connection. The other sits at the building that needs it. They are aimed at each other and they carry traffic between the two.

Everything at the far end — cameras, access points, computers, a till — then works as though it were wired back to the main building. That is the whole idea.

Each radio is a directional antenna with a transmitter behind it. Because the signal is focused into a narrow beam rather than sprayed in all directions like household WiFi, it carries much further and is far less affected by interference from other networks.

Both ends are powered over the same ethernet cable that carries the data, so each radio needs one cable back to a small injector indoors, not a power outlet up a mast.

Aiming is the part that decides whether it works well or barely. A link that is roughly pointed will connect and look fine on a good day; a properly aimed one holds full throughput in weather.

A WiFi extender repeats an existing network in all directions, halving throughput each time, and needs a decent signal where it sits. It is designed to fill in a dead corner of a house.

A bridge is point-to-point and directional. It is designed to cross open ground. Using an extender for a job that needs a bridge is the single most common mistake we get called out to fix, and it is why so many properties have a shop with four bars of signal and no usable connection.

Line of sight, almost always. The two ends need to see each other. Buildings, terrain and — most commonly around here — trees are what get in the way.

Trees deserve particular attention because the problem is seasonal. A link aimed through bare branches in February can degrade badly once the canopy fills in. Any survey worth having assesses for June, not for the day the installer happened to be standing there.