What is this thing?

This is an access point, can also have a router integrated.

The many antennas serve to be able to use several WLAN networks at the same time instead of being alternately the case with “normal” routers.

WLAN has two frequency ranges, the old “slow” 2.4GHz and the new “fast” 5GHz. For this, you need twice as many antennas as an antenna has to match the frequency. It is possible to assemble the antennas into a “strip”, but they interfere with each other when they have to send at the same time.

Next is Beam Forming. By means of two antennas, one can concentrate the transmission power in a certain way with a trick instead of radiating the entire energy in all directions. This works like a lighthouse that can make the light visible as a beam with a weak light bulb (for example 70 Watt). Here, the transmitter turns the so-called “coil” (bundled radio waves) in the direction of WLAN device so that you get more reach here.

This makes 4 antennas, which is standard for expensive accesspoints and routers.

And then you can have the whole thing twice again to supply data-hungry devices such as streaming TV or PC with “Great Download” separately from the rest to achieve as complete data transmission as possible.

You’ll be at 8 antennas. Unfortunately, however, there are many “fake” devices that then simply have empty plastic as fake antennas which look like the expensive ones with the above-described functions.