I know that wifi routers are essentially weak microwaves but wouldn’t multiple antennas cause interference or so?
In: Technology
There is several bandwidths that WiFi routers broadcast. They need a separate antennae for each bandwidth.
You CAN use one antennae to pick up several different frequencies. But it’s less than optimal. You REALLY want to optimise your WiFi. WiFi is important as hell, if it worked significantly less well on some devices, it’d piss you off.
Since WiFi has to operate in complicated environments, and the chances of signals reflecting off of surfaces before reaching a device is high, There’s a real probability that for example, some of the signal could take a more direct route, some could take a less direct route, and they could arrive 1/2 a wavelength apart. this would make the signals destructively interfere and produce a signal dead spot (one reflection is positive as the other is negative, so they cancel). To fix this, having two antennae broadcast the same signal at 1/2 a wavelength apart means that the same set of reflections has to happen twice, which brings the probability of a signal ‘dead zone’ down. This is known as signal Diversity.
In more modern routers it can be used for ‘beam forming’ where the router and device can establish a frequency that produces the least destructive (or most constructive) interference, and the router can produce 2 out of phase signals that fit this profile best and cause constructive interference at the device.
Sorry this ELI5 got a bit technical
Think of it like a walkie talkie/hand radio. One antenna = listen OR talk. Not both. Your WiFi box probably has two antennas. One for talking to your devices AND one for listening. It’s the same for any communication radio on trucks, planes, or whatever else.
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