[baq]

if my router has 3 antennas, is there any point to installing it only on one of them? my intuition that's based on exactly no RF experience whatsoever tells me that it'll do more harm than good. (case is weak 5GHz signal in the corner of a house.)

[geforce]

Depends. Some routers have multiple antennas because there are multiple transceivers inside it, and some technologies (i.e. MU-MIMO in 802.11AC) will most likely react strangely having one of their antenna modified. In the end, it would probably make your performance even worse.

[bsamuels]

theres a two reasons your router probably has 3 antennas:

-beamforming

-split 2.4ghz/5ghz/5ghz-wave2 antennas

if your router is using those three antennas for beamforming, you might trigger some strange behavior if you yagi a single one of them. if run into issues and can turn beamforming off, you should be able to yagi a single one no problem.

if your router pumps each antenna into a separate radio, then you can reliably pump a single radio into that corner of your house w/ a yagi. however, you won't have seamless roaming between the 2.4ghz and 5ghz networks when you move into and out of that corner of your home.

i recommend getting a mesh network, they're the bees knees and are a huge step above the traditional access point + range extenders model