[walrus01]

The part about CSMA reminded me that as an educational model, a lot of what can go right, or wrong with an 802.11(abgn/ac/ax) network is at what we would call layer 2. If you've ever seen an environment that's a CSMA hell of -70 noise floor in 2.4 GHz and devices stomping on each other, or a poorly configured "mesh" network, that's all layer 2. Thinking about things like, how are your design constraints different when dealing with a half duplex/TDD air medium, vs something like a traditional FDD point to point microwave radio?

But then as a mental model in order to understand that, it's important to think about the layer 1 of what the wifi radios are doing: Questions such as, why is this Comcast 802.11ac home router running in an 80 MHz channel, stepping on this other device that's also trying to run in the same 80 MHz channel? Why did somebody install a unifi AP with a torus shaped RF pattern vertically on a wall, instead of horizontally on a ceiling as it was intended?

[bombcar]

I wish more devices came with diagrams showing the RF pattern - I honestly have no idea how I’m supposed to orient the antennae on my Mikrotik.

[zamadatix]

"ceiling mount" in the name always on ceiling, "wall mount" on wall, "directional" in the direction you want, if not specified horizontal on a table (ceiling mount acceptable). If there is going to be a dead zone in the omni pattern it's generally the "back" (where most other stuff is like ports and power). On ceiling mount the back will be able to go straight up into a ceiling, if the back is just one of the smaller sides then it's definitely meant to sit on a table.

[walrus01]

what model do you have? If it's an all-in-one router like a HAP AC, it should be horizontal, best coverage would be if it were flat on a wood shelf or similar.

[bombcar]

It’s one of the ones with adjustable antennae - RB4011iGS+5HacQ2HnD-IN-US - and based on the pictures I have them pointing “up”.

[walrus01]

Aren't Mikrotik part numbers just the most amazing things? For something like that, the antennas are omnis, the RF pattern coming off each one is an oval. Mostly vertical and maybe with the ones at the sides a bit at an angle is a good choice.

Visualize if you were to take a pencil and skewer it lengthwise through an oval shaped fruit, the fattest part of the fruit would be the highest gain part of the antenna's RF pattern.