Range with external antennae?

[Xtof@DotDot]

I am using a ESP32-UE chip connected to a WiFi router with a throughput of 50 MB/s. The node has an external SMA antenna (through a U.fl to SMA cable). I am connecting to the node with a smartphone and measure throughputs of the internet connexion. I am reproducibly measuring a throughput (in MB/s) **lower** with a 12 dBi (30 cm) multi-directional antenna (3 MB/s) compared to a 5 dBi (9 cm) multi-directional antenna (8 MB/s), at equal distance/positioning. While I understand why the throughput is lower on the node compared to the router, I do not understand why the throughput is lower with the 12 dBi antenna, and that much lower. Is there any problem of adaptation of the higher gain antenna to the ESP32-UE? Experience / answer anyone?...

[MicroController]

First thought: A 12dBi has a more narrow radiation pattern than a 5dBi, so it requires better "aiming" and is more sensitive to deviations from the ideal orientation between the RX's and the TX's antennas.
Second thought: Not all antennas and rf connections are of the same quality, and cheap ones may often overstate their specifications.
Second thought #2: 30cm (physical size/length?) for a 2.4GHz antenna?!

[Xtof@DotDot]

Thanks a lot for your reply. I was not aware that this antenna could be directional (https://amzn.eu/d/38mbdAj). But OK, I'll try this. According to you, what would be the best way to extend a WiFi from ESP32 to say 500 meters and beeyond? What type of antenna do I need to use? Does the antenna need to be equipped with a powered amplifier?

[corz.org]

What he said.

I'd wager you could get equal throughput if you "aimed" the antenna perfectly. But that's stoopid. Best to use a lower gain antenna which probably has a more suitable gain pattern for your usage scenario (which I'm assuming is indoors).

Find the perfect gain by messing around with multiples of 12.5cm (2.4GHz wavelength-ish) length antenna to get the correct gain for your setup. I mean just bits of wire, until you find the best gain.

[corz.org]

You could hit 500M, unobstructed, with a (good quality) 5dBi omni-directional antenna. No problem.

Higher gain antennas are more "focused". And as energy cannot be created or destroyed, the higher the gain, the farther the reach in one direction, but at the expense of power in all other directions.

You can get 2.4GHz "dish" antennas at 20dBi and beyond, but of course, the focus is greater still. Your choice depends on many factors.