What causes internet speed drop in linux?

Question

linux

MX Linux system on an HP 430 laptop. The
Internet via wi-fi consistently gave out 30-40 Mbps, but at some point the speed drops sharply and does not rise above 1-3 Mbps, at a constant rate i.e. reboots don't help. I boot from a live disk (it doesn't matter, the same MX Linux, Ubuntu, Kali ...) and everywhere the speed is 30-40 Mbps, while the laptop is in the same place, in the same position. A nearby phone on the same network gives out 30-40 Mbps. Those. the problem is soft in the system, maybe I installed something, after which this problem appeared. On the same laptop there was exactly the same problem, but in ubuntu.
Tell me in which direction to dig, I tried to reset the wi-fi settings, connect to another network - the effect is zero, i.e. something in the system does not allow wi-fi to work normally.

Answer 1

The problem seems to have been solved by specifying the antenna socket for the wi-fi module:

echo "options rtl8723be ant_sel=2" | sudo tee -a /etc/modprobe.d/rtl8723be.conf

A more detailed solution is described here: https://www.linuxmint.com.ru/viewtopic.php?t=3335

Answer 2

The problem is not with Linux.
Connect to another network, or change your settings.

Answer 3

kill the neighbors))) so that the channel is not occupied
PS
choose some one fixed one (look at the wifi statistics, decide which one is better / not busy
PS
as an option = the router died