I have recently bought hAP Lite RB941-2n. My intention is to use it for extending WIFI network range between 2 buildings.
it is rather far from "main" router and the signal is very weak.

I have a feeling that external antenna would help. I had a TP-LINK TL-MR3420 router in the very same place. It worked very nice, signal was much better. I have 2 cameras connected to this router and with TP link I had good enough signal to watch 2 full HD streams.

I saw some DYI video of adding external antenna to increase the wifi signal strength. see https://www.youtube.com/watch?v=Rxe1g74t0BE
Has anyone here done it? Could that help?

I understand that I might have bought the wrong device for this task. Please recommend what I should have bought instead.

I have done small research on other devices provided by Mikrotik and seems to me that SXTsq Lite2 could help in my case. https://mikrotik.com/product/sxtsq_lite ... ifications

I am asking somebody who understands this topic to confirm that my assumption is correct!

The setup would be:
Main building:

• Main router RB951Ui-2HnD providing WIFI access point

Second building:

• SXTsq Lite2 device that is connected to main Wifi

• hAP Lite RB941-2n device connected tu SXTsq by enthernet cable

• Camera devices connected to hAP Lite RB941-2n LAN ports

This device doesn't support any kind of external antenna, despite what random youtube video tells you.
Your setup looks good. What is the exact problem that you are facing with it? Signal is weak for devicez using the hAP Lite? How far are they, and what kind of devices are they?

Thank You! noted regarding external antenna.

Current setup is
Main building:

• Main router RB951Ui-2HnD providing WIFI access point

Second building:

• hAP Lite RB941-2n device. Cameras connected to this

Distance between buildings is approximately 50 meters.
Problem that I have is that wifi signal is barely enough for the two routers to connect. and absolutely not enough for video stream.

Previously I had TP-link router with external antenna in Building 2. The signal was good enough for video stream. Thus my first idea was to add external antenna to hAP Lite, and my second idea is to use SXTsq Lite2 as the device that connects to the wifi.
Before I purchase the device I would like to have some confidence that it will help in my situation. thus I write this.

@normis, please confirm that given my situation a SXTsq Lite2 device will help!
Thank You!

It is hard to say, but most likely yes. Is the main AP router visible from the location you will put SXT Lite2? Since that is an indoor device with a small antenna, no matter what you point at it, it will partially depend on the AP. Communication is bi-directional after all.

Thank You for comment!
they main AP router is "almost visible". There is wooden wall in between.
It was working with the same main AP router + TP-Link device on other end thus I believe that the signal from main AP is strong enough.
I will give it a try with SXT Lite 2. Thank You!

Works perfectly. Thank You for helping!