@Eccololo 

Hi,

How far is the distance between your gaming PC and the Wi-Fi router?

If the Nano adapter with its tiny antenna can only see the Wi-Fi network, but can't establish a connection and the TL-WN321G with its larger antenna is able to connect, but at a slow speed, then this could be a reception issue.

Would it be possible to move the PC very close to the Wi-Fi router and then do another speedtest?

@woozle thank you for your help.

The wifi range is not the problem because I have installed in my room TP-Link wifi repeater. The signal is good. 

The most probably there is problem with compatibility wifi adapter with Ubuntu system. I am looking for wifi adapter which works in plug and play mode with Ubuntu and works well in meaning with 15-20 Mbps speed like my other devices in my wifi network.

Can you recommend any device?

Thanks 🙂.

  @Eccololo 

Normally, if your PC shows Wi-Fi networks with either the Archer T2U Nano or the TL-WN321G, then it should mean both adapters are functioning.

Is your Wi-Fi network only 2.4 GHz or is it dual band (i.e. 2.4 GHz + 5 GHz)?
 

Hello @woozle. Thank you for your help.

As I discovered my WiFi was 2.4 GHz + 5 GHz. I turned off the 5 GHz signal and now my Wifi is 2.4 GHz.

I would like to share here a screenshot of the speed test results but when I try to do that I can't because of a bug in this community forum. It is says that "Image source is still missing", like it needs a URL when I choose to upload an image. Nevertheless, my speed test results are:

1. Download: 0.84 Mbps

2. Upload: 8.66 Mbps

I would like to ask for further support in solving that problem.

Thanks 👍.

  @Eccololo 

Nice to hear that you found a solution.

By the way, sometimes also the PC itself can be a source of interference. Especially USB 3.x "SuperSpeed" devices are known to affect the 2.4 GHz band.

Have you also tried the Archer T2U Nano again? Provided the Wi-Fi signal is good an Archer T2U Nano should give better speed than a TL-WN321G.

  @woozle I tried all combinations but tplink t2u nano is not working. Till Ubuntu 22.04 it worked. If you find any workable solution then pls let me know.