RTL8812BU adapter less sensitive on Ubuntu

[alimas7]

Hello,

First: a big THANK YOU! to @morrownr for this repo and the efforts put into it.

Am not sure if there is an issue but am posting this here in case there are suggestions for my scenario.

Have been using an RTL8812BU (0bda:b812) external adapter with dual 5 dBi antennas on Windows 10 for a while.

WiFi router is in the house and the laptop in the garage on other side of lawn. The router and the RTL8812BU adapter are already on the edges of the house and garage, respectively, i.e., as close as possible. Other than the house and garage walls that face each other, there is nothing else in the line of sight between the router and the RTL8812BU adapter.

Am switching from Windows to Ubuntu 21.04, starting out with Ubuntu running as a guest VM on the Windows host.

The steps outlined through https://github.com/morrownr/88x2bu#installation-steps are easy enough. I did not encounter any problem building and installing the Linux driver (dkms status outputs rtl88x2bu, 5.8.7.4, 5.11.0-37-generic, x86_64: installed).

The below is based on the same stationary location of the laptop in the garage.

With the Windows driver, the RTL8812BU adapter is able to get a stable + useful signal from the router, not the strongest but quite sufficient for my needs in the garage.

With the Linux driver, the same RTL8812BU adapter attached to the Ubuntu VM seems to be operating weaker: the router's SSID would appear and disappear that the adapter has not been able to successfully connect.

Before considering a different WiFi adapter, I'm trying to get information on the following.

a. Are there configurations that I can try to tweak for the Linux driver to allow the RTL8812BU adapter to receive a stronger signal from the router to be able to connect to it?

b. If there are diagnostic steps I can try out in Ubuntu, I'd appreciate pointers on that, too, as I'm not yet familiar with the Linux wireless networking.

Thank you in advance for any help.

[morrownr]

Hi.

I have no experience running a usb wifi adapter in a VM so I have a blind spot there...for now.

Three things come to mind:

1. Go into the driver directory and run:

$ sudo ./edit-options.sh

Change rtw_beamform_cap=0 to rtw_beamform_cap=10 and reboot.

2. Check your txpower:

$ iw dev

We may need to see about bumping your power up a little if the adapter allows it.

3. There is a section of the README called...

Recommended WiFi Router/ Access Point Settings

Take a look and let's discuss it.

Bonus: If you feel like looking at an adapter that is known for long range, take a look at the ALFA AWUS036ACHM. You can find links to it and other adapters at the following repo:

https://github.com/morrownr/USB-WiFi

And there is another bonus in that this ALFA adapter uses an in-kernel driver so no compiling.

Regards

[alimas7]

Hello @morrownr,

Thank you very much for your reply and the details.

I have no experience running a usb wifi adapter in a VM so I have a blind spot there...for now.

The WiFi adapter is connected as a pass-through to the VM. I believe there's no or very small difference in terms of performance from the VM's standpoint.

Change rtw_beamform_cap=0 to rtw_beamform_cap=10 and reboot.

I tried changing that configuration and it didn't seem to make any difference after rebooting. I also tried the other possible values and also did not see any difference in the receiver (the WiFi adapter) detecting a stronger signal.

Recommended WiFi Router/ Access Point Settings

Through trial and error attempts, the router had been set to the maximum allowable/legal power a year ago and had also been placed optimally and configured to use the least busy channel. This past weekend, I tried repositioning the router and rechecked to confirm channel 36 is still the least busy. Tried different combinations and even made the situation worse (SSID didn't show up at all).

Bonus: If you feel like looking at an adapter that is known for long range, take a look at the ALFA AWUS036ACHM.

I'm considering whether to invest in that ALFA WiFi adapter or if using a stronger antenna (maybe even a directional one) on the existing adapter would work better. If you've had experience in comparing such, I'd appreciate it if you could share that experience+observations.

Also, have you had experience with ALFA AWUS036ACH (without the "M") that seems to use the RTL8812AU chipset?

Besides the in-kernel driver, is the radio MT7610U in the AWUS036ACHM superior to the RTL8812AU in terms of signal strength?

Thank you again and have a great week!

[morrownr]

I'm considering whether to invest in that ALFA WiFi adapter or if using a stronger antenna (maybe even a directional one) on the existing adapter would work better. If you've had experience in comparing such, I'd appreciate it if you could share that experience+observations.

I'll be glad to share. I have considerable experience with USB WiFi adapters.

Also, have you had experience with ALFA AWUS036ACH

Yes, i have one.

. (without the "M") that seems to use the RTL8812AU chipset?

That is correct. The ACH uses the rtl8812au chipset.

Besides the in-kernel driver, is the radio MT7610U in the AWUS036ACHM superior to the RTL8812AU in terms of signal strength?

I can do better than a simple yes. Go to:

https://github.com/morrownr/USB-WiFi

...and read the file called Performance_Comparison.md

The ACHM and ACH both have high quality, very sensitive antennas as well as good internal amps. These two adapters have the longest range of any modern dual band adapters that I have used and tested.

I am curious what kind of numbers you are seeing;

$ sudo apt install wavemon

$ wavemon