I have install ubuntu 18.04 along side of Windows. I can see that there wifi issue, it does not catch the wifi signal from distance where windows catches the signal from same distance.

I have tried lot of way to figure this out, but unable to find fix for this.

Checked with this below fix but no luck:

Rtl8723be WiFi incredibly weak

The below solution work for ubuntu 14.04 for same laptop.

sudo add-apt-repository ppa:hanipouspilot/rtlwifi

sudo apt-get update

sudo apt-get install rtlwifi-new-dkms

But it giving below error in update command for ubuntu 18.04:

Get:16 http://in.archive.ubuntu.com/ubuntu bionic-backports/universe amd64 DEP-11 Metadata [5,100 B]

Reading package lists... Done                                             

E: The repository 'http://ppa.launchpad.net/hanipouspilot/rtlwifi/ubuntu bionic Release' does not have a Release file.

N: Updating from such a repository can't be done securely, and is therefore disabled by default.

N: See apt-secure(8) manpage for repository creation and user configuration details.

Output of lspci -knn | grep Net -A3

13:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723]

    Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:81c1]

    Kernel driver in use: rtl8723be

    Kernel modules: rtl8723be

Output of grep rtl8723be /etc/modprobe.d/*

/etc/modprobe.d/50-rtl8723be.conf:options rtl8723be ant_sel=2

/etc/modprobe.d/rtl8723-ant-sel.conf:options rtl8723be ant_sel=1

/etc/modprobe.d/rtl8723be.conf:options rtl8723be ant_sel=2

/etc/modprobe.d/rtl8723be.con:options rtl8723be ant_sel=2

Kernel version: 4.15.0-29-generic

Its a problem with the drivers of Realtek RTL8723BE controller.
Do this:

1) Get the new wifi drivers from github:

git clone https://github.com/lwfinger/rtlwifi_new/

2) Go into the directory:

cd rtlwifi_new

3) Build it:

make

4) Install:

sudo make install

Now, the new drivers are installed. To see what is the correct antenna configuration for your laptop, do this:

5) Unload the existing module:

sudo modprobe -r rtl8723be

6) Load the new module with antenna configuration:

sudo modprobe rtl8723be ant_sel=1

7) Now, check the wifi signals using:

iwlist scan | egrep -i 'ssid|quality'

Next, repeat the steps(5-7) with ant_sel=2 in step 6.

8) Whichever configuration gives the better signal quality, make it default by using:

echo "options rtl8723be ant_sel=N" | sudo tee /etc/modprobe.d/rtl8723be.conf

---> Replace N with 1 or 2.

Note: After each kernel update, you need to rebuild the modules.

Yes. this problem is because of the default Ubuntu WiFi driver that gives a weak WiFi signal experience. Also I'm using HP laptop where Ubuntu 18.4.1 was installed. So, here is the easiest procedure works for me.

This script is tested successfully on Ubuntu 16.04.3 LTS

Initially you will require a internet connection. So, You can sit near to your router or connect with LAN network.

Steps:

1. Go to download path https://github.com/navilg/rtl8723be and extract the zip file




2. After extraction we will see a folder rtl8723be-script folder




3. Go inside that folder and you will find install.sh file. We will use this script to run the programs



4. 
   

   Make sure you have installed following programs in your system.
   Programs:

   
   
   
   
   
   • unzip : You can install it using 'sudo apt install unzip'
   
   
   • make : You can install it using 'sudo apt install make'
   
   
   • gcc : You can install it using 'sudo apt install gcc'
   
   
   • wget : You can install it using 'sudo apt install wget'
   
   
   
   


5. 
   

   Now we will run the sript in terminal.

   
   
   

   bash '/home/navi/Downloads/rtl8723be-script/install.sh'
   
   

   
   



6. It will ask for password so that it can install the programs as SuperUser




7. It will check for required programs. If all programs mentioned above exist in your system then it will proceed with installation procedure or else it will ask to install those programs. Those programs are by default installed in Ubuntu 16.04.3.




8. It will ask for permission to download required files. After typing y file will be downloaded




9. Now you need to provide interface name of your wifi.

You can check that using iwconfig command. For that open new terminal

10. Copy paste the interface name




11. Installation is in progress it may take some time. Be patient. Nothing will show on terminal except dot at the time of installation.



12. 
    

    If installation fails,

    
    
    

    Don't worry. It will try installing another file to resolve the issue

    
    
    

    Press y and enter

    
    
    

    Again it will download another file

    
    
    

    Again provide interface name

    
    
    

    It will try installing and may take few minutes based on your system speed.

    
    



13. you can check the background installation processes in log file displayed on the screen



14. 
    

    Now it will ask if you want to delete downloaded files. If you delete downloaded files. You will need internet connection again if in future you will need to install it again. If you retain it you don't require internet connection again and installation will be faster.

    
    
    

    You can retain it or delete it based on your choice. I want to delete it as I already have those file

    
    



15. Installation successful. You can reboot the system for better performance.




16. Installation is successful. After rebooting you will find strong wifi signal.

Please let me know your feedback, suggestions or any bugs on navilg0409@gmail.com

Video guide of this procedure at youtube.

You did wrong things with running the command. You have duplicate entries.

Run in a terminal

cd /etc/modprobe.d

sudo rm 50-rtl8723be.conf rtl8723-ant-sel.conf rtl8723be.conf rtl8723be.con

Now you are clean and you can run

sudo tee /etc/modprobe.d/rtl8723be.conf <<< "options rtl8723be ant_sel=1"

Reboot now and test.

HP Notebooks with Realtek 8723be PCI WiFi will have low signal problems in Ubuntu 18.04 if run with the default drivers.

Download this driver from the GitHub master branch - there's a zip file at this download link.

After download, extract the .zip file to your Desktop directory.

The following method of driver installation corrects the signal problem.

Open a terminal window with CTRL+ALT+T) and execute the following commands:

cd Desktop

cd rtlwifi_new-master

make

sudo make install

sudo modprobe -rv rtl8723be

sudo modprobe -v rtl8723be ant_sel=2

Now check signal strength and...

sudo ip link set wlo1 up

sudo iw dev wlo1 scan

wlo1 may be different in your case (check your exact wireless extension with the iwconfig command in terminal).

To make the settings permanent, type the below command in terminal and press enter.

echo "options rtl8723be ant_sel=2" | sudo tee /etc/modprobe.d/50-rtl8723be.conf

Note:

After an OS (Kernel) update, you need to re-apply these settings again to get a strong signal.