it is nice to get an graphical overview what wifi wlan networks access points one is surrounded by.

also good to know what direction to point antenna/laptop to have best reception.

because this allows to fine-tune what channel best to use, to minimize interference with other access points and so on.

hostnamectl; # tested on
   Static hostname: DebianLaptop
  Operating System: Debian GNU/Linux 9 (stretch)
            Kernel: Linux 4.9.0-12-amd64
      Architecture: x86-64

su - root; # become root
apt update;

bash terminal version:

connect to the network of which one wants to measure db reception (connection need already to be established)

to scan for wifi networks from bash, check this article.

to measure signal strength keep reading:

apt install net-tools; # install net tools like ifconfig
ifconfig; # show network interfaces
# wifi interface will (usually) start with "w"
# alternative:
ip addr show; # show network interfaces

# shortcut for /etc/bash.bashrc
alias loopwifidb="while true; do iwconfig wlp3s0; sleep 1; clear; done;"

wlp3s0    IEEE 802.11  ESSID:"xxxx"  
          Mode:Managed  Frequency:2.422 GHz  Access Point: 9C:C8:FC:31:xxxx  
          Bit Rate=6 Mb/s   Tx-Power=22 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:on
          Link Quality=33/70  Signal level=-77 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:18  Invalid misc:14   Missed beacon:0

gui way:

apt install wifi-radar;
wifi-radar; # start

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