Time for acton – experimenting with your Alfa card

Perform the following steps:

1. Reboot your computer and do not connect your Alfa card to it yet.

2. Once logged in, monitor the kernel messages using the tail command:

   

3. Insert the Alfa card, you should see something which resembles the following screenshot. This is the default regulatory settings applied to your card:

   

4. Let's assume that you are based in the US. To change your regulatory domain to the US, we issue the command iw reg set US in a new terminal:

   

5. If the command is successful, we get an output as shown (in the following screenshot) in the terminal where we are monitoring /var/log/messages:

   

6. Now try, changing the card to channel 11, it would work. But when you try changing it to channel 12, you get a error. This is because channel 12 is not allowed for use in the US:

   

7. The same applies for power levels. The US only allows a maximum of 27dBm (500 milliwatts), so even though the Alfa card has an advertised power of 1 Watt (30 dBm), we cannot set...