1. Make sure you have set the correct country code using raspi configuration.
sudo raspi-config
[[File:Raspi-config-wifi-1.png|700px]]
select 'Localisation Options' and press 'ENTER'
[[File:Raspi-config-wifi-2-1.png|700px]]
select 'L4'
[[File:Raspi-config-wifi-2.png|700px]]
select the correct country then press 'ENTER'