I was suffering with wifi black spots, even browsing the internet resulted in slow and sometimes non existent signal.
I uninstalled my other wifi devices, plugged this into a usb11 , installed the software, it gave me 3 bars just on the desk, I put it on a higher shelf and it has been full power since.
I have also noticed that other devices can get internet everywhere else in the house and garden with at least 3 bars.