If you want to increase the reception of your antenna, here's how.
I've already explained how to build a directional antenna using a cylinder box, now we are going to improve an existing antenna.
Cut out in a cardboard paper the two shapes matching the images underneath (you may also glue 2 pages together to get something similar to cardboard).
At the back of the rectangle shape, glue an aluminum foil, and at the front clip on the rounded shape : the bumps of the rounded shape go into the slots of the rectangle shape. Pierce at the tow crosses to let the antenna through: you get the result showed underneath.
For more info (in French) and photos, read the post on Hardware.fr forum !
In the Hardware.fr post, it is noted to use wifi sistr, to measure signal quality: this is a Windows software.
On Ubuntu (and derivtives) to know signal quality, we used to type in:
$ sudo iwlist wlan0 scan | grep -E "Quality|Channel"
iwlist is deprecated and replaced by
iw s o we shall type in:
$ iw dev wlan0 scan | grep -E "Quality|Channel"
Happy wifi reception! !