My son, who nothing deep understand of electronics asked me do the certain Youtube file is something realistic. There guys are demonstrating a very simple but effective 2,4 GHz antenna construction. My verdict, the said about 5-10 km distance is slightly bold, but indeed the distance is hardly boosted in comparison with normal "duck-neck" antenna. So, here is the description: Take a zincked 6mm steel screw rod and nuts. Produce a round washers with center drill of 6mm from copper plate 0,25-0,3mm thick. First washer is 90mm diameter, second 68, third 54, next 38, then three pieces 37mm. Any of them must be fixed between two nuts on the center-rod. Distance between first and second is 11mm, next 12mm, next 32, next 28...32 (best 30), and two last identical to this. The SMA connector or alternatively TV satellite cable connector is soldered into hole in the first washer, what is situated 10mm toward center from outside edge. The central hot-wire is going symmetrically through this cable embalage toward the second washer, where it is soldered to the nearest point. Its not demanded but is useful if first washer have a outside circle the skirt, 15 mm wide at all perimeter. But actually, it may be omitted. Actually, I had only 0,5mm copper, but still it works well. Probably, it may be produced of PCB as well.

 

Hello,

The construction of a cantenna would be easier.
The EDUCYPEDIA has a lot of information for wifi antennas:
Biquad antenna
Cantenna
WIFI antenna applications
WIFI - WLAN antennas
WLAN Antenna Tools
WLAN-Biquad Antenna
WLAN-Parabola

Bertus