Pringles Cantenna is the popular tin can waveguide wifi antenna. No doubt if you do it properly you can boost your wifi strength up to maximum level. This is cheap and reliable diy method. All you need to have is just a skills and a little time for experiment. The most important tools is A N-Female chassis mount connector. It is the heart of the long range wifi antenna.

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N-Female Connector

The position of the N-Female inside the can also important. Since normal wifi signal operate with 2.4MHz frequency signal so need to know the diameter of the can. Then you can find the cutoff frequency.

Wifi cantenna