The location where you place the wireless router is the most important part when it comes to increasing its signal strength. In fact, everything in the house – doors, walls, windows – are barriers to WiFi signals.
Thus, if you live in a two-story house, placing the router on the second floor offers more WiFi signal extension.
The antennas of the device work something like umbrellas, the higher you run them, the more signal they will emit.
Just keep in mind that floors slow down the signal, so it’s not a good idea to leave it on the floor – especially if you want a strong WiFi signal downstairs. Doors and walls are a nuisance as well. This means that if the router is in the center of your home, the better it will be for you.
Even if the router is in a room with the door closed, open it, to make it a less obstruction.