Can penetrate 2 to 3 floors, if you are talking about wireless Internet access (wireless router) in the local area network, in the absence of barriers 50 meters signal has about 85%, if there is a barrier, such as the wall between the room, the ceiling between the floors, then the signal attenuation is more severe, a wall is estimated to decay about 20%.
According to the IEEE802.11 standard, the maximum distance that the general wireless router can cover is usually 300 meters, but the scope of coverage should mainly depend on whether the environment is open or not, in the case of the device without an external antenna, about 300 meters in the field of view; If it is a semi-open space, or an area with an insulator, the transmission is about 35 to 50 meters.
If you use an external antenna (to do the link), the transmission distance can reach 30 to 50 kilometers or even more, depending on the gain of the antenna itself.
Therefore, it needs to be applied according to the needs of users.
Two floors is about 6 to 10 meters, the general router can be, that is, the signal will be weakened. I don't mind getting a newer model. Depending on the location and signal strength, the estimate of two and three antennas is better.