do the signals from broadband routers travel "up" (check details)?

Question

my main computer is in the baasement can the signal reach the others upstairs?

Answer 1

Yeah, the signal is sent outwards 360 degrees, like the light from a light bulb. However,the signal obviously gets weaker the further it travels, and if the signal has to go through several floors before reaching the other comps then you may find it is too weak.

Answer 2

Actually it depends upon the antenna design and orientation. Most wireless access points do a better job of horizontal propagation than vertical when the antennas are in a vertical position. The majority of the signal propagates at a right angle to the antenna. If you want better vertical signal propagation, flip the antennas so that they are horizontal.

Specialized antennas can greatly extend the range of a wireless network. I've used parabolic dishes to extend signals from a standard WAP to over 20 miles line-of-sight and yagi or "cantenna" type antennas for 4 or 5 miles. With this type of antenna the trade off is a much narrower footprint of usable signal. If you're even just a few feet behind a parabolic dish you may not have any useable signal at all.