I've been searching for a while but don't get it. Here's the problem. I am using a ethernet for going online at home. I can't use my router because the wall is too thick and i can't connect. However, i would like to use my external HDD as Time Machine. I do not want to connect it through USB. I found something call AirPort Extreme Base station that i can connect my HDD using USB and backup through wifi. Is there something similar to this that is cheaper?