I'll try to explain this as best I can:
In the house we have 3 computers connected to the wireless (2 PCs and 1 Mac) the problem computer is a PC and is very close to the wireless hub.... the other PC is quite a distance away and has always struggled getting a good signal (which we thought was understandable). Whereas the Apple mac, is pretty close aswell.
The apple mac is the main computer, as in we use that computer to alter the airport settings etc... AND it has never had a single signal problem or encountered any problem with connectivity.
so if comparing the problem PC with the Mac, then the mac does get good connectivity even when the problem PC has low-and-no signal.
But since the other PC has always struggled with connectivity, I cannot be sure if the problem is the same on that computer.