WiFi sort of dropping out periodically on iMac, doesn't happen in Windows 7 though

[MythicFrost]

Hi,

I've got an AEBS (4th gen, I think) and an iMac -- they are quite far away, but the WiFi bar shows three signals, and I get good upload/download speeds.

Periodically the internet just stops working. This issue is the same on my iPad. It's not disconnected, as it still shows it's connected to my network but AirPort utility can't find the AEBS, and anything internet related just gets stuck (like loading a webpage).

Strangely enough, I have no problems with this under Windows 7.

I considered that it could be the AEBS (apparently the 4th gen was kind of faulty for long distances?) but I'm not sure. Doesn't make sense it works with Windows 7.