Same again, here...
TP-Link TD-W8961ND
Windows 7 PC
Mac-mini
iPad 2
iPhone 4s
2 Airport Expresses (1 old, 1 new)
I got the router and second AE (for another room) about a month ago to replace an aging 'g' Netgear (which, although dying occasionally connected to everything and the AE worked fine). Had the same problem from the start (only now properly investigating):
- Plug in either AE - light goes green
- Shows up in Airport Utility, speakers on all devices
- Fine for 30-40 mins
- Disappears from all devices and Airport Utility but light stays green
- Only way to resolve is to unplug and plug back in.
Strange. Pretty sure it's not the AE as I have one brand new and one old (which until we got the new router worked fine), and it's unlikely they'd both start exhibiting the same behaviour. So that leaves figuring out potential settings on the TP-Link.
And I don't think it's channel interference as (a) using iStumbler I see all the devices in the area are on either channel 1 or 11 - I've set the router to channel 6, and (b) other people are experiencing the same problem, and it's unlikely we'd all have the same conditions around us.
I'm not too sure about the various wireless settings - they're all a bit beyond me, but will continue with trial and error until something works... will let you know if I find anything.