Do you know in which side the wlan receiver antenna on archos 7 HT is located? I'm just wondering if it will affect the signal strength received if we cover the "spot", e.g. with our palm.
Slashgear has an article with a set of pictures showing the internals of the Archos 7, Slashgear: Archos 7 Home Tablet clears FCC picture 6 on this page has the wifi module and antenna labelled, unfortunately as I don't have one I can't quite work out the orientation of the parts in that picture as to how they relate to the full device, you might be able to.
There are also a number of videos on YouTube and elsewhere on the web of it being taken to pieces by owners where you can see the internals, search for something like "archos 7 disassembled" to find them.