Weak wireless connection on IMAC

[DerJapaner]

I have an Imac, connected wirelessly to Time Capsule/Airport. When looking at my signal I mostly get ONE bar, sometimes none and I have no idea how to fix it. Very rarely the connection speed/bar signals go up to 3 or 4, but then go down after a short while again.

I tried the following already:
i) placed my MBA right BEHIND the Imac and it got 5 bars (and double connection/download speeds). Network settings on both are identical.
ii) tried to strengthen network through placing a Airport Express as relay in the middle of the distance ... no impact.

So I am assuming it has to do with the Imac settings/hardware.

As I am still pretty new to the lovely Macworld I truly appreciate your help on this

 

[Muncher]

That's really strange. There's probably something going on under the hood, with settings you can't see/change. It could be a driver problem, or even a problem with the hardware. Maybe you should bring it in to an Apple store.