I have had a good look around and cannot find a specific answer.

The MacBook connects to the internet via a Netgear wireless router, works just fine.

I have a largish hard drive on my old G4 that I have set-up as a Time Machine drive, the G4 has no wireless so it is connected directly via ethernet (directly to the MacBook - not the router)

Both machines have similar IP addresses and are set to use the same subnet

Whenever I power up the G4 and connect the Ethernet to perform a TM back-up, my Airport connect runs down to zero, its fine once I disconnect Ethernet again.

Its annoying but if there is a solution that keeps both connections active then I'd be a little happier

Thanks all