installing APextreme on dual g5

so my brother's got a dual 1.8ghz g5, he just moved into an apartment where a wireless network is the only real option, so he bought an airport extreme card.

at first he complained he couldn't pick up a signal - turned out he never plugged the antenna into the back of the airport card.

still can't pick up a signal though osx recognizes his card. i told him to check if hes roomate's laptop picks up a signal in that room...

working him through this on the phone i had been looking at the DIY repair/upgrade pdf on the support site for the APE

but when i looked through the powermac g5 (early 05) users guide i noticed there was this extra fifth step in the installation procedure for an airport extreme card:

5 Attach the AirPort Extreme antenna to the AirPort antenna port [airport symbol] on the back panel. To adjust reception, you can rotate the antenna.

and theres a picture of what appears to be like a rubber stub sticking out of the back of the tower above all the ports - my brother says he doesn't see anything like that.

should that thing have come with the computer? is it even necessary?

any thoughts?

thanks!
j

thanks a lot, RGunner.

but should that T antenna dongle have come with the mac or with the airport card? or will the apple store give him one if he should have it and doesn't?