On the R32 the antennae are the fine wires in the front and rear windscreen.
Is your Pioneer deck an aussie or jap model? The jap models only pick up a few aussie stations as the bandwidths overlap a bit.
If it's a jap deck you could have a bandwidth shifter fitted.
If it's an aussie model then it may not have been fitted correctly. I think there is an antenna booster in the boot of some if not all R32s. I've been told the black and red wire, that is taped to the antenna coax that plugs into the back of the deck, needs to be wired to the power antenna (blue) wire that comes out of the deck so the booster can get 12 volts.
When the factory deck is replaced with an aftermarket deck you need an adapter plug.
The factory plug has 2 pins and the a/m deck only uses the pin from the rear windscreen.
One suitable adapter on the market is Aerpro AP348A.
I hope that helps.