Head unit wiring

[quattro estate]

Hi to all
I have tried to connect a pioneer head unit with some success but the radio reception is almost nil. All other modes work fine. I have a green live wire from the car but cannot see where it would connect to the unit.
Is there an amplifier wire to connect, I have found a red wire from the rear roof aerial connector but that was red and short with a tab with auto written on it.
ps mine is an avant 1994 model
cheers

[M2ki]

White wire is aerial amp.

Single white wire near the aerial cable.

[quattro estate]

Cheers for the info