I am going to fit an FM radio aerial to my 2004 Compass Corona, the one I have bought has a red wire as well as the coax cable. Can anyone tell me what this is for and do I just connect it to a live. If so should the live be permanent or switched from the radio?? Thanks in anticipation.
The red wire enters the aerial mounting box which has a PCB inside and is soldered to it. Would this be the amplifier you mention?? If so I will connect it to the blue wire and fingers crossed!
Birdman is correct. The single wire you have on the aerial is to power the integrated pre-amp; the ground connection simply uses the screening of the aerial plug to complete the circuit. The accessory wire on the radio is designed to provide a switched 12v output while the radio is on only.
While this wire is usually blue, I have had a few where this hasn't been the case. I would either check in your units manual, or it's simple enough to check for switched 12v with a multimeter; there could even be a wiring key label on the device or the wiring itself may have a small label on each conductor.