FM band expander on JDM imports

[Trevor]

Hi again Joe,

I do not understand how signals are being picked if they fall within the original Japanese tuning band width. The connecting cable between the expander and the tuner should be fully shielded so that no signal should be available at the tuner frequency. The only signal available should be as modified by the expander.

I gather Phil has his expander remote in the boot close to the vertical aerial. The long lead in may be providing a means of entry for signals at the original frequency direct to the receiver. Earthing of the lead in shield could be faulty resulting in an earth loop. The shield as part of the vertical aerial must be in contact with the body shell at the entry point of the aerial and also to the receiver aerial socket earth.

If he has the expander case earthed separately in the boot he should try removing this connection so that there is earth and negative connection only via each end of the cable shield. This could otherwise be providing an earth loop condition. If the expander is provided with a designated earth lead this suggestion will not apply.

Regards, Trevor.