AM radio interference with '94 Range Rover.

What position is the ignition switch in for this?

Also, where does the radio earth run to? It might be worthwhile taking an earth straight from it to the body incase it's using the arial for an earth just now.

Also, assuming your car has one, check the suppressor in the distributor and see if it's good - the only useful way to do this is to replace it I'm afraid.

Also you might want to try fitting a ground loop isolator to the radio, but that's a long shot.

P.

Woo. If the engine is off then it is not engine interferance but I'd go for a busted aerial connection. AM radio should be a big woosh noise if no station is being recieved. (FM goes silent) On my '97 HSE the AM and VHF aerials are seperate connections so it's probably either fallen out or something has chopped the cable.

nigelH

Sounds like the aerial is disconnected or the wire is broken. It's picking up what stray signal it can and opening the door lets in more of the signal.

The AM receiver will keep turning up the reception gain until it gets a strong signal. If there's no signal it'll keep on increasing the gain until either the background noise provides a strong enough signal or it hits maximum gain.

There should be zero Ohms between the aerial itself and the centre pin of where the aerial wire goes into the radio. The radio needs to be earthed and so does the aerial mount.

That is not necessarilly true, some aerials have a small value capacitor in the centre pin of the plug

Terry

I'm confused about where the AM antenna is. Not even sure about the FM either. Could the FM antenna be on the left and right rear windows? I'm thinking I bumped something while obsessing on window cleaning.

The radio aerial (I think there is only one) is built into the rear o/s side window on later RRCs, looks a bit like a HRW element. I thought it was built into the glass itself, but maybe it's on the surface and vulnerable to damage like the HRW elements are. I don't know about the difference between AM and FM reception, but perhaps you have damaged the aerial element and one is just more tolerant of a crap signal than the other.

AFAIK all the later classic Rangies (mine did anyway) used the heated rear screen as an aerial if you loosen off the rear edge of the headlining you will find an aerial amplifier with the coax cable plugged into it close to the speakers FM works quiet well even if this unit is U/S. I would suggest you check for a power feed but the circuit diags I had looked buggerall like the setup so in the end I had to forgo TMS and stick to FM only thinks :- I really must sell my old manuals= haynes and electronic Derek

I couldn't figure it out, drove it into the radio shop. he swapped the AM and the FM antenna and no noise now.