Technical radio interference

[harrytherid]

how can I best get rid of radio interference when the ignition is on? Presumably improve my grounding but how to best do it. My stereo is a philips CEM3000B and my Ducato is a 2007, 130 multijet motorhome and my antenna is a shark fin on the roof with the lead running down the windscreen post. The original on the side became broken and now disconnected and shortened for use as an aid to getting up to clean the windscreen. Was very similar problem while whole.

 

[Anthony489]

Hi

Do you have a metal roof where your aerial is mounted, or something else like fibreglass ?

What exactly do you mean by a shark's fin ? A simple whip aerial for FM should be about 700 mm long, anything shorter is more difficult to get to work well without a powered pre-amplifier built into its base.


Are you wanting FM reception, or DAB ? I'll assume not LW or MW as the UK transmitter network is pretty poor these days and not likely to improve.

The Ducato's engine management system radiates rather more noise in the FM band than it should, in my opinion. However, the simple whip aerial above the windscreen used by thousands of panel vans is normally OK, i.e. reasonable reception should be possible on the move.

 

[gm6vxb]

Also have a 2007 motorhome and radio reception (AM/FM) can be very poor depending how close to the transmitter you are.

The main source of interference seems to be from the ECU, and without major modification is not curable without major modification to every wire coming out of it.

The problem is the main oscillator (clock) in the ECU. It runs as a square wave. As such it is a good harmonic generator so a broadband noise source.


Moving the antenna to the rear of the van might help, but from experience running wires in motorhomes is not an easy 'DIY' job. I havea second radio mounted in the rear of the van and this does not suffer from the same interfence as the radio in the cab. Has it's own 'stick to the window' type antenna.


If you have the antenna mounted on the fibreglass section of the roof, you could try adding some aluminium tape connected to earth and the antenna mounted onto it, but suspect you will still have problems (been there, done that)