Radio reception & electrical intereference

[Marshy]

I know the subject of aerials in Chims/Griffs has been done to death, but what are my options for reducing interference from other electrical bits of the car?

Radio reception with nothing much else turned on is just about acceptable, but the wipers and washers make a hell of a din, especially when listening to radio 4, which is a weak station anyway.

Can I cheaply and easily suppress the wiper and washer interference? What else might I think about?

Cheers.

--Chris

[the dodo]

Chris
i see you are chimera, i have a griff with an aerial in the boot rain gutter. Are you talking AM or FM ? I have almost perfect FM, with listenable AM, if i was into cricket !
David

[JMorgan]

What aerial have you got. No problems on my 400 but an extra foil added to give a ground plane effect to improve reception, not a very good contact between the foil and the copper wire so going to try a fridge or oven grill next (not joking, need a ground plane).

[ATG]

Marshy ... have exactly the same problem with wipers. I haven't done anything about it yet, but would start by trying a 10uF capacitor across the motor's terminals (Maplin can supply ... probably for about 50p). You might need to do the same for the parking switch too as i'd guess its got some kind of sliding contact in it. No doubt car stereo shop could supply but probably more expensive and will also try to sell you oxygen reduced solid silver speaker wire that has been blessed by the Dalai Lama in order to reduce distortion.

[bertie]

In principle a cap across the offending motor(s) might help but 10uF is a bit large for fast transient suppression, you'd be better with something like a 0.1uF disc ceramic.

If it's radiated emmisions from micros or the like you might not be able to help it but that's unlikely in a Chimaera with the standard ECU.

[Noel V8]

Very simple 100% cure here guys, run an earth wire from the throttle linkage on the n/s top of the engine to the body of the wiper motor. Use the wee screws at the top of it 7mm head. top repair.

Noel V8

[richb]

OK chaps, been playing around trying to improve the reception on the Griffs radio.
I have fitted an aerial in the boot, (like the Dodo) and I now have 90% decent FM radio, but I still get some interference. Now, my theory is that it is the fuel pump. Because basically the reception is perfect before I blip the imobiliser (which turns on the fuel pump) once blipped I get bad interference - even before I start the engine.
So...would anyone have any idea what capacitor I should use to suppress the fuel pump and how/where I should wire it? In my quest for perfection I thought I might go down to Maplin this afternoon, get some bits and have a fiddle!

Rich...

[plotloss]

Rich,

Not overly sure about the size, remember fitting them to a radio controlled car as a kid and they were about 250 micro-farads so I would have thought you would need something a little beefier.

I believe you would need to wire it between the live feed terminal and the earth.

HTH

Matt.

[ATG]

You are looking to supress transients, so you don't need a great deal of capacitance so much as damn all internal resistance so that fast transients get absorbed too. Best bet is probably to go for two capacitors in parallel ... one electrolytic of maybe 10uF, and one ceramic of 0.1uF. The ceramic will have much lower internal resistance.

As per ususal, the values I've picked have come straight out of my *rse. The more capacitance the merrier here, so they'll probably be okay.