Radio Crackle

[Arthurdaily]

Fitted a new radio, well an old radio cassette actually, and it's great - but the radio crackles when it's running. I first thought it was the aerial, which sits on a fibreglass wing - but after putting wire from the base of the aerial to the battery earth it STILL crackles (so I removed it - is the aerial supposed to be earthed??).

What is my FIRST thing to do to try and stop the crackle? Please.

[bmcecosse]

Yes - it MUST be earthed. Put a capacitor on the coil feed wire - at the coil. Maybe another on the fuel pump wire.

[Arthurdaily]

I imagine that a thickish wire direct from the metal plate under the aerial, where it would normally touch the metal wing, direct to the earth of the battery would be suitable for the aerial earth yes?

As for the capacitor for the coil... I'll have to read up on that...

[Arthurdaily]

Checked again, an earth from aerial to radio makes no difference to the noise whatsoever, I'll check out this capacitor business. Will spark plugs make a difference? i.e. depending on the gap / condition etc.?

[bmcecosse]

Not really - the HT leads are probably 'resistive' type. It doesn't matter anyway - because you will never hear the wireless when the engine is running......

[Arthurdaily]

ha ha!

[moggiethouable]

The first thing is the antenna will work a lot better in terms of reception if it has metal underneath it.
The best spot is smack bang in the middle of the roof, but this is not practical,so the next best thing is a metal wing.
So its not just about earthing but also the groundplane (metal) beneath it.
You can fit baco-foil or a metal sheet under the fibreglass wing.
With the engine running grab hold of the antenna cable tightly, if the interference is reduced fit a ferrite ring as per photograph, just loop the cable in and out of the ring and refit to antenna.
Do the same with the earth and supply leads, if there is improvement,fit a ferrite ring on that/those cables also.
If there is no improvement fit a suppression kit http://www.nexxia.co.uk/products.asp?s= ... uppression
Personally I am with Sir Alec Issigonis when he said he saw no need to fit "domestic appliances" to motor cars [frame][/frame]

[Arthurdaily]

Thanks Moggie, yes, clearly a plastic wing is an issue - interesting idea about metal underneath... I will do that and then attach that ground to an actual metal car structure. Also going to try an internal aerial - heard some good reports and they are only cheap, so worth a go.

Thanks, ArthurD

[neil4030]

My minor already had a domestic appliance installed at the time I bought it, with an aerial fitted to the inside of one of the rear windows i.e. a proper window mounted aerial that works well enough. However, I too had a crackle and I solved it (very rare for me) by fitting a set of suppressed ignition leads. The ones fitted looked the same but were obviously not. Roy is correct though; impossible to hear the appliance even on fast spin above 20 mph and anyway, I would much rather listen to my lovely engine together with all the nice friendly squeaks, rattles, groans, bangs etc.

[lambrettalad]

my radio sounds FAB ,using a stick on rear window aerial ,two speakers at the front two on the rear shelve ,can hear it fine at 60 but not so well with the window down No suppressers needed