car radio help needed

[timetraveller]

hi all
probably been done a thousand times but here we go again
i have a positive earth traveller that i want to fit a positive earth period radio to
i want it to switch on and off with the ignition
from the back of the stereo there is a red wire with an inline fuse..where would be the best place to attach this?
there are no other wires coming from the back except the speaker wires
do i attach an earth to the radio casing then to the cars metal body?
im confused as to where the radio is getting its power and how its earthing but i dont want to change the vehicles polarity
any help appreciated
thanks in advance
neil

[bmcecosse]

Just attach the red wire to an ignition fed source - and yes earth the casing and the aerial base.

[MarkyB]

In the fuse box, on the bulkhead, under the bonnet there are 2 fuses.

One is live all the time the other is only live with the ignition on.

On my car which is fairly unmolested, the right hand fuse is the switched one.

Use an in-line fuse too.

[timetraveller]

hi all
thanks for that
anyway radio installed and working however there is a lot of interference when the engine is running
(sounds ok when engine is off)
any advice to stop this
thanks
neil

[bmcecosse]

Fit suppressors! Coil/dynamo and fuel pump. And - suppressed spark plug connectors with 'carbon string' HT leads. Also - run the aerial lead as far away from the engine bay as possible - and make sure it is earthed at it's mounting point.

[timetraveller]

Fit suppressors! Coil/dynamo and fuel pump. And - suppressed spark plug connectors with 'carbon string' HT leads. Also - run the aerial lead as far away from the engine bay as possible - and make sure it is earthed at it's mounting point.

fit what !!
where do i get them ?
what do i do with them ?

is the interference because of the positive earth polarity of my car ?

if it involves a lot of messing around and expense would it just be easier converting to negative earth ?
after all im just trying to fit a radio at the end of the day,and i done it a hundred times on neg earth cars
neil

[bmcecosse]

Suppressor = capacitor fixed across the troublesome 'noise' maker. Nothing to do with the +ve earthing.

[MarkyB]

is the interference because of the positive earth polarity of my car ?

Shouldn't make a difference, though newer radios may have better suppression built in.

Most radio interference is caused by something sparking which puts out a big burst of radio frequency noise.

This can happen at the ignition points, the pump points, the spark plug leads and whatever type of generator you have.

There are special capacitors you can fit to these and plug leads and caps for the same purpose.

Not expensive, and you may not need to suppress everything, listening to the interference will give you an idea of what is causing it.

[timetraveller]

so are there different suppressors for the different components or are they a universal thing ??
where can i get the suppressors from ??

[bmcecosse]

Ebay is your friend........ http://cgi.ebay.co.uk/New-pack-Car-Dyna ... arParts_SM This and many others are found simply by typing 'suppressor' !! Including I see an 'inline' unit to be fitted in the power supply - may be worth trying. Personally - I don't see how you can hope to hear the wireless above the music from the screaming A series and it's gearbox ?

[timetraveller]

Personally - I don't see how you can hope to hear the wireless above the music from the screaming A series and it's gearbox ?

ha ha you havent heard my taste in music

i just bought the suppressors from ebay so hopefully i can start to eliminate from there

thanks for your help
neil

[timetraveller]

Ebay is your friend........ http://cgi.ebay.co.uk/New-pack-Car-Dyna ... arParts_SM This and many others are found simply by typing 'suppressor' !! Including I see an 'inline' unit to be fitted in the power supply - may be worth trying. Personally - I don't see how you can hope to hear the wireless above the music from the screaming A series and it's gearbox ?

wow whats going on

i bought a set of suppressed silicone plug leads which greatly improved the radio but still interference
i then bought and fitted a 10 amp inline unit that doesnt work at all on negative earth and if i change any wires it blows the fuses
i also bought the above ebay dynamo radio suppressor but i cant see where it should go,looks like a condensor with one black wire coming out......????

any help please

[crossword]

Neil,
the suppressed spark plug leads have improved ignition noise and given you an idea what it sounds like . You do not mention any suppressed coil lead . That would also be a good idea .
The dynamo suppressor ( condenser ) you have should have the main body fixed to the metal of the dynamo and the flying lead to the dynamo output .( Thick lead ) Dynamo noise is a ' rushing' noise that changes with engine speed .
Further improvement may be obtained by adding capacitor across the fuel pump points . Burlen fuel systems , the owners of the SU name , do sell these quite cheaply .
Finally if your radio is AM i.e. long & medium wave it will be more susceptible to interference from your car than a more modern VHF unit .

I wish you luck ,

Regards Andy