A.M Stations in Radio

[mprus]

Hi everyone,

I currently have a 2004 mazda 3 GT. One of my problems I have is that my A.M radio stations are very very static. I hear my RPM's through my radio doors and the faster i go, the more annoying and higher the sound gets ? Im not sure where to start. If im idling, then the radio is crackling, and when i drive its a high whinding noise with cracks which makre very hard to hear anything from A.M station.

The F.M is good, but I know it can be better if i solve the A.M problem.

I have no amps, nothing. Just stock.

Any help ?

To me it seems like a bad grounding point, but where to start ? :(((((

[mprus]

help Please ?

[SonicBoy]

Have you tried to see if the antenna is hooked up correctly? Maybe pull the radio and trace the antenna wire.

[sas]

I thought no one uses that waveband.
AM –Amplitude Modulation, it catches all electrical noises. Plus, the radio has the automatic gain adjustment. If you have a “shark fin” it’s very possible that AM signal is too weak and radio amplifies all noises. Also, could be a bad shield contact of the antenna cable, or more exotic causes: a shooting ignition coil or noise from alternator.
Can’t remember, when AM and there are no stations , the head unit disables the amplifier or not. If you can hear a noise in free zone (between stations), disconnect the antenna from head unit. If noise is disappearing then look the antenna, if not then this noise is coming from supplying wires. There is the contact of the antenna shield on connector, look how it's springy.

[mprus]

how do i know which is the wire from my radio ...

its not my antenna.its original its been like this last 3 years and now its ticking me off,lol

[sas]

The shield contact is located on the antenna connector plugged into head unit, central contact is signal itself and side contact is the shield. Without shielding the whole cable will be as antenna and all noises from lying nearby wires will be received by radio. Noise from alternator exists in all cars , but this noise is suppressed by capacitance of the battery. You could experience the higher noise level if there is a bad positive or ground wire from battery or alternator.
Don’t know how I can help more, to detect the nature of such noise you need in o-scope and good electrical skills, I’m afraid it’s beyond of your abilities. Do check it visually,
shake wires, maybe you can find it.

[tech@custom647]

sounds to me, stock radio is going bad..
replace it and you will get am back