New to the forum with a question that has been stumping everyone I know.

I have a 2004 F350. I am a ham radio operator. If you aren't familiar with that, it is similar to 2-Way Radios. When I talk on the ham radio, at idle only, my transmitted audio from the ham radio is picking up a buzzing sound. This is not normal. Typically, when this happens, it means the alternator is going out. However, it that were the case, the noise would continue when you accelerate and change pitch in tune with the RPM's.

I was just curious if anyone knew of anything electrically or otherwise that could be making this noise.

Forgot to mention, if you turn some of the electrical devices off inside the cabin, the noise also goes away. So, for instance, if the heater is on high, I get noise, if I turn the heater down, the noise goes away.

Thanks in advance!

 

what you are getting is called EMI (Electro-Magnetic Interferance). An alternator with the diode trio going out causes the same thing. basically what it is, is AC voltage static in the air interfering and conducting on your radio's wires.

where did you route the wires for the radio?

the fix is to take a wire, and run it in the harness along with the wires for your radio. this wire MUST be a bare wire, not insulated, and not powered, run it straight to a ground. or an easier way to do it is to wrap your power and ground wire in aluminum foil (reynolds wrap). Both ways are used in Class 8 trucks for the Data Bus to sheild from EMI's

 

Thanks a lot for the reply!

Are you saying that the alternator is going bad at this point and that is what is causing the noise?

Also, on running the bare wire: that bare wire would not be connected to anything at all, just running along side or with the positive and negative wires for the radio, correct?

Man, thanks again!

 

well, to check if your diode trio in your alt. is going bad (which is a bad alternator), take a multimeter set on AC voltage, and stick both your leads on your battery(s) POSTS, not terminals. you should see no more than .3AC Volts. if you see more, your alt. is going bad. it's no longer rectifying your AC voltage to DC.

the bare wire, the only thing you want to hook that to is a ground, and run it along your positive and negative wires. if you can, wrap it around the pair leading up to the radio, i think the normal is 2-3 wraps (times around the wire) per 2-3 inches of wire. with class 8 trucks this is known as a "shield wire"

not a problem, let me know if this works. it works in class 8 trucks so you should be in good shape