A.M Radio and CB Noise

jarch · Jul 22, 2011

I hope a fellow Bronco Enthusiast can help.

When the Engine on my Bronco (302) is not on, the A.M. radio and CB work fine. When the engine is running, I get severe noise so much so that I can't tune in any A.M. stations and the CB does not get reception. The noise appears to have a different pitch with engine RPM. I do not have a capacitor on my voltage regulator. Both the radio and CB are connected through the Fuse Box. The ammeter needle also fluctuates.

Does anyone have a suggestion for a fix and if it involves a noise supression capacitor, can you please provide a reccomendation for a good one and help describe how and where to install it.

TBS-POPS · Jul 22, 2011

YUP! you answered your own question. Radio Shack or other electronics store and put it in the power supply line to the radios.

DirtDonk · Jul 22, 2011

Not only that, but add a few grounding circuits to the whole truck. Broncos are particularly susceptible to radio noise, but I think especially after all these years have added their corrosion to the mix.
The fuse box is a nasty collection of rusty contacts, and the voltages are probably lower than optimal even at the main feed lines anyway.
Add to that the missing radio noise suppressors (at least 2 of them), and you've got a recipe.

One goes on the positive side of the coil and one goes on the Yellow wire at the voltage regulator. My PO added four more, to various points on the truck. Including two that were of different ratings, simply bolted to the body panels!

Paul

chase8266 · Jul 22, 2011

is your alternator old does it need to be replaced?
the wires going to and from alt and voltage regulator in good shape?
have you always had this problem?
or did it happen when you changed something?

p/s been cdl driver for 10yrs now and the only time i thought i needed a noise suppressor is when that cb was a bad radio.but i have not put one in my bronco yet so i can only help you so far with that

broncnaz · Jul 22, 2011

Other things to also consider is spark plugs and wires if you run non resistor plugs and solid core type wires you'll get noise in the radios. So make sure you have resistor plugs and wires.

Viperwolf1 · Jul 22, 2011

The mechanical voltage regulator is a big noise maker. Consider upgrading to an electronic one. A point set condensor would make a good noise suppressor.

markperry · Jul 23, 2011

I was having this same issue. When listening to my AM sports stations I got a lot of really load noise that sounded like the distributer was in the radio.

I happened to be messing around with the antenna one day and noticed that the wire from the antenna to the back of the radio was hagging on by a thread. I replaced the antenna and the noise was gone. Something to check!

69for5 · Jul 23, 2011

I've had that whine before with the rpms, and it was the ground.........be careful tho, if u take the radio out you have to remove the transfer case, which leads into removing a door, then one leaf spring and the front bumper

jarch · Jul 23, 2011

Thanks gents. I will try these - probably in order of easiest first

I do have spare points capacitors. How would one of these be used as a noise supressor? Would you connect in series through a hot wire to the device?

DirtDonk · Jul 23, 2011

69for5 said:
...be careful tho, if u take the radio out you have to remove the transfer case, which leads into removing a door, then one leaf spring and the front bumper

You forgot the roof too! Or did you figure out how to get the radio out without taking off the hard top, windshield wiper and passenger seat?

Hah! Good one 69. That's the perfect description of any small Bronco project.
The old "one thing leads to another" scenario.

Paul

DirtDonk · Jul 23, 2011

jarch said:
...I do have spare points capacitors. How would one of these be used as a noise supressor? Would you connect in series through a hot wire to the device?

Nope. More like in parallel. I think? Might have my phraseology mixed with my metaphors, but I think you're on to it.

Just tap the wire from the capacitor/condenser thingy into the circuit in question near the termination point. Then ground the body/case of the condenser to the nearest body part.

On both the coil "+" and regulator's "A" wire (Yellow), the factory had them pigtailed off the ends. So the coil had the noise suppressor on a couple of inches of wire, and mounted to the coil's mount. If you're using a stock coil mount still, you can see the little tab with screw hole.
Same for the regulator. A short (3 or 4 inches) wire came out of the same connector as the Yellow wire and the suppressor was mounted to one of the regulator's attaching bolts.

Paul

Steve83 · Jul 23, 2011

I'd always start at the battery. If you don't have good connections there, nothing else will work right. Read these captions:

Then inspect the alternator, ignition system, antenna wiring, & radio grounding. If all that is good, you shouldn't need any more noise filters. The stock capacitor goes near the voltage regulator A terminal. If you have persistent ignition noise, add one near the coil positive.

A.M Radio and CB Noise

jarch

Newbie

TBS-POPS

Bronco Guru

DirtDonk

Bronco Guru

chase8266

Jr. Member

broncnaz

Bronco Guru

Viperwolf1

electron whisperer

markperry

Bronco Guru

69for5

Full Member

jarch

Newbie

DirtDonk

Bronco Guru

DirtDonk

Bronco Guru

Steve83

Bronco Guru

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