bloddy mud

Yup title says it all. What causes this

01xjMontucky

You mean like a consistent hum that increases with RPMS? Usually it's alternator feedback. They sell filters to cancel that noise

bloddy mud

Huh...never herd of that I'll look into it. I've noticed my cb picks up the hum to. And I have beliefs my alternator is about to choke

mdnov

It can also be caused from your spark plug wires.

PNWjeeper

When I installed my the amp for my sub some one told me that the power wire might pick up some engine noise and that installing a fuse near the amp (as opposed to near the battery which is what is suggested) will eliminate the noise. Whether or not thats true I don't know, I don't have any noise coming from my sub that isn't supposed to be, and I have it setup the way the kit suggested. Also if that applies to your issue I don't know, I'm just throwing out an idea.

01xjMontucky

this is a dumb video, but for stereo and amp related:

from a random site: In my experience, Ive found that in systems that have noise problems, a ground loop is the culprit nine times out of ten.

another random site: One thing to check on every feedback problem in vehicles is your ground connection of the equipment affected. Make sure the CB radio has a solid electrical connection to the frame of the vehicle. If the cigarette lighter adapter is just the plug in type, it makes for a poor connection electrically. I would try and hard wire the radio first to see if that takes care of the problem.


I also read it can be radio frequency noise as opposed to alternator whine (which is nearly always poor wiring, especially grounding).

You wouldn't get RF noise in your stereo while playing a CB, only while listening to the radio. hence Radio Frequency noise.

regarding rf noise: (from a random site) Your title indicates you have a feedback problem but the post indicates it is a problem with RFI. Most likely what you are picking up is the noise from the spark plugs. This is a common problem with low cost and low quality CB radios that don't offer any kind of RF noise suppression. Alternator whine will come in over the DC power cable and will still be present with the antenna disconnected, but RF noise coming from spark plugs or fuel pumps or other noise sources comes into the receiver through the antenna. You can determine if this is the case by tuning your AM radio to an unused frequency and see if you are able to hear the same or similar noise. Your factory radio may have noise suppression so you may have to perform the test using a portable radio. Most likely the most effective solution would be to replace the CB radio with one with a noise suppressor or "noise blanker". The other solution would be to track down the noise source and repair or replace the source. If its spark plug noise, sometimes you can reduce or eliminate it by replacing the plugs and wires, cleaning electrical connections related to the ignition system and verifying that the body of the vehicle is well grounded to help keep RF noise inside the engine compartment. Even if you do all that, you may still find that your CB radio will pick up the noise.

so.. yeah - crappy wiring job, cheap cb, worn electrical connections, etc.

jeepforum topic that's maybe related: http://www.jeepforum.com/forum/f20/h...eakers-962550/

bloddy mud

Cheap radio. It's a veep that plugs into the cig outlet. So you got that right on two things. And could be my plug wires cause they are quite old. I do have subs but it done this after few months of the subs

JustJoe

If you have an Amp check your ground. Try to make short as possible with a thicker wire. Also the grounding point, sand off any paint to get a good ground.

Run your RCA cables away from 12v + it will pick up noise as well.

FYI you should always have a fuse at the battery under the hood for amp power wire. Use grommets when passing through the firewall. Good luck

CCKen

Check the bonding strap that goes from the firewall to the left rear head stud/bolt for corrosion. Remove the bolt from the firewall and inspect the firewall metal for corrosion, the bolt for corrosion, the bonding strap, and the bonding strap terminal end for corrosion. Corrective action is straight forward.

Remove the nut from the cylinder head stud/bolt that secures the bonding strap there. Agan, check the connections there for corrosion.

Danno25nh

RF refers electromagnetic radiation at a specific frequency range. His radio does not emit RF it receives RF, additionally, if the source of RF were his radio it would not change pitch with a change in engine speed.
Check your grounds,look at at you plug wires, and bypass the cigarette lighter.

salad

^^^^ This. In later model years this isn't even referred to as a ground, but a bonding point specifically to reduce RF noise. The braided strap is prone to corrosion and can die pretty easily.

The suggestion to check spark plug wires was also a good one. They should be carbon resistor type with a silicone insulator. If someone got clever and put actual wires (copper conductor) on... there's the problem.

bloddy mud

All right guys i got a todo list with possiabilties. Thanks another question didn't wanna make another thread but has anyone used on of these? Are the rca cables input or out put?

bloddy mud

for the radio/CD player for those who may not know what it is it's an aux port that plugs to the back of the CD player. I hook it up and I don't get anything out of it

01xjMontucky

I'm not the one asking haha. I just thought maybe it would receive interference like the cb could. Danka

bloddy mud

Ya never mind bout the aux jack. That thing was junk so I took it back and got a glass pack