Why do I hear myself through my stereo speakers?

[rjparker]

Yes thats right, if I have my stereo on, and I talk on the CB, I can hear my voice through the radio. I drive an '04 International 9200 with the built in factory antenna which I don't use by the way. I also don't use the factory cb speaker either. If I turn off my radio then I don't hear my voice through the stereo speakers. With the volume muted or turned down to nothing I still hear my own voice.

My CB is a Cobra 29ltd and my antenna is a Francis I think... 18 feet of quality coax and my SWR is below 1.5 on all channels.

[25(2)+2]

Amateurs may be able to answer you better,first of all are you listening to FM, AM, or recordings? Is your radio tuned to factory specs or is it peaked and tuned? Are you using a power mike on the CB?

If you aren't using the factory CB antenna setup, are you sure of your antenna is getting a good ground?

If I'm listening to AM radio in the FL, I get sound through my radio speakers, I usually turn the radio down to talk on the CB or take phone calls.

[rjparker]

Hey thanks, I usually listen to my satelite radio, seems that the FM/AM only works once in a while, (I bought the truck used). No I don't have a power mic either, and I did not get it peaked and tuned. I use it 99% of the time for shippers and recievers, I don't worry about the police and of course I sweat bulletts at scale houses. I did not run a ground wire from the attenna bracket to the truck itself if this helps. I have to turn off my radio if I am on the phone, I can't for the life of me listen to two things at once. I can't walk and chew gum at the same time either

[kd5drx]

What your getting is called RF feed back or by pass. What it is is the signal from your CB antenna is getting into the amlifier section of your AM/FM/Stereo and bleeding into the speakers. The best way to stop it is to wrap your speaker wires around a turoid this will sheild them. The other thing is to ground you stereo system itself to a good ground. Also ground your CB and your CB antenna and make sure they are grounded to the frame. The grounding alone should help but if not check the routing of you coax from the CB to the antenna if it runs along the same path as the stereo speaker wire it would help to reposition it away from the speakers.

[rjparker]

Sorry for taking so long to get back here, kd5rx, what is a turoid ( I hope I spelled it right), I would hate to see what disgusting websites I would find if I googled this word!! You also mentioned about where I ran my coax, in my International, the factory installed one of those antenna's that work both the CB and the stereo. I never took out the cable from the factory. I just pushed back out of the way and installed my new coax. Yeah I'm lazy, pretty much like probably 90% of people. I don't know how to remove it from the truck. I don't want to mess up something else!!!

I was on the Serious channell 147 morning show on Wednesday, asking about this and the guy told me about putting a filter in my stereo. This sounds like it might work too.

Let me know what a Turoid is, I'm curious.

[kd5drx]

Is a iron powder graphite disk that is made to wrap wires around it will block harmonic freq from passing thru it. they sell them at radio shack under the name of rf chokes, or feride beads.

[Carolina Thunder]

Put the modulation limiter back into the cb, problem solved!

[rjparker]

Man, am I out of the loop!!! What's the modulation limiter??

Can I buy a dispatcher limiter?? at Wal MArt??

[BobC]

Originally Posted by rjparker

Man, am I out of the loop!!! What's the modulation limiter??

Can I buy a dispatcher limiter?? at Wal MArt??

Don't worry about the limiters because you said you never had the radio "tuned or peaked". Tuning or peaking eventually leads to adjusting or mis-adjusting the modulation limiter control.

As said in another post, your stereo is acting as an unintended receiver for the cb band. It's most likely caused by the stereo's speaker leads acting as an antenna, picking up a fair amount of cb signal power & overloading the sensitive audio preamp stages in the main amplifier section.

You need to find out if your cb antenna is grounded to the mirrors well & there's a good swr reading. If there's a fairly high swr, some of your cb's transmit power is coming back down your cable & radiating into the close by speaker leads.

If everything is otherwise good, use those Toroid cores that someone mentioned. You used to be able to find them at radio shack. They look like a square once they're snapped closed.

To use, wrap the extra speaker leads around the open toroid form as per the directions & then simply snap it closed. Put the toroids nearest the stereo as possible. The closer to the stereo the better. This effectively limits the length of speaker wire that can act as an antenna.

If the toroids don't eliminate or reduce it to a livable level, you'll need to hit a cb or stereo shop for the remainder of the cures.

A last thought, move the cb antenna away from what you believe is the stereo's antenna. It too, could be the culprit in bringing too much cb signal back to the stereo amplifier.

[Carolina Thunder]

I would bet you money that if he got the radio from a CB shop it was clipped before he walked out the door with it, no matter if he told them to do it or not! The only way the radio would do the things you say is if were over modulating, a stock unmodified radio will not do this especially with an SWR that low. Find a CB shop and have it checked and if it's doing more than 20 watts it's been clipped!