I'll be as detailed as I can on this and maybe someone can help. I had a uniden PC68XL on facory co-phase antennas in my rig. I upgraded to a 78 Elite. With the SWR meter on the 78, I measured 3:1 or so and the ANT light liked to come all the time. I don't want to walk and talk over everyone, but I do want a respectable setup. I disconnected each side of the antennas and read 2:1 on one and over 3:1 on the other. For the time being I figured I would run the one until I got to a CB shop to help me get set up proper. But with the bum antenna disconnected, I developed a horrible squeal from my stereo speakers when I would key up. So I plugged it back in and all is well.
I made it to a CB shop and now have the radio peaked and tuned, and a new single Stryker antenna and coax setup with an SWR at 1.2-1.3 on all channels acorrding to his meter (not mine, but still low). Radio gets out much better now, but still have the sqeual. The only way to get rid of it is to turn the stereo volume to 0 or off. Doesn't matter if I'm listening to radio, or CD, I still get the squeal. The CB shop suggested replacing the stereo antenna wire. It's a company truck so I don't like that option. Some other people suggested adding a ground wire to the stereo chassis. I did that but no luck. Any other idea's?
Just for grins, I got out my multimeter and found continuity between the coax of the stereo and the CB chassis, and various other locations. I would have thought you would want them isolatd, but I'm new to all this and may be mistaken.
Lets hear it for squeals
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Phaze91460
All grounds are grounded eventualy through the battery - post. so you will have continuity through those points.
As for the squeel. We dont have all the information yet so help me out. Are you using a power mic ? What about radio checks, are you transmitting clear or is there a squeel going out to other radios ? Is the squeel only in your cab on the stereo speakers ? Does your radio have talk back and are you using it .... as in when you get the squeel, is it on.
As for the squeel. We dont have all the information yet so help me out. Are you using a power mic ? What about radio checks, are you transmitting clear or is there a squeel going out to other radios ? Is the squeel only in your cab on the stereo speakers ? Does your radio have talk back and are you using it .... as in when you get the squeel, is it on.
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darkhorse
Using factory uniden mic- Pistol grip with chrome grill.
I transmit and recieve with no problems with the stereo volume at 0 or off. Squeal doesn't change volume with the stereo, it's always ear piercing loud. As such, I wouldn't even dare try to transmit with the stereo volume up any. if it didn't transmit the squeal directly, it would surely pick it up in the mic and transmit that way.
it's only on my stereo speakers. And it's on all of them
no talkback on the CB. And now that you mention it, I do get a talkback effect with the stereo on and volume at 0. It isn't loud, but I can hear myself through the stereo speakers.
I forgot to mention earlier, I can turn the mic gain down and help get rid of the squeal. But I have to cut it in half or better to do so. And if it helps any, it's an '06 Frieghtliner Classic
I transmit and recieve with no problems with the stereo volume at 0 or off. Squeal doesn't change volume with the stereo, it's always ear piercing loud. As such, I wouldn't even dare try to transmit with the stereo volume up any. if it didn't transmit the squeal directly, it would surely pick it up in the mic and transmit that way.
it's only on my stereo speakers. And it's on all of them
no talkback on the CB. And now that you mention it, I do get a talkback effect with the stereo on and volume at 0. It isn't loud, but I can hear myself through the stereo speakers.
I forgot to mention earlier, I can turn the mic gain down and help get rid of the squeal. But I have to cut it in half or better to do so. And if it helps any, it's an '06 Frieghtliner Classic
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darkhorse
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darkhorse
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darkhorse
I don't know if I want to rip everything out, or just my hair. lol
I tried regrounding the stereo and then the CB through a metal plate in the cab that I knew was grounded, but not at the same time. I know, not the best place, but I can't hide a wire going all the way to the batteries. Didn't work. I checked and all of my coax connections on both antennas are tight. I finally dug into the connection to the stereo antenna. There are no shorts in it, and I have continuity on the center pins. While I had it unpluged from the stereo I keyed up and didn't get the squeal, but it was still picking up like a talk back through the stereo speakers. So I think I may have ruled the stereo coax and antenna out. I'm glad, because I wasn't looking forward to trying the CB antenna on the passenger side. I had also tried my old CB and mic on the new single antenna, and still had a squeal.
But that leaves me with 2 options. Either the stereo speaker wires are somehow shorted and picking up the signal, or it's something feeding through the power wires. But I haven't had any issues with my stereo speakers cutting out, and I don't know if noise in the power wires could even be transfered to the audio output. And I'm still confused that it only happens with one CB antenna (either single setup, or factory co-phase with one disconnected). Yet with both factory antennas, it didn't happen.
I thought I found a CB shop to have look at it, but they are closed today. Shoot.
I tried regrounding the stereo and then the CB through a metal plate in the cab that I knew was grounded, but not at the same time. I know, not the best place, but I can't hide a wire going all the way to the batteries. Didn't work. I checked and all of my coax connections on both antennas are tight. I finally dug into the connection to the stereo antenna. There are no shorts in it, and I have continuity on the center pins. While I had it unpluged from the stereo I keyed up and didn't get the squeal, but it was still picking up like a talk back through the stereo speakers. So I think I may have ruled the stereo coax and antenna out. I'm glad, because I wasn't looking forward to trying the CB antenna on the passenger side. I had also tried my old CB and mic on the new single antenna, and still had a squeal.
But that leaves me with 2 options. Either the stereo speaker wires are somehow shorted and picking up the signal, or it's something feeding through the power wires. But I haven't had any issues with my stereo speakers cutting out, and I don't know if noise in the power wires could even be transfered to the audio output. And I'm still confused that it only happens with one CB antenna (either single setup, or factory co-phase with one disconnected). Yet with both factory antennas, it didn't happen.
I thought I found a CB shop to have look at it, but they are closed today. Shoot.
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Phaze91460
I dont know where to direct you anymore on this. I know I can key up and talk on my living room surround from my drive way. I think the radio I have ( Connex 4600 ) is shooting a little more power than what you have and I have one power amp for the main stereo speakers in my truck and one amp for the subs but no talkback or feedback or squeel. Maybee you could pm mike ( AKA MR Radio Active ) and see if he had any more sugestions on this.
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darkhorse
Thanks phaze, I'll keep Mr. RA in mind. I did at least figure out part of the problem. I got to talking with another trucker and we were trying to figure it out. I offhanded mentioned to him this was not the factory stereo, and also that someone else had put a different one in before me and then reverted to factory when they turned the truck in. We got to talking and I mentioned the poor splice the last driver did when he re-connected the factory wiring. Instead of using each end of the butt connector to splice the wires together, he inserted each wire pair in to the same end of the connector and crimped. It looked somthing similar to a pig tail. The other driver wondered if maybe leaving the other end of the connector open and uninsulated is where the interference was getting introduced. We went in and re connected all of the wires and it got rid of most of the squeal. We thought we had it all and wasn't squealing until I went to put the stereo back in the dash.
As soon as the body of the stereo came in contact with the metal sleeve in the dash, the squeal came back, but at least not as loud. The dash panel that the stereo goes in is metal with a wood veneer type finish. So I put some electrical tape around the edge of the opening and reinserted the sleeve, and then the radio. That helped some more. I also was getting a little static when my sub-out RCA's would rub the sleeve, so I covered them too in electrical tape. Essentially, I tried to isolate anything that didn't need a direct ground. I got rid of most of the squeal now. It only comes when I have the mic gain above 3/4 and even then it's hit and miss. But the radio is peaked and tuned, so I was able to cut back and still get out good.
Now, the only problem I have is the talkback effect on my stereo speakers. Even with the mic gain down, if the volume is not at 0 or off, I still get a very static sounding talk back effect, albeit not near as loud as the squeal. I talked back and forth over the CB with the other driver to see if I was broadcasting poorly too. He said I was comming in loud and clear and not hearing any background noise or the staic talk back. When I would adjust the mic gain to max and start to squeal on my end, he could hear it picked up from the mic, but not a direct broadcast of the squeal.
So I guess until I have more time I can live with it. At least now I can key up without blowing my ear drums or other drivers knowing I have a bum setup. Most people seem to need more grounding for their problems. I seem to need less. I thought of a ground loop isolator for the stereo, but not enough room in the dash. I think I may have to go through and isolate any interference one by one. Any one think maybe try to isolate the CB somehow? If so, would I install something on the coax, the power wires, or both?
As soon as the body of the stereo came in contact with the metal sleeve in the dash, the squeal came back, but at least not as loud. The dash panel that the stereo goes in is metal with a wood veneer type finish. So I put some electrical tape around the edge of the opening and reinserted the sleeve, and then the radio. That helped some more. I also was getting a little static when my sub-out RCA's would rub the sleeve, so I covered them too in electrical tape. Essentially, I tried to isolate anything that didn't need a direct ground. I got rid of most of the squeal now. It only comes when I have the mic gain above 3/4 and even then it's hit and miss. But the radio is peaked and tuned, so I was able to cut back and still get out good.
Now, the only problem I have is the talkback effect on my stereo speakers. Even with the mic gain down, if the volume is not at 0 or off, I still get a very static sounding talk back effect, albeit not near as loud as the squeal. I talked back and forth over the CB with the other driver to see if I was broadcasting poorly too. He said I was comming in loud and clear and not hearing any background noise or the staic talk back. When I would adjust the mic gain to max and start to squeal on my end, he could hear it picked up from the mic, but not a direct broadcast of the squeal.
So I guess until I have more time I can live with it. At least now I can key up without blowing my ear drums or other drivers knowing I have a bum setup. Most people seem to need more grounding for their problems. I seem to need less. I thought of a ground loop isolator for the stereo, but not enough room in the dash. I think I may have to go through and isolate any interference one by one. Any one think maybe try to isolate the CB somehow? If so, would I install something on the coax, the power wires, or both?
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darkhorse
YAY!!!! FINALLY FIXED THE DARN THING!!!!
Well, I know what I need to do anyway. I asked a CB shop about my now talkback effect on a whim because I'm shut down for a while. He said that it was a grounding issue, but not something that could easily be fixed by moving grounding points (like other shops had suggested). He recommended running a ground wire from the chassis of the CB to the chassis of the stereo to ensure they are getting matched grounds. If I understand him right, if the voltages on the grounds are off even by a fraction, then the RF signal from the CB can ride the ground wires and feed in to the stereo. I know I'm not expaining it as good as he did, but I'll be a monkeys uncle, the darn thing worked. I did a quick and dirty connection with my testing wire and it eliminated the talkback. Now the only problem is making a permenant connection that I can hide from the conpany's mechanics, or a hidden quick connect to remove it before I go to a terminal. Either way, I need to be able to run it behind the dash with no visible holes or cuts. Being a company driver does have its drawbacks.
For anyone wondering where this guy is, he is at the TA Truckstop in Green Castle, PA. I-81 EX 5. He's the only one I've been to that had a suggestion that helped any and will likely see more of my business. All of the others just kept saying to move the ground wires, which didn't do squat. Although I did have one that let me try a power filter on the CB for free that made it slightly better but not enough to buy it.
Well, I know what I need to do anyway. I asked a CB shop about my now talkback effect on a whim because I'm shut down for a while. He said that it was a grounding issue, but not something that could easily be fixed by moving grounding points (like other shops had suggested). He recommended running a ground wire from the chassis of the CB to the chassis of the stereo to ensure they are getting matched grounds. If I understand him right, if the voltages on the grounds are off even by a fraction, then the RF signal from the CB can ride the ground wires and feed in to the stereo. I know I'm not expaining it as good as he did, but I'll be a monkeys uncle, the darn thing worked. I did a quick and dirty connection with my testing wire and it eliminated the talkback. Now the only problem is making a permenant connection that I can hide from the conpany's mechanics, or a hidden quick connect to remove it before I go to a terminal. Either way, I need to be able to run it behind the dash with no visible holes or cuts. Being a company driver does have its drawbacks.
For anyone wondering where this guy is, he is at the TA Truckstop in Green Castle, PA. I-81 EX 5. He's the only one I've been to that had a suggestion that helped any and will likely see more of my business. All of the others just kept saying to move the ground wires, which didn't do squat. Although I did have one that let me try a power filter on the CB for free that made it slightly better but not enough to buy it.
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-TIMSTER-
Interesting... I've the same issue in my Pete! With radio on mute or zero volume, I key up and BAM goes the squeal. It's an Alpine aftermarket stereo. I"ll have to try this ground ideadarkhorse wrote:YAY!!!! FINALLY FIXED THE DARN THING!!!!
He recommended running a ground wire from the chassis of the CB to the chassis of the stereo to ensure they are getting matched grounds. .
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Big Guns
Lets hear it for squeals
Very good post and good trouble shooting info. Like Phaze if I key up sitting in my drive way, the family can hear me over the TV's. In the car if I have the radio on (factory) I get the talk back through my speakers, but If the radio is off, no talkback. I'll have to try that grounding Idea myself. Once again great post and good info.
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darkhorse
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Rex_foxhound
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-TIMSTER-
RG-59 for co-phase not RG-8X
Darkhorse, I figured it out. I simply disconnected the right side antenna from the co-phase jumper and that took care of the squeal when I key up. I no longer have any squeal and no feedback what so ever. The ground is bad on the passenger side antenna so I just won't use it.
Also, please note: RG-59 is recommended in co-phase dual antenna setups in commercial Class 8 trucks instead of RG-8X. RG-59 is used for dual antenna installations only. The RF resistance of this type of coax is 72-ohms. Within this group you will find coax labeled with RG-59 or RG-59/U. These cables have a solid center conductor. The second type is RG-59A/U and they have a center conductor made up of many thin wire strands (normally about 19) that are twisted together to form the center conductor. The common outer diameter for this type of cable is about 0.22".
Also, please note: RG-59 is recommended in co-phase dual antenna setups in commercial Class 8 trucks instead of RG-8X. RG-59 is used for dual antenna installations only. The RF resistance of this type of coax is 72-ohms. Within this group you will find coax labeled with RG-59 or RG-59/U. These cables have a solid center conductor. The second type is RG-59A/U and they have a center conductor made up of many thin wire strands (normally about 19) that are twisted together to form the center conductor. The common outer diameter for this type of cable is about 0.22".
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darkhorse
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-TIMSTER-
Yup, true. Either way, we've eliminated a definite nuisance. :Peace!:darkhorse wrote:Timster: Sounds like you had the complete opposite problem I did. My squeals popped up after I went to a single antenna and when the stereo was at something other than 0 volume.Glad to hear you got it fixed though.
