bobcotkg Posted May 8, 2012 Share Posted May 8, 2012 My Superliner has over the years has come to let the CB talk over the AM FM radio. If you turn up the dynamike to get out, it squeals like mad, thru the AM FM speakers. The cab is grounded good. All new coax to the CB antenna. It does it with the "big radio" or my stock Cobra 29. It has gotten worse the past couple months. Wondering if anybody else has ran across this problem? It has been quite a pain in the ass messing around and have gotten nowhere.Bob Quote Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/ Share on other sites More sharing options...
Green Dash Posted May 8, 2012 Share Posted May 8, 2012 I had this problem once in a Freightliner but I was slip-seating at the time, so the solution was to drive another truck.With that not being an option, every situation like yours that I've heard of was a result of grounding or cable routing issues. The cb antenna may need to be grounded to the frame. Also, if the cb coax is routed along side the speaker wire, bleeding could result.There are probably other causes of this, but those are 2 that I remember being told were common. Quote Jim Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118305 Share on other sites More sharing options...
bobcotkg Posted May 9, 2012 Author Share Posted May 9, 2012 Thanks,The way I understand it is that the outside part of the coax is the ground. I know quite a few CB guys say the antenna must be grounde and what not, but Dad has an antenna that is not grounded on a pickup and it works very well.Did some quizing of a couple friends today and they seem to think it has to do with the AMFM antenna being on the roof and cophasing, and the stronger one takes over..In reality there seems there is more to CBs than just hooking up wires and tuning the antenna...Bob Quote Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118391 Share on other sites More sharing options...
theakerstwo Posted May 9, 2012 Share Posted May 9, 2012 Just for the fun of it disconnect the speakers and connect back backwards from what they were. Seems like back in the old cb days ther4e was a driver here had same thing.I am talking about am/fm speakers. glenn Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118394 Share on other sites More sharing options...
Green Dash Posted May 9, 2012 Share Posted May 9, 2012 Correction: I mistakenly said the antenna had to be grounded, but it's the MOUNT that needs to be grounded and not all vehicles require a seperate ground wire. I had a Wilson 2000 antenna mounted on the mirror arm of 3 R models I drove and all worked fine. Tried the same thing on a CH with similar mirrors and couldn't get a good ground. I then mounted it on the grab handle above the rear window and that solved the problem. I drive a Sterling now and when I asked my CB guy the best place to mount the antenna (got them newfangled mirrors) he said "on a different truck". I have it on the handle above the window with a wire running down to the exhaust bracket. Quote Jim Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118426 Share on other sites More sharing options...
41chevy Posted May 12, 2012 Share Posted May 12, 2012 Try a CB RADIO LOW PASS FILTER. Radio shack and other type stores carry them for about $15.00. It's a small unit you plug in between your cb radio and the antenna that reduces interference to nearby electrical devices. A low pass filter filters out signals that you do not want transmitted from your station. CB Radio is on 27 Mhz. Most Low Pass Filters filter out all signals above 50 Mhz. Cb Radio filters are used to combat RFIor Radio Frequency Interference, which is what you appear to have. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118789 Share on other sites More sharing options...
bubbamobilin Posted May 12, 2012 Share Posted May 12, 2012 I just experienced the same problem. I had to change AM/FM tuner a few weeks ago. The old one was 12 years old and finally just gave up. Ever since I installed the new tuner my CB bleeds through on the speakers and I cannot pick up any AM/FM stations but the Sirius satelite part works fine. If I hit the mute button on the radio before I talk on the CB it does not bleed through. I have not been able to correct my problems either. Quote Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118798 Share on other sites More sharing options...
Lmackattack Posted May 12, 2012 Share Posted May 12, 2012 Does the same for me...just turn the volume down. Quote Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118822 Share on other sites More sharing options...
Rob Posted May 12, 2012 Share Posted May 12, 2012 Try a CB RADIO LOW PASS FILTER. Radio shack and other type stores carry them for about $15.00. It's a small unit you plug in between your cb radio and the antenna that reduces interference to nearby electrical devices. A low pass filter filters out signals that you do not want transmitted from your station. CB Radio is on 27 Mhz. Most Low Pass Filters filter out all signals above 50 Mhz. Cb Radio filters are used to combat RFIor Radio Frequency Interference, which is what you appear to have. PaulA band pass filter is actually a little better than a low pass but a bit more money. I'd look for a band pass that will pass anything from 25-30Mhz and reject all other frequencies outside of this envelope. This will allow for slight mistuning that is prevelant in production radios of the consumer electronics design.Rob 1 Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118834 Share on other sites More sharing options...
41chevy Posted May 12, 2012 Share Posted May 12, 2012 A band pass filter is actually a little better than a low pass but a bit more money. I'd look for a band pass that will pass anything from 25-30Mhz and reject all other frequencies outside of this envelope. This will allow for slight mistuning that is prevelant in production radios of the consumer electronics design.RobGood point! I for got about the bpf. With the digital AM /FM radios it's generally a narrow band interference. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment https://www.bigmacktrucks.com/topic/24984-cb-radio/#findComment-118869 Share on other sites More sharing options...
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