Cb radio break noise

Okay so I have been trying to figure out my cb radio catches my 3 turning on and my break being pressed. I have switched the ground around to good areas, still noise. I even ran the leads strait to the battery still got the noise. My friend for some reason cut my coax cable witch I repaired and isolated to keep signals out. I even rerouted that. I still getting the noise....has anyone had this problem that can help?

How did you repair the cut? Any pics of the repair? And when you say it's "catching" stuff, what noise are you picking up? Chirping? Squealing? Humming?

If there is even a small break in the shielding of the coax still it will pick up (and emit) noise.

I had the same noise with the Brake booster motor in my HF install. I have got it pretty much eliminated. Here are the things I did.
(A) Power B+ is ran straight to battery with a choke at the battery.
(B) A ferrite at the coax connector of the Radio. (Make sure the coax braid is bonded to the vehicle ground at the antenna point and is bonded good at the PL259 at the Radio. If not it will completely kill your transmit power. This does not work on a magnet mount antenna.)
(C) To eliminate RF Noise, it is extremely important that the Radio be "RF" grounded as close to the Radio case and vehicle frame as possible. Run a #12 wire or heavier from the case of the radio to a good ground point. The shorter the better.
Attached is a pic of the choke ferrites on the power leads of the Radio and the heavy black ground wire from the case to the seat track bolt.

My IC-706 has a remote mount head. I also have a ferrite at the remote head connection at the front of the Radio.
All this has just about eliminated any noise from getting in the Radio.

The brake booster is electric and puts off a lot of noise. Keep the lines away from the brake booster. Are you running the coax near powered lines or harnesses? If you do, try and cross them at 90 degrees vs. running parallel to them.

RadioMike has especially good recommendations above.

Where is your antenna mounted?

I hook clamped the center wire then soldered it the electrical tape. The I connected the copper sheild. Put foil on it. Then I electrical taped that. I have moved it away from the brake booster, still same noise no wires are crossed or any of that. And when I start the truck I get a humm. But when I step on the brake it sounds like a TV cowboy yelling "woooo" through it

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And the cb antenna is mounted on the air hood cowl

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I didn't take pictures but this is the instructions I followed to do the repair.
http://howtocbradio.com/how-to-fix-cb-coax-cable

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Good morning ......... don't want to sound negative. Not sure what the air hood cowl is. If it is either of the air inlet pods at the back of the hood, these are fiberglass. Just make sure you are getting a good ground to the body at the antenna point with your shield.
Your link to the coax splice is scary. Coax needs to be a specific ohm impedance to work correctly. 50 ohm (RG58) for CB Radio. 75 ohm (RG59) for TV. That splice can't be to any spec. I would replace the whole run of coax.

Yeah, that is definitely not the correct way to splice coax. The problem with using the aluminum tape is that the adhesive is non-conductive (unless you buy tape that specifically has conductive adhesive, even then it's not a good idea) so there isn't any way for the tape to actually become part of the shielding. It'd be like trying to patch a water hose using electrical tape. Sure, it might look like it'll work, right up until you turn on the water and let it build pressure, then it will just leak right past the tape. And in this case it's like there is water on both the inside and outside of the hose, so it can get in and out.

And as RadioMike said, it's unlikely that the splice will actually match the impedance of the original coax, which does make a difference in your ability to send out and receive signals. The drastic reduction in distance and isolation between the center conductor and the shielding is also a real problem, as it could effectively create a "short" at radio frequencies, since RF voltages don't behave the same way a DC voltage applied to the cable would. This could also be what is causing the noise leakage into the coax.

If you really have to splice the cable back together, then you need something like this (but rated for the correct impedance): http://www.homedepot.com/p/Tyco-Electronics-Gel-Coax-Splice-Kit-1-Clam-CPGI-569224-1-K/202204333

Notice how you're putting connectors on the cable ends and using a male-male connector to hook them back together. This ensures the shielding and insulation is consistent the whole way around the center conductor. Even having a small nick in the shielding is enough to let noise in/out dependinbg on the frequency and signal strength.


Really though, like RadioMike said, you're better off just getting a new cable and replacing the whole run. I'd make your friend pay for it and then use the old cable as a whip to teach him to never cut cables/wires all willy-nilly.


This is a problem I have with the CB radio crowd, far too many of them have absolutely no idea what they are doing, or how any of it even works, so you end up with things like that terrible splicing example, or modified radios that transmit out of band, over power limits, and with splatter and noise for everyone within 5 harmonics. The worst part is a lot of these people just don't seem to give a dang about it. Such a stereotypical "manly man" trucker mentality. "My way or the highway bud, I've been doing it this way for years and it's never been a problem for me so screw you."

Thank you H3Wolf for being willing to admit you don't know something and actually ask for help from people who do know what they are talking about. If more people were like that you wouldn't see stuff like that "splicing" page.

Thank you. I appreciate all the advice. Yea I'm pissed at my friend, we'll ex friend he messed my install because I didn't have a drill bit to acomadate the cable end so he cut it.... needless to say I'll be doing those things on my own now. I tried to get him to pay for but unfortunately he got station somewhere else, and now he wont. I'll get a new cable and antenna and cable, and mount it, and ground it Same spot or just leave the old one for one of my other things I want to do. I'm moderate with working with wires but not with coax. That's why I asked for help. Like I said thank you for the advice. Now recommendations for new stuff and where to mount it? I have a cobra 19 ultra III cb what should I use for cable and an antenna?

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The two most popular locations are a spare tire mount or a mount on the drivers side fender that looks kinds like a match to the AM-FM on the other fender. Both will take a 3/8 threaded whip. Advice on an antenna is that a 1/4 wave antenna is 102" long and is the best for mobile. In most cases that is not practical and most mounts will not hold up to the stress that long of antenna will put on them. You can get antennas that will fit either mount that are 3' - 4' - 5' and 6' long. All of these will have some sort of loading coil to make up the electrical frequency at 27mhz. I would get a antenna with a center or top loading coil. My favorite is the Hustler HQ-27. It is a near top loaded coil with an overall length of 56". A spare tire mounted antenna gets the antenna up high and no holes to drill. The cable passes through an existing vent opening. My cable of choice is RG-58A/U. It has a stranded center conductor. Attached are some pics for thought.

Personally I am going to go with a roof mount, but since I park in my garage I need to be able to fold the antennas down (actually, it doesn't matter where I install them, the garage opening is too short to allow a fixed mounting no matter where I put them). I've come up with a rough design of a fold over mount that will clamp onto the roof rails, but I need to finish drafting out the design. I'm going to build them from aluminum angle. I was hoping to have them all done before my trip tomorrow, but the first iteration using steel angle turned out poorly since I didn't do a draft of the design first, I kinda of figured it out as I went. Hopefully I can fabricate them sometime next week and finally get my radios installed. I'll be posting everything in my build thread once I am finished.

So where can I get a spare tire mount for the antenna?

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I got mine at an off-road store . They called it something like a dune flag mount . You can make one out of a flat piece of metal by bending a 90 at the top and drilling 2 holes .

Yea I'll probably do that. Unfortunately finding things out in KS is kinda hard since I don't know the area very well

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I previously used this mount, minus the back bracket. http://www.amazon.com/Firestik-Plat...pebp=1435271663540&perid=1YHGV5XBNGR9T40CFCG4

Try here: http://rocdoc.net/

This guy has a specific mount for the H3 rear door. Go the $20 to get Stainless so you will get a good ground.

Thank you that looks like it works great. I'll get that

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Be ready to run a separate wire with a terminal ring at each end from your stud down to the frame! Ground that sucker!!

So I'm going to try and ground the cb itself (box) see if that helps, cause I replaced the coax and the antenna got rid of the break noise, now I get alot of static until I touch the cb

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Sounds like you have about got it. Yes, grounding the Radio case will help. Keep the wire as short as possible. Also use a fairly large gauge wire for the ground. If it will be a long ground strap, say up to 8", you may want to use a ground braid wire. It sounds overkill but RF noise travels on the surface of a wire. So, the more outside surface or circumference you have, the better.
Another area that noise gets into a Radio is the power leads. This is where you need a Ferrite bead made from a mix 31 or 43 material. Attached is a pic of mine. You can get these off Ebay. Just make sure of the mix.

Thank you

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