Hey Guys, needing some help with my CB. The problem I am having is what I would call extreme "data" noise. The best way that I can described it is a synthesized rhythmic static toneless bleeping. lol, crazy I know.

It occurs when I put the key in the ignition or when I touch the brake pedal or open one of the doors.

With no key in the ignition, if I touch the brake pedal or open one of the doors, this noise is heard for about 1 minute and then goes away. It starts again if I do either of those actions again. So you can imagine when driving it really sucks.

Just putting the key a quarter of the way into the ignition starts the noise as well.

I can turn the squelch back to about 50% and it does cancel out the noise but this drastically reduces my communications range.

When I remove the coax connector from the rear of the CB the noise is not present.

My setup,

CB - is installed in a overhead Tuffy box. The box and CB are ground to the windshield frame.
Power - cable is routed back to the center roll bar / speakers and then down the roll bar, under the carpet and out the fire wall connected directly to the battery.
Antenna Coax - routed back to the center roll bar / speakers and continues up high on the roll bar to the back, out the tail gate and is connected to a L bracket on tire carrier. A 8 gauge stranded cable is connected from the tire carrier / antenna mount, to the tub of the Jeep.
Antenna - 4' Wilson flex
SWR - 1.5

Any thoughts or suggestions would be greatly appreciated.

Thanks,

 

Only time I have problems with that is when my cell phone is on Edge instead of 3G,

Its a common problem called GSM buzz

 

Even though your SWR is good it sounds to me like you may have a poor ground on your antenna or a poor shielded coax cable. Do you have an ohm meter ? I would check the resistance between your antenna and ground (should be very high, or open), also from your ground point in the antenna and some place in your chassis close to where you connect your ground cable but not to your connection point (resistance should be very low, or shorted).

Also check the resistance between both ground sides on your coax cable and make sure it's very low.

 

It sounds like you have done all of the right things.

Try to keep your coax as far away from any of the Jeep's wiring harnesses as possible or re-route the coax. It could be picking up interference from the sound system's wiring harness or overhead lights.

A higher quality coax with better shielding might be required.

What is the spec on your coax?

 

Mine does this too. I just turn the squelch until it is just gone. Seems OK on trail rides, but you are right, weak signals are blocked.

Hmmm... maybe I'll see what I can do too.

 

Thanks guys for the suggestions,, I have a "to do" list of,,,

Connecting another ground strap from the frame to the tub at the rear
Changing out the coax
Temporarily running the new coax and new power cable exposed outside of the dash and roll bar

I will post the results just as soon as my new coax arrives.

Thanks for the suggestions guys

 

I rather think Noxian has the right of it. Some years ago, I bought a new Nissan Titan. Got in to drive it home, threw my phone on the little tray above the radio. Within minutes I heard noises coming through the speakers. The radio wasn't even on! I thought the truck was wonky, so I turned around and drove it straight into the service bay (I worked at the dealership at the time ). The tech who caught the job shot me a dirty look, picked up my phone, handed it to me and said "Don't put it there."

Behold, he was correct.

Communications radios all share a common trait - sensitive receivers. Car-audio systems do not. (There are various reasons for this which bore most people; suffice it to say it's true.) So if a mobile phone synchronization signal is strong enough to get into the vehicle's electronics, it's bound to get into a communications receiver.

Turn your phone off or goose the squelch. Don't waste time and money on new coax if you haven't already bought it. If you have bought it, install it, because good stuff is always gooder than cheap crap. And small tweaks to improve your antenna system can't hurt much. Just don't go sanding off paint, fer crissake, unless your $75 CB signal is for some stupid reason worth more than your $25000+ Jeep.

That's something I just don't get: Sanding off paint. Let's do that math, shall we? Let's sand off paint to get 1/10 mile more range on my signal or my SWR from 1.4:1 to 1.2:1, so I can go out on the trail, drive my brand new Jeep - WHICH NOW HAS SPOTS OF BARE METAL - through water.

Stupid, stupid, stupid.

I don't care what kind of rust preventative you put on the bare metal - IT ISN'T GOING TO HELP. Eventually there will be rust there. For what? So you can use your CB twice, thrice a month? That's a complete no-brainer.

Especially since RF current doesn't act like AC or DC current. Here's an excerpt from the expert:

That's because RF current doesn't need the same sort of path to ground that electric current requires.

So stop sanding off your paint! You're not helping.

Cheers,

Bob