Outdoor Adventure USA

Ok.. here's whats up I have two different vehicles with CB's both have simular issues. first. both cb's are new vehicle #1 2003 ford f-350 4x4 7.3 diesel. The cb unit is a cobra 29wxnwst. the unit is grounded good and the positive comes dirrectly off the battery. The unit and coaxle are not by any other major electrical components The problems are as follows
1)while driving I can hear a loud buzz matching the rpm's when I let off the pedal it stops. 2) when I turn on the auxiliary trans cooler fan the buzz from it almost blows you out of the truck.

vehicle #2 toyota fj cruiser problems are... 1)if you turn on the wipers you get a very loud buzz 2) if you turn on a blinker you get a click 3) if you push on the brake you get a loud buzz 4) if you are driving along not touching anything every so often you hear the same buzz you get from the brake pedal it last's for 2 seeconds then stops

I' not going to get rid of the units there is nothing wrong with them
please try not to guess what the problem is
please only respond if you have first hand experience or knowledge

Thank You.... Thomas

Sounds like electric noise introduced in either the positive or negative power cables. You should run both cable from any transceiver directly to the battery. Positive AND negative as they are both part of the circuit. You say the negative is gronded well, but I assume to the chassis not the battery.

You can also try ferrite chokes.

the positive is directly to battery on both, but I will have to check on the ground wire as more than likely they are both grounded good but to the chassis. I will let you know if it works. TNX... Thomas

Thomas don't bother to fix the negative grounds you are currently using, just run a direct wire to the battery. If that fixes your problems then you know what the issue is. Good luck. Sounds a lot simpler than what Ollie went through with his connectivity issues.

sdnative wrote:Sounds like electric noise introduced in either the positive or negative power cables. You should run both cable from any transceiver directly to the battery. Positive AND negative as they are both part of the circuit. You say the negative is gronded well, but I assume to the chassis not the battery.

You can also try ferrite chokes.

Eric is absolutely correct. What you have done, by grounding the radios to the chassis, is create an inductive ground that acts as an antenna to any noise introduced by the other vehicle components that make electrical noise (motors, pumps, fans, etc.), and are grounded to the vehicle's chassis (most are). The battery is basically a condenser, and acts as a large isolator from the vehicle's ground.

The radio should have it's power and ground directly wired to the battery, with fuses in each line; both should be of the same gauge as each other, and if the wire is more than 10 feet long, up the gauge on both. While ferrite chokes can sometimes help, usually it's a bad ground issue, either in the radio, or the offending accessory, that lets the "noise" enter the radio circuit...

I have to add that my CB has engine noise (white noise that is changes promotional to engine RPM) coming out the speaker. I have a Uniden 520. None of my ham radios have this issue, so it may just be poorly (or cheaply) designed circuitry inside the radio. All of my radios are connected directly to the battery.

I guess I am saying it may be a problem with the radios themselves.

sdnative wrote:I have to add that my CB has engine noise (white noise that is changes promotional to engine RPM) coming out the speaker. I have a Uniden 520. None of my ham radios have this issue, so it may just be poorly (or cheaply) designed circuitry inside the radio. All of my radios are connected directly to the battery.

This is the culprit with a lot of less expensive electronic devices - poor design, or poor quality components. Ham radios use much more sophisticated circuitry, and deal with more power, in addition to stricter FCC emission regulations (due to higher power output).

Another possibility is a poorly routed or poorly located antenna system. A poor antenna ground, or location that allows it to receive reflected electrical energy from the vehicle, can cause vehicle noise to enter the antenna receiving circuit and cause your symptoms as well...

Good luck...

Cowboy,

I had the exact same problem with the exact same radio in my FJ. There were two culprits. The first was the wiring issue mentioned here. When I went directly to the battery with both positive and negative leads the only sound remaining was the noise heard from the braking system. That two second whine kept driving me nuts even after I had it wired correctly. That was resolved by relocating my antenna. I originally had my antenna mounted on my front bumper. The feedback was due to the coax routed around the engine bay. I finally bought a Bandi mount kept my coax routed away from as many of the electronics as possible and that resolved my issue. Hope this ands all the other posts help...