cb static?

Good grounding and a clean power source that is not near any other powered wires. If all else fails I have a 8 year old cobra Soundtracker series radio that make no noise regardless of power feed. Maybe they still sell them?

 

first find out where the static is comming from .
disconnect the antenna (DO NOT KEY MIC !!) and listen to the radio to see if the static is still there . if it is its comming in through the 12 volt line . if not its comming in through the antenna . then you know what area to work on .

if its the 12 volt lines sometimes re routing the powerlines can help . sometimes a powerline filter can help . if youre plugged into the cigarett lighter plug or other dash/fuse box power feed you may need to run a hot and ground directly to the battery from the radio (and amp if one is used) .

if its the antenna first check coax and mount to make sure their correct . check the swr . sometimes grounding straps can help . sometimes moving an antenna can help .

you can also make a 'rf sniffer" to find the offending component and try to route all power leads and coax as far from it as possible .

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[SIZE=+3]RF Sniffer Sometimes noise generated from within the motor compartment of a tractor or auto can be very difficult to trace down. One of the best ways is with the use of a RF Sniffer. A simple one can be made easily and quickly and is shown below.

CONSTRUCTION:

1. Use an 18' length of either RG/58 or RG/8x stranded center coax. The 18' length should provide enough length to allow reaching all areas needed.
2. On one end, solder a PL-259 connector.
3. On the other end trim back 12" of the outer rubber covering and the shield. This will leave 12" of foam exposed.
4. Trim off 10"of the foam, leaving the center strand exposed.
5. Twist the strands of the wire together to form a tighter wire.
6. Using a broom handle or similar sized round tube, wrap the exposed wire around the handle forming two loops.
7. Tightly twist the excess wire back around the beginning of the wire, to prevent loops from undoing.
8. Remove the broom handle from the windings.
9. Spread apart the loops so that they are not touching each other.
10. Construction of RF Sniffer is now completed.

A more enhanced version that will eliminate most interference or radiation of coax line can be constructed by adding a 5 or 10 watt, 50 ohm resistor in line and soldering the other end to the coax shield as shown below.

USING THE SNIFFER:

1. Connect the end of the coax with the PL-259 connector to the radio.
2. Turn radio on, and the volume up enough to be able to hear the noise when you are outside of vehicle
3. Start and run vehicle engine.
   
4. Move the loop end of the coax around the motor compartment, over motors, etc., being careful not to touch any thing. CAUTION: Be careful around fan motors to avoid fan blades.
5. When the noise level increases, the item that the loop is over is the part causing the noise to be generated.
6. This part may be needed to be filtered, grounded, or shielded ( depending on the part ) to cure the noise problem. Additional information on filters can be found at Special Vehicle Notes
7. Repeat process to locate all the sources of noise.

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My '04 379 created noise from the engine fan solenoid. Fan off = solenoid on, and the buzz was awful. I could hear very well when I was running a good grade and the fan kicked in though.

I tried many things: separate power source, rf chokes, grounds to everything, even changed the solenoid... nothing seemed to help.

The problem seemed to be that the noise generated was being picked up internally in the CB which was bypassing the built-in filters.

I never did fix that problem. Just turned the CB off. And the world got a bit brighter after that.

 

It is not just the Peterbilts that have fan noise in your radio. Have put filters and everything else on my Kenworth and it still comes thru the radio. Changed grounds and powered straight from battery. Nothing changed. Kinda funny how my old cabover from a few years ago gave no noise issues. Probably due to alot of steel on the body.

 

A noise filter on the power supply solved my engine static problem. I have used it on 2 different trucks with Cat engines.