Backwoods Country Girl

So I got a new midland CB an its got terrible electrical interference I cant hear hardly an I cant talk at all. Its all grounded good and I got a 4 ft antenna on my roof. We cant figure out whats the problem any ideas?

89Laredo

did you tune the antenna?

FOXxX

Elabroate - how do you tune the antenna?

89Laredo

depends on what kind of antenna...
If its a steel "whip" you cut small pieces off the bottom until it reaches a 1.5 or less SWR.
Fiberglass may have an adjustment screw that just needs to be turned until proper SWR is reached, or you have to pull pieces of the coil out and cut them until proper SWR is reached.

Caish

goto radio Shack and get a ferrite loop.
http://www.radioshack.com/product/in...ductId=2103222

Its not perfect but it will remove a large portion of line noise.
I've battled line noise lots of times in Semi trucks.
The next option is to build a cage around your ECM, called a faraday cage.
The Cheaper the CB the worse the noise problem, but I've had expensive radios that had issues too.

The choke above will help some.
Put it over your wire and loop your wire through it as many times as you can.

89Laredo

^ X2
might also want to mention that if your antenna isnt tuned, you will end up killing your radio.

Backwoods Country Girl

Its fiberglass an its tuned

Backwoods Country Girl

An I dont just mean on my CB I hear the electrical noise when im tryin to talk to other people on it like the jeep 20ft in front of me on a run they cant hear me they just hear the real loud electrical noise.

Caish

Perfect SWR is 1.1 but in reality 1.5 is good.
I need to know where your radio is mounted and how is the coax ran?
How long is the coax? You want a division of 36, so 18, 9, 4.5 foot.
You do not want the extra coax rolled in a coil shape. That creates a Choke and you loose power.

Double check your grounds and make sure you antenna mount is grounded too.

Turn on your stereo on AM and see if the noise is there too. If it is, its an likely a body ground issue. If not, resource the ground and power lead your using to supply power to the radio.

Backwoods Country Girl

Its 9ft an it aint rolled or coiled anywhere an everything's grounded an it makes the noise radio on off am fm everything.

Caish

Heres something I just thought of.
A bad diode in the alternator will generate a large noise level and since your getting it over the AM/FM and the CB I would suggest you unkhook the wires from the alternator and see if the noise goes away.
If so you got a bad diode (alternator has 3) generating the interference.

Backwoods Country Girl

Explain diode lol

Caish

Alternators actually produce A/C power internally, and diodes are like a one way gate that converts it to DC, then the DC power goes to the Voltage regulator then out the wire to the battery.

Backwoods Country Girl

ok...........an how would you check that

Caish

Easy,
just remove the wires off the alternator and start it up and see if the noise is gone. If it is, replace the alternator, or take it to a shop and have them replace the diodes.