Help with engine noise through CB!

[AlKoholic]

I'm getting a ton of engine noise through the CB.

Here is my setup, Arizona rocky road antenna holder, uses bolts that attach tire carrier to body. 3' firestick, cobra cb. Grounded to chassis and power direct to battery.

Has to be ignition, alternator, fuel pump, etc. because only happens when engine is on, rest of time it's clear. What do you guys think, should I get a filter and see if it helps? Or what should i do?

Thanks,
Matt

[Pondfly]

Run the antenna cable as far away from power cables as possible.

[AlKoholic]

My cobra cb manual specifically says to run the power wire directly to the battery. So why would it tell me that, if it wasn't a clean source of power? I agree that maybe power from inside might be cleaner, but then won't I have problems with radio interference, wiper motor interference or whatever other power choice I decide? I was thinking maybe the cigarette lighter since I don't use it anyway, and their is an additional 12 volt source now anyway if I did need it.

I also just tried running the ground right to the battery and it still has a ton of noise no difference.

Thanks for the input so far guys, just trying to figure this out.

Thanks,
Matt

[Donny 01 TJ]

go to radio shack and get one of these they run 14.99 and work well http://www.radioshack.com/images/ProductCatalog/ProductImage/270/t270-051.jpg
Use this 10-Amp Heavy-Duty Noise Filter to reduce interference in your high-power automotive entertainment and communications equipment such as car ...

[b1pig]

Electrically and RF speaking, the interior of a motorvehicle is a violent arena.

You can get noise from placing the ground wire in the wrong place. Sometimes moving the ground wire to a new location helps. Differences in length of the power cables can also contribute to engine noise. Depends on how sensitive your radio is. Another issue you may have. If the power wire is routed to the battery, it could be picking up interferance from the engine compartment. Since the cable is connected directly to the battery, and so is the alternator... instant "whine" from the alternator.

I would suggest that the power be pulled from an accessory out from the fuse box if available. I have ran CBs like this for years and never had a problem with noise. Besides that, a CB only transmits at 4watts. It's not like you're popping 100watts at 22amps draw like my HAM does in HF. That one HAS to be a direct connection.

If your problems continue, you may be able to solve it with a "open" magnetic choke that you wrap the power wire around, or a wired filter that is spliced in to your power wire.

Also, as Pondfly stated... ensure that the antenna cable is routed as far away from any power wires.

[Jhonyquest97]

does it get higher when te engine is reved. if yes don't bother with the filter they usually don't work. just do what the above said.

reground it somewhere nice and clean... sometimes if the metal is impure you don't get as well of a connection.

I work at a carstereo shop and we like to run the power wires on one side of the car and the ground on the other with any other wires (like rca's but i don't think u have them) Anything that transmits a signl to sound can pick up interference.

[Scrambler82]

:cool:

If I repeat forget I posted...

With the engine running, take the antenna wire off from the rear of the radio, if you still get noise then it is coming to the radio by the power wires, if not then it is coming in through the antenna.

If you still get noise after removing the antenna connector then you need a clean power source, the battery !
I know you wired from the battery but did you twist the wires approximately 10 turn per foot, did you put some braid over both wire and ground one end of the braid at the battery end, but not to the battery. Also, as stated grounds are important and finicky (sp), ground everything to the frame, the chassis of the radio and the antenna mount. Run your wire away from thing that create noise, i.e. fan motors, wipers, computers, etc.
You can use a line filter but try the other stuff first and see or start with the line filter and see which way to go.

Noise in the system is hard to trace and eliminate.
Take your time and don't get discouraged if the first thing you do doesn't help.
If you add a fix to the radio system / electrical feed and it doesn't work the way you think it should, leave it everything help.

Luck,

[JoeyTiles]

CHECK YOUR GROUND...Make sure you have a good ground and make the ground wire as short as possible. That should fix you problem.

[Scrambler82]

:cool:

AlKoholic,

How's the noisey CB doing ?