Sixpack73

Just hooked up a Cobra 19 Ultra (bout the only thing I can find room to mount), and whenever the engine is running or really the lift pump is running, I am getting quite a bit of noise coming through on all channels.

I have installed a power filter (which is connected directly to the battery on both pos. and neg sides) on the radio's power wires, and to my dismay, this didn't solve it.

The antenna is mounted on the driver-side front (via a fender mount that slips just under the hood), and the coax runs through a hole in the firewall.

To isolate this as the issue, I hooked up a separate antenna (diff brand) on the bed of the truck and ran the coax out the drivers door as a troubleshooting test and still had the same problem.

How can I get rid of this nasty interference? Any suggestions other than what I've already tried? Anyone else having the same problems?

hobbz

how big was the filter that you put on it. you may have so much line noise that you need a bigger one

Sixpack73

Not sure how 'big', but here is a link:

link to the filter i used

nineback

If you unhook the coax from the radio does the noise go away? If so the noise is coming in through the antenna and not the power cables. If this is the case then you will probably have to start looking at grounding the various parts of the truck together since the pump or whatever is radiating a signal that is being picked up by the antenna. I am afraid that this is not something that is easy to do but takes trial and error. Initially make sure that your battery cables are tight and the negative ground wires are tight. Make sure your CB is grounded. From there you may have to look at adding grounding strips from the hood to the frame, bed of truck to cab of truck, etc. I don't know where the pump is located and if you can add a grounding wire to it as well. I had a real noise issue with a Ford F-150 and finally gave up. When I installed my ham radio in my 07 CTD I was a happy camper when my noise went away without having to do anything. There are several web sites that deal with this type of noise and give lots of hints but as I mentioned above most are trial and error.

Tom

donnee

When I mounted the radio in my 05, I ran the power wire thru the grommet where the clutch would be and straight to the battery.
I havent noticed any noise other than normal.

Mexstan

Try installing a .005 picofarad across the terminals of the pump. Use the cheap disc kind from Radio Shack or others. Just make sure that it can take a minimum of 15 volts. More is better.

rock crawler

You may also check your ground connection. In the car stereo business we see this all the time. Make sure you are grounding to bare metal, no paint. Also use as short of a ground wire as possible. Something else would be to use a ring terminal to mount the ground wire with and a star washer under it so that it digs into the metal. You may need to use a multi-meter to make sure you are getting a good ground wherever you decide to mount the ground wire.
Also make sure that none of the antenna cables and power/ground wires are running over or next to any power wires for something else, you can pick up noise this way too. Most likely though, the noise is due to a bad ground. If these suggestions do not work you may try installing a ground loop isolator which you can get at any car stereo shop.
Just my $.02