Help with RF Noise

[wilson04]

I have alot of RF noise coming though the antenna of my semi. Here is my set up. I have a 99 KW W900L, 3406E Cat engine, Dx99V radio, Wilson 2000 antenna (SWR 1.3 on 1 & 40).

Things I have gounded...

Engine to frame.. both sides with 2ga. braided strap... 0.3 ohms
Antenna to cab.. has good gound to cab... 0.3 ohms
Cab to frame... (1) 2ga. braided strap... 0.3 ohms
Radio to cab... 12 ga. wire 20in long (shortest rte. to gnd)... 0.3 ohms
Power & GND.. 8ga wire to batt both PWR & GND.

The radio has a S meter of .5 when truck is off. Channel 19
The radio has a S meter of 4-6 when truck is on. Channel 19

When I Switch bands from HI to LO while truck is on the S drops to .5. It seems the truck just has noise on the 40ch on CB band. The farther I tune away the quiter it gets.

Do those ferrite chokes work from Radio Shack?
How bout those .01 caps?

What else can I do? Do I have any other options?

 

[Robb]

The noise is going to frop down when changing bands due to the antenna's lack of efficiency on that band - since it is a tuned length for 11 meter/CB - right?
THe residual noise has to do with location and enviorment. I get 1-3 S-units on my base station - on average. But if I get in my mobile and drive off away from the city - it drops to nil.

 

[wilson04]

I changed out my alternator on the truck and it cleared everything up. Now my S Meter rides on ZERO. (most of the time)