Interference On My c/b ?

[Jeff H]

I had a c/b in my truck before. I pulled it out last year when looking at maybe of getting a different truck. Well now I put it back in. With the key in the acc I have no static. With key in on position but engine off I gain a lot of static as much as 3 on the meter. Now my fan Interfears with it too. My antena is mounted to the side view mirror. Before the antena was behind the cab.

My wire connection is coiled up to the steering shaft gaurd. My ground is mounted near the brake controler. Ive used cheep coax this time. But not sure it would be that. Could use some thoughts on this.

 

[HDH]

Could be the Cheap Coax or it could be the Power for CB is plugged into a "Noisey" Power Circuit, Try moving the Power supply to a different feed.

Also dont have the Coax "coiled up" in a circle, It will act like a RF Choke, Have it layed out in a "S" patern for lower SWR readings.

I hope this helps.

Doug.

 

[swamp rat]

HDH is right on target this time

I get to return the favor HDH. As he mentioned, the cheaper coax could be allowing noise to ingress into the coax. This can be prevented or at least reduced by using better shielded coax. It works wonder on AV gear.



Something else that may likely help, try to get as good a ground with the radio chassis as you possibly can get. Like in the olden days of AM only radios, they had ground straps everywhere to keep engine/distributor whine to a minimum.

 

[TurboSandman]

Jeff;



The ABS controller is sometimes a source of radio frequency interference, especially if power or coax lines run in close proximity to it. My power lines run alongside the hood release cable, through the grommet in the firewall and out along the driver side fender right next to the ABS unit before attaching directly to the battery terminals. I ran heavy guage (8 or 10) inside tinned copper braid with the braid terminating as ground strips to the body at both ends of the run to "ground"any RFI before it got to the radio.



Both my 2-meter and CB radio use this power source with little interference other than the usual ambient static which is present regardless of braking, fan use, etc. You might try attaching directly to the battery to avoid noisy circuits and use some RFI shielding (such as the braid) or avoid the ABS unit entirely.



Let us know how it comes out.



Steve

 

[Jeff H]

One thing I found out is that the mirror on my truck was not grounded. So I ran a wire atatched from the door to the mounting bracket for the antena. Most of the ground wire runs along side of the coax cable. Maybe that ground wire is causing interferance too. All I know is that the last time I had this radio in I had very little interferance at all from the truck.

 

[Alan Reagan]

Look at Fritz's website on TSBs. I believe there is one for a filter on the lift pump (?) that causes static and noise on radios. May be worth your while. One other thing... ... last week I noticed that my reception seemed a little weak. I ran a ground wire from the antenna mount to the frame. Now there is much less noise, reception is better and I'm getting out further.