CB Noise

I have a odd problem, with noise in my radio.
First my set up;
Radio.
Uniden Grant XL, about 15 years, old peaked and tuned, never had any issues with it.
Antenna.
102 inch stainless whip, 18 feet of RG8 mini with gold soldered conectors
Truck.
2003 Mack Vission antenna is mounted to the stack bracket with 2 insulated bracket further up up the stack to prevent to much whipping of the mass. (I've used similar mounts on other trucks with no problems)

Now the problem;
I have a lot of static on the radio but if I touch the radio radio or even the microphone it will clear up. I used an ohm meter to make sure there is a good ground between the antenna mount and the chassis of the truck, also between the radio chassis and truck chassis. I made sure the coax wasn't shorted. If I disconnect the antenna wire from the radio, the radio goes completely quiet, so it's not a power supply problem. The next thing I am going to try is a new coax because mine is old and it seems like an interference problem, (thinking a crack in the plastic insulation). The thing I don't understand is why the noise would go away when I hold the Microphone, (the housing is plastic)

 

Ground loop? Is your coax coiled neatly under a seat or something like that? (that's a no-no) Is it a power mike? Try disconnecting that. I don't know, but I suppose a bad amp circuit in the mike could be sending something that's picked up by the antenna.
Just a guess.

 

Its a simple ground issue,if you touch the radio and it gets quite then you need a better ground.
Get some simple 10ga/12ga and acouple of the round terminal connectors. The holes in the connector needs to be at least 5mm so you can use the thumb screw that screws to the actual radio chassis. Connect one end to the radio and the other to something like the visor clip if its mounted above. Just make sure your grounding to metal and not to one of those metal backing tabs between plastics(on the dash)I'm pretty sure most all trucks have cab frame metal behind the visor clips.

Shouldn't take more then 10 min.If you still have noise its most likely going to be how your +/- is connected.
You may need an additional motor to frame ground.
That little grounding jumper usually fixes things.

 

I fixed a problem similar to that one time...I used that 10 ga. wire mentioned above to ground my antenna better (fiberglass truck).

You have to make sure your ground wire isn't too long or your radio will try to use it for an antenna (not good for SWR's).

I ran the wire from the antenna mount down to the top of the door hinge (piano type hinge), connected it to one of the bolts in the door hinge, then ran another wire from the bottom of the door hinge down and out the bottom front of the door and connected it to the frame of the truck.

Cleared my radio right up...the radio was a Galaxy DX 95t, its a somewhat powerful radio that really needs a good heavy duty ground.

 

Tater's probably still right: I started wild guessing because you said you used a meter on it. Another thing is that I like to solder all connections: I hate trusting crimps.
RR: I had that happen to my antenna on a toolbox over my pickup bed. It tried to act as a dipole, but grounded! Switched to a metal toolbox with a short groundstrap and the thing went worldwide on me! Still have that box, ready for new paint.
Funny thing: After a couple years, the ground to the frame was going bad on the webbed strap I used. We looked at it at night with the linear on and it was sparking all along the webbing like a chinese circus!
Anyway, besides soldering wherever possible, it's good to use No-Ox (dialectric electrician's grease) on all connections, especially externals.

 

Grounding an antenna that doesn't require it will cause issues.
The long ground wire isn't very viable,I run both my wires directly to the battery which often times is well over 15',using good quality wire thats well insulated
keeps the interference from other electrical sources from
running skip.
But the addition of a ground strap between the door and the cab is advisable and pretty much standard practice on a new install.Do it going in and its one less rabbit to chase later.

 

I misunderstand or you contradicted yourself Tater. Is not the long ground wire to the battery unviable as well? I know it works, but you'd just said it wouldn't do well.
BTW, the thing that worked for my toolbox was short dual straps, one on each side to ground, the idea being to spread the ground plane out equally on either side of the antenna. Since I've put the antenna on the back of the pickup, (because of plastic new toolboxes), I lost the skip ability it had.

 

yeah I see where I goofed,
It should read something like ......

The long ground wire statement by the other person is what I was referring to as not being a valid(viable) claim.
Ground wires are(can be) pretty much infinite,but having them terminate outside the cab affords less interference from other accessories,power inverters,cell phone hands free sets,refrigerators,HVAC fans as well as the trucks motor.

Some techs will argue this,others that have learned a "better way" have started to wire radio's direct to the batteries,it used to be only amps but many are finding there is a better way.

 

I've always done that with amps too. Stereo equipment has problems as well, picking up unwanted signals in the power lines, so running them on opposing sides of the cab is a trick they use, keeping away from the speaker leads, which emit electromagnetic fields.
I've often wondered why no one has made a wire like a large coax, to use for power, the positive lead would be the inside. I've done it for powering the radio itself, but that's not large enough for an amp. I suppose there are some coaxes big enough out there for the job though.

 

Thanks everyone; the truck is out for some work right now, but I will try a direct ground from the radio thumb screw to the battery when I get it back. I will let you know how I make out.