Problem with amp install

aluminum isn't a efficient ground , just run the ground to the frame might save you some footage on cable and it will be just fine

 

Steel (frame) is heavier and thicker than aluminum so the frame will provide the best ground.

 

Maybe it is , I just never had good luck grounding electronics to aluminum in big trucks moreso rf equipment in 17yrs of installing them in cars, trucks, vans , rvs , big trucks where the worst because of the whole thing be aluminum.

 

Tony,
Question for you, and it's cuz I literally don't know. Are the aluminum cabs or frames (or whatever part of the big trucks are aluminum) bonded electrically somewhere to the vehicle's ground system? The reason I ask is that I know aluminum is a great conductor, or it wouldn't be acceptable by the NEC for structural wiring, right behind copper (with the caveat of having to use a larger size than copper for the same current capacity). If the aluminum shell isn't providing a good ground for electrical gear, might it if there were a big ground bond/braid/bus between the cab/shell/whatever and the electrical system's ground? Or is the aluminum shell being used as a shield for the ECM and the more delicate electronics systems that are supposed to run in the cab, protected from the engine's impulse noises and such?
For the record, I agree with the lads earlier who maintain that power (hot and ground) for radio systems (I'm including amps) should be routed by the shortest path directly to the battery, big fuse right at the battery, and equipment-appropriate fuse right at the equipment.
As I re-read the whole thread, I see that Freightliner Bob is having good luck with aluminum for grounds.
Just a thought: is everyone talking about the *same* grounds, i.e. DC grounds, like the return path to the battery, red to black, fuses and stuff, versus RF grounds, the "other half" of the antenna system, that the coax braid is connected to? Volt mentioned something about the amp having to be mounted at least two feet from the CB or feedback would ensue ??


Normally I'd think it was maybe too late at night and I was missing too much stuff, but it's only 5pm. So either I'm just too old (hey, you kids, get off'a my lawn, or I'll turn my hose on ya!) or I'm....I forgot what I was going to say.
Dang.
Happened again.

 

I'll grant that most trucks have heavier steel in their frames than the aluminum gauge in their cabs, but please note the relative positions of the metals on the attached chart. If you mean it's better to run a large copper wire down the wall of the cab, out a hole and then into the frame, instead of cutting off the copper wire and screwing it into the side of the cab up where the radio is, I'm with you, because the copper is better than the aluminum to get down to the frame.

But I differ with the idea that the steel's weight and thickness make it a better conductor than aluminum for ground (I'm still not sure if this thread is about DC or RF grounds, though). Unless you were trying to pass a couple of thousand amps of DC through one or the other. There's a formula for the cross section of a conductor and current capacity that I can no longer recall, and probably couldn't use anyway

But here's the table of relative conductivities of metals. There's only one higher than copper, and it's easy to imagine why it's not in widespread use for vehicle and house wiring. But look for copper, then aluminum, then steel (both kinds). I thought it was pretty interesting.

Anyway:

 

I'm not saying that aluminum isnt conductive ( I'm no scientist nor argueing with facts) but when it comes to past experience when grounding higher current electronic equipment to the cab of a semi truck 95% of the time I've had issues either engine noise or in efficient power to the unit and almost always was due to the ground being on the cab of the truck , not all trucks just big trucks I don't know why but this has always been the case , and yes I tried it with every install just to try and save time but it almost never worked out is all I'm saying in not trying to give bad advice I'm just sharing my experience is all .

Good luck and god bless .

 

The best place is both lines to the battery.

 

Had the same problem if not the rf or the battery find a good ground for the antenna that should help alot