My question is would a NMO permanent mount reduce the interference further being it’s better grounded? On that note moving the negative from the battery post to the chassis ground also helped a little. Any feedback is much appreciated!
Getting the negative power wire off the battery did you more good than you think.
While it helped your noise issue a bit, it also prevented an issue that is specifically mentioned in the trucks owners manual. Modern vehicles, like you truck, monitor the current consumption on the 12 volt system. It does that with a Hall Effect sensor that is on the cable that runs from the battery negative terminal to the chassis.
When you run a radio directly to the negative terminal like that, it bypasses that sensor and can create issues for you. While likely not big issues, it was important enough that they put it in the owners manual on earlier model trucks.
The noise from the LED lights and other electronics can get into the radio two ways:
Through the power feed
Through the antenna/coax.
Here's what I'd recommend:
- Take the negative lead from the radio and ground it close to the radio. Like within a foot or two. Make sure it's good body metal, scrape the paint back so you are on bare metal. Use a self tapping screw or a nut/bolt to make sure you have a good connection. Depending on where the radio is mounted, you may find a local grounding point. They are usually under the dash, under the seats, maybe under the center console. Those are usually 6mm x 1 studs and you can get a suitable nut/washer from a hardware store.
Keeping that ground wire short gives a good path to ground for any noise, and keeps the long wire from acting like an antenna.
- Make sure your positive power lead is run away from existing wiring harnesses. Try not to bundle the positive wire with other vehicle wiring harnesses.
-If your radio chassis is not grounded directly to the body, try that. Yes, the negative power lead will be attached to the radio chassis and eventually to your ground point. I've had vehicles with odd issues that were solved by running a ground strap from the radio chassis/bracket mounting bolt straight to body ground with a short strap. This is important if you'd mounted the radio in a way that the chassis/mounting bracket is not grounded to the truck body.
- Since the magnet mount is not really grounded to the body, the coax can pick up and/or radiate RF. Since it has to travel all the way back to the radio to find ground, that's probably not helping things.
Doing a proper NMO mount on the truck roof might help. At minimum, it'll improve performance slightly by having an actual ground connection at the antenna base, and will put the antenna right on the ground plane.
Which one of those is going to fix it? Might be one, might be several, you'll have to try them to find out. Doing all of those will remove all doubt about your installation, and help it perform as well as it can. It really is worth the time/effort to do that. I've never once regretted taking the extra time to do a permanent mount antenna and to properly run all the wiring.
