I just installed this setup on the back of the cab. Picked up a 4' Francis antenna. 18' of thicker coax and a mirror mount. I was getting nothing but static on the factory wiring on the new Mack. I appreciate you giving the best setup you've experienced. I'll know more tonight when I get a chance to run with it but actually being able to hear people is a good start lol. One nice thing about the Macks is a very quick install and the coax is easily tucked in under the passenger door weather stripping.Unfortunately it’s probably going to require some out of pocket expense but that’s the only option when the factory setup isn’t functioning properly, and it’s money well spent. I would first replace the factory antenna with a Francis 4 or 4 1/2 footer because as I mentioned above, they have a unique design that sets them apart from other fiberglass antennas that compensates for other flaws in the system. You can find a 4 footer in most truck stops and 4 1/2 footers online. Replace the factory antenna and if that works you have a cheap fix that will serve your needs. The better choice would be to replace the antenna, coax, and mount with your own because even the cheapest truckstop coax is better than the factory junk. Whatever you do, do it soon. A flawed antenna system will overheat a radio (when you key the mic) and that’s an expensive fix if the final transistors burn out. I’ve seen a few drivers who just plugged their radios in and never gave it a second thought because they could communicate for a mile or so. Then they blame the “POS radio” when they could’ve taken steps to avoid it from happening.