Long time reader, first time poster.
Figured I would post what I did to work with the stock coax/antenna mount on a 2018 Peterbilt 579 EPIQ mid roof as a company driver without the ability to heavily modify the truck.
I am on a budget and this is not a "super trucker" setup. This is just to get a decently ranged CB working for day to day flatbedding needs and routine freeway communication.
Uniden Bearcat 980 SSB: 189.99$ at Pilot Flying J
Firestick 2 fs4 (4ft) antenna: 29.99$ at Pilot Flying J
Wilson Heavy Duty SS Spring: 15.99$ at Pilot Flying J
CB Antenna Standard Stud: 9.69$ at Pilot Flying J
I used this video to install the CB:
One thing I did tale the time to do thats not in the video is make sure there was no major bends or kinks in the coax, after straightening and wide looping the excess I fed it back into the firewall as straight as possible.
I am attaching photos to this thread, its really nothing special the swr was sitting at 8.43 and antenna test was a fail after CB was installed on the fiberglass antenna and stock connectors. Again, this is really just for the guy looking to get working, I spent some time googling and found that most guides were all about swapping coax, moving the antenna mount etc... For a company driver that just needs the CB to work on decent price point this is for you.
Straighten, wide loop, feed back into firewall excess coax from behind the CB. I also used the stock velcro and the world has not ended.
Remove fiberglass antenna.
Remove connector from coax and clean with QR cleaner.
Install new connector (yes on the stock behind the sleeper mount), screw on spring to base of Firestick then to connector. I did NOT adjust the Firestick at all I just capped it and ran another antenna test and swr calibration on 980 SSB, antenna passed and swr dropped 8.43 to 1.2. I am easily getting heard out to between 2 and 3 miles and listening much farther out, especially on USB and LSB. The antenna will sit just a bit above 13'6" hence the spring, it should be noted that I am a flatbedder so I canmot speak to the 4 ft length working as good for a dry van, you may need to consider the 5 ft Firestick.
This meets my needs at shippers/recievers and basic OTR commication. I hope this helps someone out there. In the end I spent about 250$.
See attached photos, sorry I dont have a picture host account o insert at the appropiate points in the post.