so ive been trying to figure out the best way to run coax from the trunk lip mount on my F-150 up to the radio in the cab and i keep second guessing myself. right now ive got maybe 15 feet of LMR-240 going from the antenna, under the weather stripping on the rear door, across the headliner and down the A pillar. it works but honestly the SWR looks a little weird on 70cm and i dunno if its the coax routing or if i kinked something somewhere in the door jamb area. the radio itself is mounted under the dash on a RAM mount which i like a lot, power runs direct to the battery with a fuse inline about 6 inches from the battery, so thats fine i think.

the 2m side seems totally normal, like 1.1:1 across the band which is great. but on 440 im seeing it climb up toward 1.8 or so at the high end of the band. the antenna is a Tram 1185 dual band so it should be resonant on both. anyone dealt with this before or know if maybe the coax pinching in the door jamb could do this? i really dont want to pull it all apart again if i can avoid it

yeah the door jamb pinch is almost certainly your problem on UHF. coax is way more sensitive to that kind of thing at 440 than at 146, the wavelength is short enough that even a small kink or compression point can mess with the impedance. i did the same thing on my Tacoma years ago and had almost the exact same symptom, 2m was fine, 70cm was off. what i ended up doing was routing through the actual rubber grommet on the firewall instead and going under the truck instead of through the cab. took an extra hour but SWR on 440 dropped right down.

the Tram 1185 is a decent antenna, shouldn't be the issue. if you really dont want to re-route, you could try to very carefully open that door jamb section back up and see if the coax looks pinched or has any weird bends. sometimes you can get away with repositioning it just slightly and the problem goes away.

i had a similar setup in my explorer and honestly i just ended up drilling a small hole through the firewall and using a grommet. felt a little scary to do but it came out really clean and no more coax weirdness. just make sure you know whats on the other side before you drill lol