so i finally got around to putting a proper dual band antenna on the truck, been running a mag mount for like two years and decided to do a real NMO mount through the roof. went with a Diamond NR770HNMO which ive heard good things about. the radio is a Yaesu FT-7900R and everything looked fine when i wired it up but when i checked SWR on 2m it was sitting around 1.8:1 on most of the band and kind of spikes near the edges. on 70cm it seemed okay, maybe 1.4:1 or so.

i dont think ive done anything obviously wrong, the coax is RG-8X and the connector on the radio end is a PL-259 i soldered myself which honestly im not super confident about. the NMO adapter and mount itself should be fine, its a Larsen mount and i made sure the hole was clean and grounded to the body. just not sure if 1.8 on 2m is something to worry about or if im being paranoid about this. the radio seems to hit repeaters fine so maybe its okay?

1.8:1 on 2m isn't the end of the world but it's definitely worth tracking down before you leave it. honestly the first place i'd look is that PL-259 you soldered yourself — i've chased weird SWR issues for weeks on mobile installs only to find out it was a cold solder joint or a tiny bit of braid touching the center pin. if you have a second connector or even just some spare coax you can do a quick swap and see if the reading changes.

also worth double checking that the NMO stud is actually making good contact with the body ground. sometimes the paint under the mount washer causes issues even if you think you scraped it clean. the Diamond 770 is a good antenna and should tune up pretty flat across 2m when everything's happy. what are you using to measure SWR, a dedicated meter or through the radio?

yeah im running a pretty similar setup in my Tacoma with the same antenna actually and mine reads like 1.3 across most of 2m so something is a bit off on yours. that said i drove around for months with a 1.7 reading before i figured out my coax had a little nick in it from a sharp edge under the headliner. the radio still worked fine the whole time but i felt better fixing it.

hitting repeaters fine is a good sign at least, you're not dumping a ton of power into a dummy load or anything. might just start by remaking that connector like the other guy said, that's the cheapest and easiest thing to rule out first