so i've been running a lip mount with a diamond NR770H on my truck for about two years and honestly it works fine but i keep reading that NMO is the way to go and i'm starting to second guess myself. the lip mount is on the passenger side rear, grounded okay i think, SWR is like 1.3 on 2m and a bit higher on 70cm but still under 1.8 so i figured whatever it's good enough.

but then i was at a club meeting last month and this guy says my ground plane is probably garbage and i'm leaving a few dB on the table. now i cant stop thinking about it. drilling a hole in the roof of a truck i'm still making payments on feels like a commitment though. is it actually worth it or is this one of those things that sounds better on paper and makes almost no real difference on the air

honestly the difference between a good lip mount and a proper NMO through the roof is real but whether it matters depends on what you're doing. for everyday repeater work in decent range, probably not gonna change your life. but if you're doing simplex or running low power a lot, a solid ground plane actually does make a noticeable difference. the roof center mount gives you a nice symmetrical ground plane all the way around instead of whatever the lip is contacting.

that said i ran a trunk lip mount for years and worked everything i needed to. the SWR numbers you're describing are fine, not ideal but fine. if you ever sell the truck or trade it in you'll appreciate not having a hole in the roof. i eventually drilled mine and yeah it's better but i wouldnt lose sleep over it if you dont want to commit to the hole.

the ground plane thing is real, ive tested it with a buddys nanoVNA and the impedance on a lip mount was all over the place compared to a proper bonded NMO install. not saying yours is bad just that it varies a lot by vehicle. some guys use the hood or hatch and get decent results, others its a mess.

one option if you dont want to drill is a mag mount on the roof, like a quality one not the cheap ones, gives you a pretty good ground plane without the hole. not as clean as NMO but better than a lip mount usually. or look at the fender NMO mounts that thread into an existing hole, some trucks have those antenna boss holes already punched in the fender from the factory