So after about three weeks of fiddling around i finally got my FT-7900R mounted in the car and mostly happy with how it sits. Running it off a proper fused line direct to the battery which made a huge difference over the cigarette lighter thing i was doing before, way less noise on receive.

Anyway my main question is about the antenna. Right now i have a mag mount NMO dual band whip stuck on the roof toward the back and it works fine but ive been reading about doing a proper hole mount through the roof or maybe the trunk lip and im not sure if its worth the effort. Like is the performance difference actually noticeable day to day or is it more of a theoretical thing? I mostly use it for hitting the local repeaters and occasionally some simplex when im out hiking with buddies who have HTs.

Also not sure if it matters but its a 2016 honda civic so not the biggest roof in the world. Anyone done a proper mount on a smaller car?

the difference between a good mag mount and a proper NMO hole mount is real but honestly for repeater work youre probably not going to notice it much unless the repeater is marginal. where it shows up more is on the noise floor, mag mounts can pick up more body noise from the car depending on the car. the coax routing matters a lot too, if youre running the cable through a door or window you're adding a potential noise source and also slowly damaging the coax over time.

on a civic the roof is fine, plenty of people do center of roof mounts. trunk lip mounts are easier if you dont want to drill but you lose a bit because the ground plane isnt as clean. if you ever decide to do it properly id just go center of roof and use a good quality NMO mount with the right length pigtail. just take your time routing the coax and youll be happy with it. the install looks way cleaner too which is kind of satisfying after doing all that other work.

i did almost exactly the same thing on my civic hatch last year, went with a lip mount on the trunk because i was too nervous to drill the roof lol. works fine for what i do which is also mostly repeaters. the ground plane thing is a bit of a compromise but i honestly cant tell the difference in practice. congrats on the direct battery wire that was the first thing my elmer told me to do and it really does clean things up