so ive been running a mag mount on my F-150 for like two years now and finally got around to drilling for a proper NMO mount last weekend. figured id share since i spent way too long reading threads before doing it and most of them were kind of old or vague about the actual install details.

did the hole just forward of the rear edge of the roof, roughly centered. used a step bit and went slow, had a friend hold a shop vac underneath the headliner which actually worked surprisingly well for catching most of the metal shavings. ran the coax down the A pillar and tucked it behind the door seal, pretty clean route. the NMO itself is a Larsen mount and i threw a 5/8 wave 2m whip on it to start.

honestly the difference on receive is noticeable compared to the mag mount i was using. im running into the same mobile rig so its not that. the mag mount was always kind of sketchy on the ground plane since it was sitting on the bed cover which is fiberglass. that was probably most of my problem. anyway now im wondering if its worth putting up something for 70cm too or just getting a dual band whip. the single band 2m one is a Larsen 2/70 actually wait no that came with the package, its the NMO2/70B i think, so its already dual band. nevermind. its working fine.

the fiberglass bed cover killing your ground plane explains a lot. mag mounts need a solid conductive surface under them and people underestimate how much that matters, especially on receive. glad the NMO sorted it out. i did basically the same install on a Tacoma a few years back and ran the coax through the door pillar the same way, holds up fine even after a lot of weather.

one thing worth checking on those Larsen dual band whips — the 2/70 has a decent pattern on 2m but 70cm performance can be a bit meh depending on the whip length and tuning. if you ever grab an antenna analyzer and put it on there just out of curiosity id be interested what the SWR looks like on the UHF side. sometimes theyre fine, sometimes they need a bit of trimming. probably not worth worrying about unless youre noticing any range issues on 70cm.

yeah mag mount on fiberglass is basically just asking for grief, ive seen guys running them on plastic toolbox lids on truck beds wondering why nothing works lol. good call on drilling it, always better long term anyway since the mag mount will eventually scratch the paint no matter how careful you are.