So ive been running a mag mount diamond NR770H on my F-150 for about a year now and honestly its been fine for what i do, mostly hitting the local 2m and 70cm repeaters on the commute. But ive noticed the signal isnt super consistent, sometimes i lose the repeater going through the same stretch of road that never used to be a problem, and i keep wondering if its the mag mount being slightly off or just the antenna itself.

A buddy of mine keeps telling me to just drill and do a proper NMO mount through the roof and be done with it. And i know hes probably right from a pure RF standpoint, better ground plane, no cable pinched in the door, all that. But its a truck and im honestly hesitant to put a hole in the roof. Ive seen the trunk lip mounts and the ones that go on the rain gutter but i dont know how well those actually perform compared to a real through-hole NMO. Anyone actually done a side by side or at least switched from one to the other and noticed a real difference? Or am i overthinking this and the mag mount is probably fine and its something else causing the dropouts?

Honestly the mag mount is probably your culprit, especially if the cable is going through a door or window - every little kink in that coax adds up and the ground plane contact on painted metal is never as solid as people think. I drilled my Tacoma about three years ago and the difference was noticeable, like repeaters i could barely hit before were suddenly full quieting. Not a huge jump but definitely real.

That said if you really dont want to drill, a trunk lip mount done right with a proper bonding strap to the body is a decent middle ground. The issue is a lot of people skip the bonding and then wonder why performance is mediocre. The mount itself isnt the whole story, its whether the antenna has a good RF ground. If you go that route i'd use a short piece of braid or a ground strap to the nearest chassis bolt and actually test it rather than just assuming its ok.

i put an NMO through the roof of my jeep and never looked back, but yeah i get the hesitation on a newer vehicle. what i will say is the dropouts you're describing on the same stretch of road every time makes me think its more likely a repeater coverage edge or maybe multipath off a building or overpass rather than your mount. mag mounts on a big truck roof are actually not that bad groundplane wise assuming decent contact. have you tried a different route and see if it still drops?