Had a NMO mount on my Ranger. I installed the thing initially myself and no, it did not leak. Drove under a tree. The center coil on the Comet dual bander caught in a vine and ripped the NMO right out of the roof.
Fix it myself, no leaks.
Put the truck in the shop for clutch work. Mechanic drives truck through partially open overhead door. (it was raining) NMO ripped off again, this time repairs on their dime.
No more NMO holes in anything I own. Mag mounts will leave the vehicle before doing any serious damage, like under trees or in parking decks. Most people are too short to see the the grubby place the magnet makes on the roof after 100,000 miles and the rest don't care.
In the car wash the antenna and mount go in the backseat.
But the thing put out a booming signal, I guess because of the excellent connection to the ground plane
