We have found that large antennas will
damage the very thin roof top with the 3/4
nmo mount.We now use the uni-bit and make a 3/8 hole
to the side and make it 5/8 long then mount the antenna
( The hole is made with the uni-bit 1/2 model)
kit in the hole and turn it 90 degrees so the plate is across
the 3/8 side.No more bad returns from car washes.