I'm debating between mounting my 2m/70cm antenna on the center of my truck roof versus using one of those NMO fender mounts. I've seen comparisons showing a mag mount 5/8 on the trunk lid versus the same mag mount on the center of the roof - big difference favoring the roof location.

But I'm concerned about clearance issues with my garage and low branches. The fender mount seems more practical but I'm wondering about the performance trade-off. Anyone have real-world experience comparing these mounting locations?

The center of a vehicle roof is considered the best for mobile antenna placement. Drilling a hole for a permanent installation in the center of the roof is considered the cleanest and best method, provided the roof is metal. However, if clearance is an issue, fender mounts work reasonably well - just expect some directional pattern distortion.

I plan on mounting mine at the center of the front engine hood right at the base of the front windscreen. The ground plane provided by the front hood should be significant. Have you considered a hood-edge mount? It's a good compromise between roof performance and clearance issues.

I run a fender mount on my daily driver and roof mount on my expedition truck. Ground plane size requirements differ by frequency, impacting effectiveness. The car roof center provides the best ground plane and minimal obstruction, ensuring peak performance. For casual repeater work, fender mount is fine - you'll notice the difference more on simplex or weak signal work.