I finally got back to building my CX4. I cut a hole in the forward sloping floor in front of the center spar so I can mount my Comm antenna. While I was at it, I created a heel step out of scrap aluminum angle so that it shares the bottom 3 screws to the cover. This heel step will enable me to catch it with my heel to allow me to use my legs to help me exit the cockpit.
Guys, this is a great location for the Comm antenna, if not the only location on the belly of the airplane, so cut this access hole BEFORE you install the forward floor panel. It would make it so much easier.