Before closing up the rear seat floors, I needed to route the RG-400 coax cables from the side walls to the antenna mounting locations under the rear seats.
My antennas attach with nutplates so I can install them later without any need for an access panel.
I drilled a hole in the side of the seat rib to route the cable and I installed a snap bushing. I had previously drilled a hole in the seat floor for routing up into the sidewall.
I decided to crimp the antenna BNC connectors now instead of doing that later under the airplane.
I then test-fit the antennas to make sure they would install easily later.