In preparation for closing the rear seat and baggage floors, I fabricated an antenna doubler for the Commant CI-122 whip antenna that I am planning on installing under the rear seats.
I am going to do a little more research on the location before I match drill the holes with the fuselage bottom skins. At the moment, I am planning on putting it in the first bay, just right of the center tunnel.
If I locate the transponder to the rear seat, I will probably move the comm antenna to the first bay just left of the outside bay.