I know COM antennas ideally need a 23" radius for ground plane, and that the best place for them at the bottom is the fuselage skin, but I'm wondering if anyone has had success with having one on the forward bottom part of the tailcone, and what kind of performance they got from it.
Context: I originally planned to have two antennas at the bottom of the tailcone - transponder and ADS-B, and added the appropriate doublers and holes for them. With the latest avionics, I no longer need two separate antennas (and have no other antenna that needs to be placed at the bottom), so I have an extra hole in the tailcone, so I'm wondering if I can just use that.
You can see the hole location in this
Lesson learned, don't finalize antenna placement until you actually buy the avionics
I can of course just plug the hole and make another one further forward for the antenna...