Decided to mount the ELT Antenna behind the Cabin Frame. I've seen where this spot is used by quite a few builders. Seems reasonable given there are few other choices on this airframe for this -- especially considering I want to keep it inside out of the airstream. The antenna is attached using #6 screws holding tie-wrap anchors to rivnuts in the Cabin Frame. Once the Cabin Frame is painted, I will likely use black tie-wraps to secure the antenna - a minor detail. Routing of the coaxial and cable for the remote test button on the panel are next.