Fabricated a drill template and used it to mark and drill the antenna connector hole for the COM antenna. Taped a 48 inch ruler to line up with the center rib. Sighted along the antenna to rotate the antenna so it was parallel with the centerline of the airframe. Marked the final two holes using the properly rotated antenna as the template. Drilled the final two holes slightly undersized and filed as needed to enlarge the holes and exactly match the holes in the antenna base. The COM antenna uses two of the holes made for the transponder antenna and covers the large hole that was made for the transponder antenna connector. Made a paper template to follow when adding a COM doubler extension to the previous transponder doubler.

Made a final decision on the transponder antenna location.

Completed marking and drilling the two mounting holes for the cabin heat vent.