May 8, 2020 – I located and installed the doublers for my antennas.
I bought my antennas from Stein. I got two CI-122 bent whip com antennas, and a 104-12 for the transponder and 104-17 for ADSB. Some people questioned whether I needed an antenna for the ADSB, but I’m going to use Dynon. They require a separate antenna, where Garmin does not.
I located the com antennas under the seats, each in the next bay outboard of the sticks.
I made the doublers for both of them. I used the provided gasket for the hole pattern.
Then I added the attach rivet holes and drilled for the nutplates.
Here’s the doublers in place on the outside of the belly so I could drill the holes.
I dimpled the skin for the attach rivets.
I opted not to use the gaskets; I’ll be using the aircraft skin for the ground plane. Therefore I can paint the doublers.
A friend came out and helped me install them.
I moved on to the two monopole antennas. The ground plane for these will be the skin, but grounded from the inside. So I made small (2.5″) doublers and located them both in the belly aft of the baggage bulkhead. The two antennas are diagonally opposite from each other and more than 2 feet apart, which is the requirement for the ADSB antenna. After I made the doublers, I masked off there locations in the belly, then sanded the paint away, and alodined the skin and the doublers. My friend came back out, and we dimpled the skin and then riveted the doublers in place.
So I’m ready to install the antennas, but I’m not going to so they don’t get damaged.