My brother helped me install the belly-mounted comm antennas while he was in town this weekend. In the photo below we're lining up the antennas and drilling the mounting holes… much easier to do it with the antennas inside the fuselage than outside:
My camera was low on batteries so I didn't get a picture, but we made doublers for the antennas out of 0.050" alclad. You can kind of see one in this photo:
Since the antennas are grounded via their mounting screws, ensuring good electrical contact is essential for proper antenna performance. I used an alodine pen to corrosion-proof all the mating surfaces:
Here's a better shot of the fuselage doublers, with the alodine drying. It looks blotchy but that doesn't really matter.
I likewise cleaned, scuffed, and alodined the areas of the fuselage floor destined to be covered by the doublers:
Adam helped me rivet the doublers to the floor:
They're also attached to the seat ribs with blind rivets – plenty strong. Each antenna is attached with four screws that go into floating nutplates, and the BNC connector protrudes through the hole in the middle.
Voila, antennas. This arrangement should make for easy wiring, keep the antennas out of the plume of exhaust gunk, and satisfy the radios' requirement for minimum antenna separation distance.
