A few more details added tonight. I know that the tail boom on this helicopter was equiped with a lot more than a communications antenna and I took a stab at what is in the rear coffin shaped housing. Sensors. I am going by pictures of TD's that are in a museum (deactivated) and in a graveyard. None of them are so equipped anymore but I did find a video on YouTube that gave me a clue that the housing was not just a junction box for wiring. It is only a short section of video and not very high res but I was able to spot the black looking circles on the rear of the housing. I had seen other sensor shots showing nothing more than a flat disk so that is what it became. Lot's more screws got used tonight and I have a couple more panels to make. I found it is easier to make the panel then paint it off the heli and assemble using the actual screws to hold it on. No mess and who knows, one day they may come in useful. Take care.