How to take apart the black antenna box?

[dlux200sx]

Well I have the worst of the worst rattles in my car which has been rattling ever since the car is new. It is so loud it sounds like someone taped a baby's rattling toy onto my car.

I can't bring it to honda. Problem is, every single time I bring it, it doesn't rattle. It only rattles between 9pm-7am, or during the day when I don't have time to go to the dealership.

I've had people sit in the back to try to diagnose it, but nobody really knows exactly where it's coming from. They feel and press everywhere but nothing seems to help. But according to most people's ears, it's coming from the black antenna box. The box itself feels sturdy and secure, but maybe there's something INSIDE that is loose and rattling?

Does anyone know how to safely take the box apart?