I've bought a few 50MHz-6GHz directional coupler([SEDC-10-63+][1]), each for 75$. Here is a picture of this expensive coupler!

[![directional coupler][2]][2]


Unfortunately one of these couplers was not working from the beginning so I decided to put the cover up and get a glimpse of inside. The problem is I cannot understand what is this big black component(Probably a ferrite) do And how it contribute to the coupling or directivity

##Coupler Inside
[![enter image description here][3]][3]
[![enter image description here][4]][4]

I also wondering if the cover do anything more than simple a cover. The top cover feels like a plastic but sounds like a ceramic object.

##Cover

[![enter image description here][5]][5]
[![enter image description here][6]][6]

##Update 1
What does this 1150 component do? connect output to the coupled port? doesn't this decrese the directivity?
[![enter image description here][7]][7]

Thanks


  [1]: https://www.minicircuits.com/pdfs/SEDC-10-63+.pdf
  [2]: https://i.sstatic.net/PMT5n.png
  [3]: https://i.sstatic.net/FniqO.jpg
  [4]: https://i.sstatic.net/0taE0.jpg
  [5]: https://i.sstatic.net/HNwC6.jpg
  [6]: https://i.sstatic.net/1ZFJ6.jpg
  [7]: https://i.sstatic.net/miNnF.jpg