Based on your replies, it does appear that what I had assumed to be a “grounding plate” (please see the attached picture) is in fact an SSB plate…
Further to this, it looks like that my boat was fully prepped for an SSB radio: as I currently replacing all old cables in my masts, I have found an SSB antenna cable running all the way through to the nav desk, while an actual SSB radio has never been installed by the previous owner.
Hence, as you have mentioned above, my “grounding plate” should be connected only to the SSB system. Correct?
