We are developing a shipboard system which needs to be connected in a IT network (Unearthed neutral). In order to comply with this scheme we need to avoid negative-grounded, as all the metal enclosures and cable shielding needs to be grounded to create a protective earth and prevent electric shocks. (With the only exception of some capacitors of EMI filters). We are using isolated power supplies and differential signals for most communications, however some signals or the antenna connection are only possible using coaxial cable.
I have serious doubts about the coaxial connexions as those usually use the shield as negative/reference for the signal. How can two systems or an antenna in a ship be connected using coaxial cable and not introducing direct or indirect connections between supply lines and earth?