UPDATE::: I'm planning to use SO239/PL259 connectors for all of the external connections, which means that the metal ammo cans will share the radio ground. It's a good thing that I checked the grounding on the solar system. The solar controller is positive ground, so everything between the panel and the battery output will need to be isolated from the radio ground. That means that I will NOT be able to put the solar controller in the box with the duplexer. Instead, I will mount the controller on the panel and run the battery line from the controller directly to the can which contains the battery (12aH SLA), so I will no longer need to put DC voltage on the RX cable. Sure, I could use a TRS (T and R only) or XLR connector, but then I need a dedicated cable type (believe it or not, cabling is the part that I planned to keep simple from the start - it's all using the same connector).