Hi Thomas, If I recall correctly, there are mating PL259 connectors at the base of the mast for all 4 antennas. You should be able to re-configure these to do the checks of the antennas and their feed cables.
The connectors to the AIS unit and VHF Radio are both PL 259 at the chart table, and within easy swapping distance so it’s easy to switch those to test the full cable runs.
