Antennas on Carbon Fibre Mast

Hi All,

I am currently trying to figure out why my MBX CAT18 is being outperformed by a Transit duo CAT12

The MBX has 2 Poynting MIMO 402 per cellular module, while the Transit has 1 per module.

The MBX antennas are 4m higher than the Transit ones, connected with an HDF-195 Poynting cable.

The only difference I find is that the Transit antennas are fixed on a steel part of the boat, while the MBX antennas are on the carbon fibre part.

Would this affect by any means the efficiency of the antennas because of the ground plane?

I am all ears to suggestions,

Thank you all!