Explanation: Satellite communication systems, like Inmarsat, require an unobstructed line of sight to the satellite. Installing antennas as high as practical and free from shadowing by ship structures (masts, funnels, cranes, other antennas) is critical. Any obstruction will block or attenuate the radio signals, leading to poor performance, dropped connections, or complete communication failure. Maximizing the antenna's clear view of the sky ensures reliable operation regardless of the ship's heading or satellite position. Installing antennas next to other Inmarsat antennas (B) can cause mutual coupling and interference, degrading performance. Connecting to a transmission line with the highest characteristic impedance (C) is incorrect; impedance matching (typically 50 ohms) is crucial for maximum power transfer and minimal signal loss. Installing a filter to attenuate frequencies *above* 1 GHz (D) would block Inmarsat's L-band signals (1.5-1.6 GHz), making communication impossible.