Question 1-19D3

GMDSS VHF communications, primarily used for short-range line-of-sight ship-to-ship and ship-to-shore voice and DSC (Digital Selective Calling), rely on predictable signal propagation. For maximum signal transfer and compatibility with other vessels and shore stations, antennas must have matching polarization. The standard for maritime VHF communications is **vertical polarization**. This ensures efficient communication across the network of stations, which are also vertically polarized. A) A horizontally polarized circular antenna would result in significant signal loss when communicating with the predominantly vertically polarized antennas used by other vessels and shore stations. Circular polarization is also not typical for this application. B) Long wire antennas are designed for lower frequencies, specifically HF (high frequency) bands, not VHF (very high frequency). They are physically too large and operate on the wrong frequency range for GMDSS VHF. The most common GMDSS VHF antenna is a vertically polarized omnidirectional antenna, often a vertical whip or collinear array. Since none of the provided options describe such an antenna, "None of the above" is the correct answer.