The majority of VLF transmitters are primarily used for what purpose?

The majority of Very Low Frequency (VLF) transmitters are primarily used for fleet communications or navigation due to their unique propagation characteristics. VLF waves, which have frequencies typically between 3 kHz and 30 kHz, can penetrate water and soil, allowing for reliable communication with submarines and other naval vessels even when submerged. This capability makes them essential for naval operations and maritime navigation.

Additionally, VLF transmitters are also used in some other specialized applications, such as time signals for certain navigation systems and communication with isolated or remote assets at sea. The long wavelength of VLF signals allows them to follow the curvature of the Earth, which contributes to their effectiveness in long-range communication without the need for line-of-sight.

Other options, while they may utilize different frequency ranges or methods, do not align with the primary and most effective use of VLF frequencies in communication.