Subelement F: Maritime Safety Information (M.S.I.)— Topic :
Question 37F6
Element 7R (GMDSS-RO)What is the transmitting range of most NAVTEX stations?
Explanation
NAVTEX stations transmit on medium frequencies (MF), primarily 518 kHz, which utilize *ground wave* propagation. Ground waves travel along the surface of the Earth and follow its curvature, especially effectively over seawater. This allows NAVTEX signals to be reliably received well beyond the visual horizon.
A typical ground wave range for these frequencies and power levels is 200 to 400 nautical miles, providing essential maritime safety information to vessels in coastal and offshore waters. Options A and D describe ranges far too short or modes of propagation (line-of-sight) that are characteristic of higher frequencies (VHF/UHF), not MF. Option C's upwards of 1000 nautical miles during the daytime is generally too extensive for consistent and reliable ground wave coverage.
Related Questions
37F4 Which of these cannot happen when a paper model NAVTEX receiver runs out of paper?37F5 Which of the following is the primary frequency that is used exclusively for NAVTEX broadcasts internationally?38F1 How is a NAVTEX receiver programmed to reject certain messages?38F2 How can reception of certain NAVTEX broadcasts be prevented?38F3 Which of the following statements is true?