Question 36D5

NAVTEX broadcasts ensure accuracy through a specific method of Forward Error Correction (FEC). Each character of the message is transmitted twice, separated by a brief time interval. The receiver then compares these two instances of the character. If both transmissions match, the character is accepted as correct. This redundancy significantly improves reliability, as the likelihood of both transmissions being corrupted in the same way is reduced, thereby correcting many errors without requiring a retransmission. Option A is incorrect because while some data links use parity checks, NAVTEX's primary accuracy mechanism is character doubling. Option B is incorrect; NAVTEX is a broadcast system and doesn't typically retransmit entire messages on demand for individual errors. Option C is too vague and doesn't describe the specific FEC implementation; option D precisely details how the FEC works for NAVTEX.