Question 6A542

United States marine radio beacon stations operate within the designated frequency band of 285 to 315 kHz. This allocation is specific for non-directional beacons (NDBs) used primarily for marine navigation. These beacons transmit a continuous carrier wave modulated with Morse code identification signals, allowing ships equipped with a radio direction finder to determine their bearing relative to the beacon. The other options are incorrect because they encompass broader ranges, include frequencies not allocated for marine radio beacons, or entirely miss the correct frequency segment: * **A) From 280 to 385 kHz** is too broad and extends significantly beyond the upper limit for marine beacons. * **B) From 162 to 385 kHz** is far too wide, covering many other services in the LF/MF bands, and not exclusively or primarily for marine beacons. * **D) From 300 to 465 kHz** includes only a small portion of the marine beacon band and extends well into the aeronautical NDB frequency range, which is distinct.