Which frequency is not listed among the potential DF monitoring frequencies in the material?

Which frequency is not listed among the potential DF monitoring frequencies in the material?

• A. 121.5 MHz
• B. 156.525 MHz
• C. 243 MHz
• D. 400 MHz

Answer: (D)

Direction finding (DF) monitoring focuses on tuning to the standard distress and emergency beacon channels so you can locate transmissions that indicate a SAR situation. The common frequencies monitored in this context are 121.5 MHz, 156.525 MHz, and 243 MHz, which are internationally recognized for search-and-rescue beacons. These bands are chosen because they are widely used by distress signals and have long-standing procedures for interception and homing. The 400 MHz range, however, isn’t part of that distress-beacon set; it sits outside the established DF monitoring frequencies for SAR use. So 400 MHz is not listed among the potential DF monitoring frequencies.

Direction finding (DF) monitoring focuses on tuning to the standard distress and emergency beacon channels so you can locate transmissions that indicate a SAR situation. The common frequencies monitored in this context are 121.5 MHz, 156.525 MHz, and 243 MHz, which are internationally recognized for search-and-rescue beacons. These bands are chosen because they are widely used by distress signals and have long-standing procedures for interception and homing. The 400 MHz range, however, isn’t part of that distress-beacon set; it sits outside the established DF monitoring frequencies for SAR use. So 400 MHz is not listed among the potential DF monitoring frequencies.