Which frequency is commonly used as a secondary beacon with 406 MHz EPIRBs?

• A. 121.5 MHz
• B. 243 MHz
• C. 156.8 MHz
• D. 406 MHz

Answer: (C)

When an EPIRB is activated, it first sends a digital distress alert on 406 MHz to the satellite system, which provides the vessel’s identity and location. A secondary beacon frequency is used to help rescuers pinpoint the beacon once they’re nearby. The frequency most commonly used for this homing purpose with civilian 406 MHz EPIRBs is 121.5 MHz. This frequency is specifically designated for beacon homing by SAR teams, aircraft, and ships in the vicinity of the distress.

The other options don’t fit as the standard secondary homing frequency: 243 MHz is a military distress channel, not the civilian beacons’ routine homing frequency; 156.8 MHz is the marine voice distress channel (Channel 16) used for voice calls, not for beacon homing; and 406 MHz is the primary distress frequency for digital alerts, not the secondary homing beacon.