Emergency Position-Indicating Radio Beacons or EPIRB as it is called are tracking transmitters that help in detecting and locating vessels, ships and aircrafts in distress. As the title suggests, this article will present information about the 406 class EPIRB.

WHAT ARE 406 CLASS EPIRB?

The 406 MHz EPIRB is a radio beacon that has been designed to operate with satellites. The signal frequency i.e. 406 MHz has been designated worldwide for use in the sole purpose of distress. The signal from the beacon permits a satellite local user terminal to pinpoint the location of the EPIRB and identify the vessel anywhere in the entire world.
These units are detectable by CORPAS-SARSAT satellites and the many geostationary GOES weather satellites. When GEOSTAR system detects EPIRBs, it sends an instant alert to the rescue personnel but without information concerning the location, unless the EPIRB is equipped with a GPS receiver.

However, EPIRBs detected by CORPAS-SARSAT satellites offer rescue authorities the location of distress. But, alerting may be delayed by 60 minutes or more. These EPIRBs also come fully equipped with 121.5 MHz homing signal that allows aircraft and rescue craft to find the vessel quickly.

The 406 Class EPIRB needs to be certified by the U.S. Coast Guard approved laboratories before they can be sold in the country.
CLASSIFICATIONS OF 406 MHz EPIRB

EPIRBs are classified into two categories- recognized and unrecognized category. Recognized category is further divided into two sub-classifications, which are

Category I: 406 MHz. float free, automatically activated beacon.
Category II: 406 MHz. similar to category one, except is activated manually.

Category I can be activated both manually and automatically. When the EPIRB is released from its bracket, the beacon is automatically activated. Category I EPIRBs come in a special bracket that is equipped with a hydrostatic release. This mechanism frees the EPIRB at a water depth of 3-10 feet. This floating EPIRB begins transmitting once it reaches the surface. These EPIRBs should always be placed outside the vessels cabin where it can float free in the case of an accident or mishap.

Category II are units that can only be activated manually. These should be kept and stored in an accessible location on board for quick access in case of an emergency.

406 MHz EPIRBs come with a self-test function that can help you test the unit. They can also be tested inside a specially designed container that does not allow its reception by any satellite. Remember, testing a 406 MHz EPIRB by permitting it to radiate outside such containers is against the law.

406 MHz EPIRBs use a lithium battery that is specially designed for low-power consumption and long-term operation. Batteries of this unit must be replaced in accordance to the date stated on the label using the model specified by the producer. And, it is wise to get the battery of the unit replaced by an approved dealer.

SOME 406 BEACON FACTS:
•    When turned on, they transmit for a quarter of a second, and transmit a digital burst every 50 second after that.
•    These beacons must be registered.
•    They are the only beacons that are compatible with the MEOSAR(DASS) system