User's Manual

3 PURPOSE

An Emergency Position Indicating Radio Beacon (EPIRB) is used to alert search and

rescue services in the event of an emergency. It does this by transmitting a coded

message on the 406MHz distress frequency. This message is relayed via satellite and

earth station to the nearest rescue co-ordination centre.

The satellite system is run by COSPAS-SARSAT, and has already been described.

With the geostationary satellite section being commissioned, the alerting delay is

reduced from typically 90 minutes to a few minutes within the geostationary satellite

coverage.

Instant alerting is good news, but they still need to know where you are. The

advantage of the Precision 406 EPIRB is that it has a built in GPS receiver, so within

minutes of activation it will have determined your latitude / longitude coordinates and

will have transmitted these to the rescue centre. The position fix is accurate to 150m*.

To operate properly the Precision 406 needs a clear view of the whole sky. If its view is

blocked and it is unable to get a position fix, then the system defaults to using a polar

orbiting satellite to determine position. In this case, there is typically a 45 minute delay

before the position is known and the accuracy is limited to within 5km (3 miles). This is

the original system that standard (non-GPS) EPIRBs use. To get the full advantage of

the Precision 406 it is important to give it a clear view of the whole sky.

The Precision 406 transmits a message that identifies the exact vessel to which it was

registered. Knowing which vessel is in distress allows the rescue services to eliminate

false alarms and launch an appropriate rescue.

The Precision 406 also has a secondary distress transmitter. This transmits on

121.5MHz and is used for “homing” purposes. When the rescue services get close,

this allows them to direction find on the signal. To cater for searches at night, the

Precision 406 has a bright flashing light that aids final visual location.

READY

TEST

PRESS TO

Antenna

Strobe

Green lamp

Program point

Sea contacts

Lanyard

ON button

under here

READY

button

Battery expiry date

Red lamp

* If the programmed identity

is a Radio Call Sign (RCS)

then accuracy is limited to 5km