How beacons work

Emergency beacons emit a signal that allows New Zealand Search and Rescue to find you. They come in three different types:

• ELT is an 'emergency locator transmitter' mounted on planes
  
  
• EPIRB is an 'emergency position indicating radio beacon' used on boats
  
  
• PLB (pictured) is a 'personal locator beacon' used by individuals for hiking, hunting, kayaking and other outdoor pursuits, and is probably of most interest to consumers. Sometimes they're incorrectly called "Personal EPIRBS". They tend to be smaller and lighter than EPIRBs, usually about the size of a small paperback novel.

Activation depends on the beacon type. In most cases PLBs are activated by the simple press of a button or two buttons simultaneously. EPIRBs can usually be set off by a button as well, but some are automatically set off if they're submerged in water, for example.

All emergency beacons emit a UHF or VHF radio signal when activated. This signal is picked up by satellites or aircraft and the beacon's position is passed on to the Rescue Coordination Centre of New Zealand (RCCNZ) who initiate a search. During 2007 New Zealand Search and Rescue (NZSAR) assisted over 2600 people in more than 2200 separate search and rescue incidents.

GPS

Beacons with built-in GPS narrow down the search area from as much as 5 nautical miles down to 300 metres. As Duncan Ferner from the New Zealand Search and Rescue Council says, "GPS essentially takes the 'search' issue out of search and rescue."

Rodney Bracefield from RCCNZ says GPS also means a faster response. "This enables us to receive an approximate position at the same time as we receive notification of the Hex Id (the unique code for your beacon). Without the GPS we have to wait for a second satellite pass which may take as long as 4.5 hours."

Using a beacon

There are a few things you need to be aware of when using a beacon:

• The most important thing is to only use your beacon in a life-threatening situation. Non-urgent use wastes the resources of our search and rescue people, and puts their lives in danger too. Believe it or not, some countries have banned PLBs because they get so many false alarms.
  
  
• Register your beacon and keep your contact details up-to-date.
  
  
• Beacons are one-way only, so you won't get any confirmation that your signal has been received until a helicopter or search party finds you.
  
  
• An activated beacon will transmit for around 24 to 48 hours and then stop. This is where rescuers will fix your position so it's important to remain there - don't try to walk your way out or paddle to the next island after you've activated the beacon - just stay put.
  
  
• Try to have a clear view of the sky. Beacons need line-of-sight to a satellite and are less effective in dense bush, valleys and gorges.