NZ's RSM called in to help locate PLB

New Zealand’s Rescue Coordination Centre (RCC) recently called on Radio Spectrum Management (RSM) to provide help in locating an unregistered personal locator beacon (PLB).

Authorities suspected the beacon was in a location that obscured from detection from above, since satellites passing overhead were unable to detect it.

In addition, aircraft monitoring the PLB’s frequency (121.5 MHz) were unable to hear the signal despite it apparently being located quite close to an airport.

The RCC provided RSM a PLB location fix with a tolerance of ±6 nautical miles (10.8 kilometres).

Upon investigation, RSM was able to detect transmissions (a 500 millisecond burst every 50 seconds) on 406 MHz, around two kilometres from where the PLB was finally located.

RSM used its Automatic Direction Finder to provide bearings on these transmissions and, approximately 100 metres from the PLB, the homing signal was received.

Although tracking was made easier by the almost-constant nature of the homing signal, RSM personnel had to resort to manual tracking to find its exact location.

Finally, due to health and safety concerns regarding the locality, New Zealand Police was asked to assist with retrieval of the device.

RSM has reminded users that PLBs are to be used for distress situations only and that registration of 406 MHz PLBs is a legal requirement. Registration makes it easier for the RCC to contact the owner when a PLB is activated.

Image credit: ©stock.adobe.com/au/kstudija

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