Director, Forest Service Utah Avalanche Center
Avalanche transceivers are susceptible to interference by electronic devices, metal objects, and magnets if they are too close. Every day there are more electronic devices being carried into the backcountry. Of particular concern may be heated clothing.
The guidance below provides practical guidance on how to avoid problems with interference. It was created through a collaboration by Avalanche Canada, the US National Avalanche Center, Colorado Avalanche Information Center, Utah Avalanche Center, Northwest Avalanche Center and the six avalanche transceiver manufacturers: Arva, BCA, Black Diamond, Mammut, Orthovox and Pieps. Thanks to Avalanche Canda for creating the images below!
There are two scenarios in which interference may occur:
- Interference with a transmitting transceiver (send mode). This must be addressed and dealt with before going into the backcountry. If you are buried and wearing something causing interference, you will not be able to fix the situation.
- Interference with a receiving transceiver (search mode). This one should also be addressed and fixed before going into the backcountry; however, if a searcher can recognize interference is happening during a search, they would have an opportunity to deal with it as long as they can accurately recognize the interference.
Interference with transceivers generally presents as either reduced range or ghost signals.
The GOOD NEWS is that interference has a simple solution - DISTANCE. Add distance between the transceiver and the object creating interference. The guidance below will help you understand how much distance you need.
The 20/50 rule is that you want your beacon 20cm (8") away from other electronics while transmitting and 50cm (20") away from electronics while searching.