Electromagnetic interference has long been a known issue with avalanche transceivers. But how much of an issue? And what do we do about it?
The UIAA released guidelines earlier this month describing what types of electromagnetic interference affect avalanche transceivers in both transmit and receive modes. Included in their findings are guidelines for how to keep your avalanche transceiver functioning properly by separating it from various types of electromagnetic radiation and objects that cause EMI (Electromagnetic Interference).
What is the UIAA?
The UIAA is The Union Internationale des Associations D'Alpinism, or International Climbing and Mountaineering Federation. It was founded in 1932 and, as of its 2022 General Assembly, has a global presence on six continents representing 97 member associations and federations in 72 countries.
The UIAA began creating safety standards in 1960 with the testing of ropes. It has since developed standards for over 25 types of safety equipment, including helmets, harnesses and crampons. The UIAA collaborates with CEN, the European Committee for Standardization, for the harmonization of standards. In some cases, the UIAA asks for additional tests making the standard stricter than the CEN. Thus, the UIAA standards may differ slightly from CEN standards.
Based on overwhelming and compelling evidence submitted to the UIAA, they issued the following statement:
ELECTROMAGNETIC INTERFERENCE IN AVALANCHE TRANSCEIVERS
SEND - Transmit Mode
all devices may remain in use > 20cm from sources of interference:
Keep your phone in a pocket (pants) opposite to the transceiver to avoid the devices coming to rest close to one another in the case of an avalanche, thus shielding the transmission signal. Do not carry a phone in your jacket pocket (nor an action camera at chest level) while wearing an avalanche transceiver in its cradle. Talk about the topic in your group, make yourselves aware of the problem of interference sources once again.
SEARCH – Receive mode
Only absolutely necessary devices may stay on
Searching rescuer: all devices OFF
- Take off heated gloves.
Other persons in proximity: >10m distance all devices may remain in use
When using an affected system, you may need to consider searching without your electric airbag.
Companion rescue in a group:
To save time, or in case you are not familiar with turning your devices off, consider handing electronic devices to someone who is not actively searching.
SOURCES OF INTERFERENCE
Passive Interference affecting SEND and SEARCH:
Active Interference affecting SEARCH:
INTERFERENCE POSSIBLE CONSEQUENCES
Differentiate "signal of a buried subject" from "false positives" [based on analog sound]
SEARCHING IN HEAVILY DISTURBED AREAS