Early in 2001 we published the first article in English about how mobile phones could affect avalanche transceivers, particuarly digital ones. But who would have thought that a simple head torch could pose problems.
Our friends at Bivouak.net found the following notice on the Petzl Tikka Plus head torch :
“The accuracy of your avalanche beacon may be affected when used close to the Petzl Tikka Plus, Zipka Plus and Tackikka Plus. In case of interference turn off your light”.
It is maybe difficult to envisage circumstances where you would need your head torch switched on. Although an avalanche at Tignes that occurred at nightfall and required the rescue services to rig floodlights might be just such an example. Luc tested his lamp and said “it wasn’t interference I heard in my good old Ortovox F1 but something more akin to a 747 coming in to land.” Petzl told Bivouak.net that digital beacons can be affected as well. The problem lies with the electronics which enable different light intensities on the diodes of the Tikka plus. The electronics are fairly simple and this is the cause of the interference.
At PisteHors.com we’ve also noticed interference between a Suunto altimeter watch and an Arva 9000. Although in most cases this interference shouldn’t affect a search the message is clear – keep the avalanche zone clear of noise – both human and electronic.