Steve Achelis, a part-time patroller at Brighton Ski Resort, Utah, and former Commander of the Salt Lake County Sheriff's Search and Rescue Team, says online that cell phones and electrical devices can interfere with avalanche transceivers. Your gadgets mostly affect the searching beacon more than the transmitting beacon but if you're planning a trek into the backcountry, keep them off to be safe.
All computing devices leak RF energy, but the higher the clock speeds of our computing devices, the more energy they radiate. One report from a member of TGR's ski and board forum said that "After multiple tests, I consistently got the E04 error message about three seconds after placing my cell phone (t-mobile GSM) on top of the transceiver in the "send" mode. I also found something that could be equally disturbing in the field. In the search mode, if I brought the Pieps within six inches or so of the cell phone, it would register multiple burials. For both tests the cell phone was turned on, but I was not making or receiving calls."
Numerous reports on the web confirm that playing an iPod and/or leaving your iPhone on (yet not in use) will cause more RFI (radio frequency interference) than a CDMA phone might in all avalanche beacons at close range .
Technicians surmise that an iPhone, with its 620 MHz processor, leaks a more stray RF energy than a typical cell phone, which is likely to be clocked at a tenth as fast. The bottom line to take from this information is to turn off your devices when wearing your beacon. The potential for an iPod to be inadvertently left on and then cause interference in a beacon search is very real. In addition, if you have to turn on your phone to call for help, make sure you are some distance from other searching beacons.
If for some reason you can't turn off a device, at least keep it as far away from your transceiver as possible. While we're on the subject, metal objects (pocket knifes, bottle openers, roach clips) should also be kept away from your transmitting beacon. For diehard tunes fans, TGR forum poster ‘Pechelman' mentioned the idea of designing a "Dead Zone" pocket in your jacket or pants to block RF signals. Line the pocket with a fine metal mesh. Whatever is in the pocket would not be able to get an outside signal, (you couldn't receive calls or texts), but iPods and other MP3s would run just fine.