For a long time I have been convinced that there wouldn't be a real problem with people using their mobile phones in airplanes. Figuring that wiring ought to properly insulated and frequencies not necessarily interfering between plane and ground communications, I'd have figured we were safe. A discovery that I made yesterday made me not so sure.
Yesterday, as I was at work, I was listening to my iPod when, suddenly, the volume leaped for no apparrent reason. I thought that it might be the audio file itself, so I rewound and did not experiece the same phenomenon. Later, it happened again, and this time I noticed that the screen had become active (I have the backlight set to 5 seconds) showing the increased volume bar. A few moments later it happened again, this time the volume went lower.
After this third occurence, I had made a correlation between cause and effect. My Blackberry was sitting a few inches from the iPod and on the third occurence of this "problem" I noticed that it had happened at the same time that I sent an email through the Exchange web client, causing the Blackberry to sync with the sent message. At that time, my headphones had experienced the tell-tale interference of GPRS data commnuications, the stuttering and popping we are all used to hearing through desk phones.
After this discovery, it makes me wonder how wide spread the effect could be. Could I develop a device that would send a burst in the direction of a nearby iPod and cause it stop playing, change songs, or change the volume? A bigger question to ask is what are the possible effects in a plane were the FTC and FAA to allow airborne phone use? Could my email to a colleague telling him that he sucks cause feedback into the PA system resulting in lost communication between the pilot and the ground?
My assumtion, after some VERY scientific, technical research and testing, is that the effect on the ipod occurs throught the head phones and not the device itself. Since the headphone jack is also the plug for a remote control, I'd guess that the interference that occurs from the phone is at the same frequencies as the iPod remote's control queues. I'd be interested to know if other's have experienced this, or if I've just got rubbish headphones.