It seems that to sell a GSM mobile phone, companies like Apple, Motorola, Sony Ericsson and many others invest a considerable amount of money in EMI testing them. Yet they still interfere with my stereo, radio, computer speakers, and other devices. Why?
Electronic – If mobile phones have to go through such extensive FCC/CE/EMI testing, why do they interfere with the radio
The interference caused by GSM phones is an intentional radiator that is within the required limits of regulations.
I tend to blame the other devices for not shielding well enough. Any wireless device is going to have harmonics, its just a way of life and it just so happens that one of the harmonics with many GSM devices is in an audible range.