WASHINGTON: The U.S. radio industry has earned some derision lately for its effort to have legislators make FM reception capabilities mandatory in mobile telephones. One argument that has yet to made in that debate is over electromagnetic fields. A YouTube video from Switzerland raises the question.
Unlike listening to FM or DAB/DAB+ radio, streaming via Wi-Fi or 3G uses a return channel, meaning that the receiver also acts as a transmitter. In the video, measurements are taken using a Gigahertz Solutions HF 35C RF analyzer while tuning station Couleur 3 through different modes.
Background radiation in the room where the tests was recorded is 1–4 μW/m2. Using an HTC Desire Android-based mobile phone, streaming via 3G/HSPA and Wi-Fi are both tried, and the field strength detected by the meter increases dramatically. Listening to the same station via the phone’s FM receiver, there is little increase in EM field strength. To test DAB, the meter is pointed toward a Revo UNO 2 DAB/DAB+ receiver tuning Couleur 3’s VHF band III DAB+ signal.
No judgment is made based on the video as to the safety of the electromagnetic fields generated while streaming audio. However, it is clear that a passive FM or DAB/DAB+ receiver does not generate the sort of electromagnetic field that streaming to a wireless device does. -- from Radio World
