what kind of head set are you using? I read that the usual ones with wire to the ear piece actually pick up and channel more electromagnetic radiation into the ear and head. there are ones available that have an air tube that channels sound to the ear, and since there is no wire it eliminates 98% of the radiation. I got one for my daughter and the sound is very good quality.
I still wonder how could it be confirmed that the Cell Phone diodes work, or which ones work. I purchased 3 of a certain kind for my family's Cell Phone s, and noticed other types available as well. I'm getting a combo meter for measuring electromagnetic radiation from Cell Phone and household sources. However, if I understand this correctly, the diodes don't stop the radiation they change it to non harmful wavelengths, so the meter would still pick it up.