With most handsets, users can only listen to FM radio via the headset, which also serves as the antenna. The FM RF signal is picked up by the FM receiver while the audio is sent to the speaker by the audio amplifier. By using the headset as a quarter wave length antenna of 75 cm, there is maximum signal pick up as the antenna is used at the resonance frequency. Also, the antenna output is matched to the FM receiver’s input for maximum power transfer.