A signal amplifier system is provided for a mobile or portable broadcast receiver. The signal amplifier system includes an operational circuitry, a signal generator and a voltage supply. The signal generator receives a field strength signal that indicates a field strength of at least one broadcast signal. The signal generator outputs a supply voltage control signal based on the field strength signal. The voltage supply provides one of a first supply voltage and a second supply voltage to the operational circuitry in accordance with the supply voltage control signal.